this section traces the passage of air from the trachea to the capillaries in the alveolus. the trachea is the largest tube in the respiratory system which is bolstered by 20 or so cartilage rings and smooth muscle. it has a PSCC epithelium with goblet cells and tracheal glands in the submucosa. the trachea then branches into the brochi, which have smatterings of cartilage and are like smaller versions of the trachea. bronchioles (from organ systems: primary for each lung, secondary for each lobe, tertiary for each bronchopulmonary segment) have no cartilage, and epithelium which begins to transition from PSC to simple columnar. terminal bronchioles are the last section of the airway that does not take place in gas exchange, and they have simple columnar epithelium with no goblet cells. next comes the respiratory bronchioles, where gas exchange begins to take place, which have simple cuboidal epithelium and the beginnings of alveoli protruding out from the walls. these transition into alveolar ducts, which are basically smaller respiratory bronchioles with simple squamous epithelium and many alveolar sacs. finally, the air reaches the alveolar sac, which is the end of the passageway.
between the alveolar sacs is the interalveolar septum, where gas exchange with blood actually takes place. this border is lined with type 1 and 2 pneumocytes, involved in gas exchange and surfactant secretion, respectively. thus, in order to reach the blood, gas has to diffuse through: type 1 pneumocyte cell, type 1 pneumocyte basement membrane, endothelial basement membrane, endothelial cell. also between the interalveolar septum are some fibroblasts, alveolar phagocytes, and a scant CT matrix called the zona diffusa.
questions
1. describe the passage of air from the trachea to the alveoli.
2. describe the physical support of the trachea
3. describe the layers of the trachea.
distinguishing characteristics of:
4. bronchi...
5. bronchiole...
6. terminal bronchiole...
7. respiratory bronchiole...
8. alveolar duct...
9. alveolar sac...
10. what are the two alveolar surfaces formed by epithelia?
11. what is inside the interalveolar septa?
12. describe the barrier between blood and air in the alveoli.
answers
1. trachea, bronchi, bronchioles, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli.
2. ~20 cartilage rings with smooth muscle (trachealis) spanning the posterior openings.
3. PSCC in mucosa with goblet cells, sometimes diffuse lymphatic tissue. submucosa of CT and tracheal glands. hyaline cartilage layer, then adventitia.
4. fragmented hyaline cartilage, PSCC with goblet cells.
5. smooth muscle but no cartilage, PSCC to simple columnar epithelium with goblet cells.
6. simple columnar, cilia but no goblet cells. clara cells secrete lipoprotein surfactant.
7. beginning of gas exchange; alveoli begin to protrude through walls. simple cuboidal epithelium with no cilia.
8. like a smaller respiratory bronchiole with many alveolar sacs.
9. terminal room of alveoli at ends of ducts, simple squamous epithelium.
10. type 1 pneumocytes which allow for gas exchange and type 2 pneumocytes which secrete surfactant.
11. CT matrix called zona diffusa, fibroblasts, alveolar phagocytes, capillaries. zone fiber phago cap
12. pneumocyte, pneumocyte basement membrane, endothelium basement membrane, endothelium.
Showing posts with label histology. Show all posts
Showing posts with label histology. Show all posts
Thursday, December 4, 2008
histology: the integument
the integument is divided into three basic layers: on the surface is the epidermis, then the dermis, then the hypodermis. the epidermis itself has several layers, the deepest of which is called the stratum basale which is on the basement membrane of the epidermis and contains mitotically active keratinocytes, which are epithelial cells containing keratin, which is a sulfur bound protein. also scattered in this layer are other cells such as melaninocytes which produce melanin, Langerhans cells which are antigen presenting cells, and Merkel cells which are involved in light touch perception. the next layer up is the stratum spinosum. which is a thick layer containing keratinocytes that are held together by desmodomes. above the spinosum is a thin layer called stratum granulosum which is composed of dying keratinocytes. the last layer is the stratum corneum, which is basically a thick layer of keratin, of variable thickness depending on the location on the body.
beneath the epidermis is the dermis, and the border between the two contains projections upwards from the dermis called papillary ridges and projections downwards from the epidermis called rete pegs. the dermis has two layers, a thin papillary layer and the reticular layer. the reticular layer makes up the bulk of the dermis and is made of dense irregular CT and is highly vascularized and innervated. inside the dermis are two types of pressure receptors- meissner's corpuscle senses light pressure in the papillary layer and is made from helically wound schwann cells around a nerve axon ending. pacinian corpuscles sense deep pressure in the reticular layer and are made of concentric schwann cell wrappings around the end of the axon.
questions
1. what are the 3 basic layers to the skin?
2. describe the epidermis.
3. describe the dermis.
4. describe the hypodermis.
5. what are the layers of the epidermis?
6. describe the stratum basale.
7. what are the cells that might appear in the stratum basale?
8. describe the stratum spinosum.
9. describe the stratum granulosum.
10. describe the stratum corneum.
11. what are the two layers of the dermis?
12. describe the papillary layer of the dermis.
13. describe the reticular layer of the dermis.
14. what is a meissner's corpuscle?
15. what is a pacinian corpuscle?
16. what is the smooth muscle strip associated with hair follicles?
17. describe the structure of a sweat gland.
18. describe the structure of a sebaceous gland.
answers
1. epidermis, dermis, hypodermis.
2. nonvascularized and minimally innervated, keratinized stratified squamous, made almost entirely of keratinocytes.
3. well vascularized and innervated, mostly dense irregular CT
4. mostly loose CT and adipose tissue.
5. stratum basale, spinosum, granulosum, corneum.
6. single layer of mitotically active cuboidal cells sitting on basement membrane.
7. melanocyte, which produces melanin. langerhans cell, which is an antigen presenting immune cell. merkel cell, involved in light touch sensation.
8. keratinocytes which are held together by extensive desmodomes. form a layer of variable thickness.
9. granular layer a few layers thick with dying keratinocytes.
10. keratinized layer of many dead keratinocytes, sometimes with a clear bottom portion called the stratum lucidum.
11. papillary layer, reticular layer
12. thin, undulating, with upward projections called dermal papillas and downward projections from epidermis called rete pegs.
13. thicker layer with dense irregular CT with elastin, highly vascularized and innervated.
14. touch sensor in dermal papillae. small, helical wound Schwann cells on an axon.
15. a deep pressure and vibration sensor in the deep dermis or hypodermis. large, with concentric layers of schwann cells.
16. arrector pili muscle
17. simple tubular gland extending deep into the dermis.
18. simple acinar gland off of hair follicles that produces sebum.
beneath the epidermis is the dermis, and the border between the two contains projections upwards from the dermis called papillary ridges and projections downwards from the epidermis called rete pegs. the dermis has two layers, a thin papillary layer and the reticular layer. the reticular layer makes up the bulk of the dermis and is made of dense irregular CT and is highly vascularized and innervated. inside the dermis are two types of pressure receptors- meissner's corpuscle senses light pressure in the papillary layer and is made from helically wound schwann cells around a nerve axon ending. pacinian corpuscles sense deep pressure in the reticular layer and are made of concentric schwann cell wrappings around the end of the axon.
questions
1. what are the 3 basic layers to the skin?
2. describe the epidermis.
3. describe the dermis.
4. describe the hypodermis.
5. what are the layers of the epidermis?
6. describe the stratum basale.
7. what are the cells that might appear in the stratum basale?
8. describe the stratum spinosum.
9. describe the stratum granulosum.
10. describe the stratum corneum.
11. what are the two layers of the dermis?
12. describe the papillary layer of the dermis.
13. describe the reticular layer of the dermis.
14. what is a meissner's corpuscle?
15. what is a pacinian corpuscle?
16. what is the smooth muscle strip associated with hair follicles?
17. describe the structure of a sweat gland.
18. describe the structure of a sebaceous gland.
answers
1. epidermis, dermis, hypodermis.
2. nonvascularized and minimally innervated, keratinized stratified squamous, made almost entirely of keratinocytes.
3. well vascularized and innervated, mostly dense irregular CT
4. mostly loose CT and adipose tissue.
5. stratum basale, spinosum, granulosum, corneum.
6. single layer of mitotically active cuboidal cells sitting on basement membrane.
7. melanocyte, which produces melanin. langerhans cell, which is an antigen presenting immune cell. merkel cell, involved in light touch sensation.
8. keratinocytes which are held together by extensive desmodomes. form a layer of variable thickness.
9. granular layer a few layers thick with dying keratinocytes.
10. keratinized layer of many dead keratinocytes, sometimes with a clear bottom portion called the stratum lucidum.
11. papillary layer, reticular layer
12. thin, undulating, with upward projections called dermal papillas and downward projections from epidermis called rete pegs.
13. thicker layer with dense irregular CT with elastin, highly vascularized and innervated.
14. touch sensor in dermal papillae. small, helical wound Schwann cells on an axon.
15. a deep pressure and vibration sensor in the deep dermis or hypodermis. large, with concentric layers of schwann cells.
16. arrector pili muscle
17. simple tubular gland extending deep into the dermis.
18. simple acinar gland off of hair follicles that produces sebum.
Wednesday, December 3, 2008
histology: vascular system
this lecture covers the circulatory system and the lymphatic system. the main types of blood vessels are reviewed (we covered this in organ systems already in much greater detail). arteries supply oxygenated blood to tissues and have three basic layers: the innermost layer is the tunica intima and has a squamous endothelium, subendothelial CT, and internal elastic lamina. the middle layer is the tunica media and has smooth muscle and external elastic lamina. the outermost layer is the tunica adventitia which has connective tissue that blends in with surrounding CT, with a network of blood vessels (vasa vasorum) and nerves (nervi vascularis). arterioles are the next level after arteries, which have a thicker smooth muscle tunica media layer which aids in their function, which is mainly to regulate blood flow to capillary beds. there are three types of capillaries which are distinguished by size and continuity of the endothelium: type 1 continuous, which have a tight endothelium which do not allow much leakage, type 2 fenestrated, which allow for some leakage and are present in the renal glomerulus, and type 3 discontinuous, which are much larger and have huge holes that allow for entire cells to pass through- found in the bone marrow, spleen, and liver. after the capillaries come the venules and veins, which are different from arteries in that they have no internal elastic lamina, a thinner tunica media, and rely on the contraction of skeletal muscle and a series of valves for blood flow back to the heart.
the lymphatic system is a sort of complementary system to the circulatory system in that it recirculates body fluids which have been picked up from the interstitial space outside of capillaries. it also functions in red blood cell production and destruction, aids in immunodefense (in the production and circulation of lymphocytes), and aids in fat absorption in the GI tract (think of the central lacteal in the lamina propria of the small intestine). there are several orders of lymphatic organization, the first of which is diffuse lymph tissue, which is just a scattering of lymphocytes in a general area, such as right underneath the epidermis in the airways or GI tract. next is nodular lymph tissue, which are more discrete aggregations of lymphocytes which might have germinal centers in the middle for profilerating new cells- such as the Peyer's patches in the ileum. next is a lymph node, which is an encapsulated "inline filter" for lymph vessels, a small container into which lymph gets poured in through many afferent lymphatic vessels, filtered through the subcapsular and medullary sinuses, and poured back out through a larger efferent lymphatic vessel.
finally, we get to the lymph organs, which are large scale lymph and blood filtering factories. first is the spleen, the functional part of which is called the splenic pulp, which comes in two varieties- red and white. the red is the bulk of the spleen and is filled with RBC's, and white pulp are little islands of lymphocytes that are found alongside blood vessels. the tonsils are another lymph organ, consisting of a series of lymphatic tissue masses covered by a stratified squamous epithelium which is thrown into "crypts". the thymus is the third and last lymph organ, and is a bi-lobed organ beneath the sternum in which t-lymphocytes are trained to differentiate self from non-self.
questions
1. what are the three basic layers to arteries?
2. describe the tunica intima layer of arteries.
3. describe the tunica media layer of arteries.
4. describe the tunica adventitia layer of arteries.
5. what is an arteriole?
6. what are three major differences between veins and arteries?
7. what is a venule?
8. what are the three types of capillaries?
9. describe type I capillaries.
10. describe type II capillaries.
11. describe type III capillaries.
12. what are the main functions of the lymphatic system?
13. describe lymphatic vessels.
14. what are the two types of lymphoid tissue?
15. describe diffuse lymphoid tissue.
16. describe nodular lymphoid tissue.
17. what are the four examples of lymph organs?
18. describe the structure of a lymph node.
19. what is the flow through a lymph vessel?
20. describe the structure of the spleen.
21. what is the thymus?
22. describe the structure of the tonsils.
answers
1. tunica intima, tunica media, tunica adventitia.
2. tunica intima is the innermost layer of an artery and contains squamous endothelium, sub endothelial CT, and internal elastic lamina.
3. tunica media is the middle, thickest layer that contains smooth muscle with elastin.
4. tunica adventitia is the outermost layer containing CT with a network of blood vessels (vasa vasorum) and nerves (nervi vascularis)
5. an artery with a luminal diameter of less than 100um that plays a role in distributing and controlling entry of blood into capillary beds.
6. no internal elastic lamina, relatively thin tunica media, and endothelium is thrown into valves to prevent backflow.
7. a vein with a luminal diameter of less than 200um.
8. type 1 continuous, type 2 fenestrated, type 3 discontinuous.
9. the most common capillary in the body, the endothelium is held tightly together and is relatively leak proof.
10. small holes in endothelium allow some leakage, seen in glomerulus, exocrine ducts, choroid plexus.
11. larger (up to 30um) diameter with large holes in endothelium that allow entire cells to pass, seen in liver, bone marrow, spleen.
12. recirculation of body fluids, defense, hematopoeisis (adding lymphocytes), recycling RBC's (spleen), absorption of fat in GI tract. recirculate blood in defense of fat recycling.
13. vessels that gather and remove excess tissue fluid from capillaries and circulate back into venous system. rely on skeletal muscle and valve system for pumping (much like veins).
14. diffuse and nodular
15. scattering of lymphocytes; often associated with epithelial linings of GI tract and respiratory airways.
16. semi discrete (but unencapsulated) mass of lymphocytes, sometimes with a germinal center where new cells proliferating.
17. lymph nodes, spleen, tonsils, thymus.
18. encapsulated mass of lymph nodules that serves as an in line filter (for lymph) with multiple afferent "feeder" lines and one or two efferent "drainer" lines.
19. afferent lymph vessel, subcapsular sinus, medullary sinus, efferent lymphatic vessel.
20. inline filter (for blood) with two types of "pulp" in the parenchyma: red pulp is the bulk of the spleen and has masses of RBC's, white pulp is small lymphocytes islands associated with blood vessels.
21. a bilobed t-lymphocyte manufacturing center underneath the sternum
22. series of masses of lymphoid tissue with stratified squamous epithelium thrown into crypts that cover aggregations of nodules.
the lymphatic system is a sort of complementary system to the circulatory system in that it recirculates body fluids which have been picked up from the interstitial space outside of capillaries. it also functions in red blood cell production and destruction, aids in immunodefense (in the production and circulation of lymphocytes), and aids in fat absorption in the GI tract (think of the central lacteal in the lamina propria of the small intestine). there are several orders of lymphatic organization, the first of which is diffuse lymph tissue, which is just a scattering of lymphocytes in a general area, such as right underneath the epidermis in the airways or GI tract. next is nodular lymph tissue, which are more discrete aggregations of lymphocytes which might have germinal centers in the middle for profilerating new cells- such as the Peyer's patches in the ileum. next is a lymph node, which is an encapsulated "inline filter" for lymph vessels, a small container into which lymph gets poured in through many afferent lymphatic vessels, filtered through the subcapsular and medullary sinuses, and poured back out through a larger efferent lymphatic vessel.
finally, we get to the lymph organs, which are large scale lymph and blood filtering factories. first is the spleen, the functional part of which is called the splenic pulp, which comes in two varieties- red and white. the red is the bulk of the spleen and is filled with RBC's, and white pulp are little islands of lymphocytes that are found alongside blood vessels. the tonsils are another lymph organ, consisting of a series of lymphatic tissue masses covered by a stratified squamous epithelium which is thrown into "crypts". the thymus is the third and last lymph organ, and is a bi-lobed organ beneath the sternum in which t-lymphocytes are trained to differentiate self from non-self.
questions
1. what are the three basic layers to arteries?
2. describe the tunica intima layer of arteries.
3. describe the tunica media layer of arteries.
4. describe the tunica adventitia layer of arteries.
5. what is an arteriole?
6. what are three major differences between veins and arteries?
7. what is a venule?
8. what are the three types of capillaries?
9. describe type I capillaries.
10. describe type II capillaries.
11. describe type III capillaries.
12. what are the main functions of the lymphatic system?
13. describe lymphatic vessels.
14. what are the two types of lymphoid tissue?
15. describe diffuse lymphoid tissue.
16. describe nodular lymphoid tissue.
17. what are the four examples of lymph organs?
18. describe the structure of a lymph node.
19. what is the flow through a lymph vessel?
20. describe the structure of the spleen.
21. what is the thymus?
22. describe the structure of the tonsils.
answers
1. tunica intima, tunica media, tunica adventitia.
2. tunica intima is the innermost layer of an artery and contains squamous endothelium, sub endothelial CT, and internal elastic lamina.
3. tunica media is the middle, thickest layer that contains smooth muscle with elastin.
4. tunica adventitia is the outermost layer containing CT with a network of blood vessels (vasa vasorum) and nerves (nervi vascularis)
5. an artery with a luminal diameter of less than 100um that plays a role in distributing and controlling entry of blood into capillary beds.
6. no internal elastic lamina, relatively thin tunica media, and endothelium is thrown into valves to prevent backflow.
7. a vein with a luminal diameter of less than 200um.
8. type 1 continuous, type 2 fenestrated, type 3 discontinuous.
9. the most common capillary in the body, the endothelium is held tightly together and is relatively leak proof.
10. small holes in endothelium allow some leakage, seen in glomerulus, exocrine ducts, choroid plexus.
11. larger (up to 30um) diameter with large holes in endothelium that allow entire cells to pass, seen in liver, bone marrow, spleen.
12. recirculation of body fluids, defense, hematopoeisis (adding lymphocytes), recycling RBC's (spleen), absorption of fat in GI tract. recirculate blood in defense of fat recycling.
13. vessels that gather and remove excess tissue fluid from capillaries and circulate back into venous system. rely on skeletal muscle and valve system for pumping (much like veins).
14. diffuse and nodular
15. scattering of lymphocytes; often associated with epithelial linings of GI tract and respiratory airways.
16. semi discrete (but unencapsulated) mass of lymphocytes, sometimes with a germinal center where new cells proliferating.
17. lymph nodes, spleen, tonsils, thymus.
18. encapsulated mass of lymph nodules that serves as an in line filter (for lymph) with multiple afferent "feeder" lines and one or two efferent "drainer" lines.
19. afferent lymph vessel, subcapsular sinus, medullary sinus, efferent lymphatic vessel.
20. inline filter (for blood) with two types of "pulp" in the parenchyma: red pulp is the bulk of the spleen and has masses of RBC's, white pulp is small lymphocytes islands associated with blood vessels.
21. a bilobed t-lymphocyte manufacturing center underneath the sternum
22. series of masses of lymphoid tissue with stratified squamous epithelium thrown into crypts that cover aggregations of nodules.
Tuesday, December 2, 2008
histology: urinary system
this unit provided a brief histological overview of the kidneys and the tubular architecture of the urinary system. the basic function of the kidneys is to filter the blood and excrete waste through the urine, which leaves the kidney via the ureter, is pooled in the bladder, then goes from the bladder to the body's exterior by means of the urethra. inside the kidney itself there is an outer layer called the cortex and an inner layer called the medulla, which contains triangular shaped lobes called medullary pyramids. the pyramids collect urine at their tips, called area cribosa, into the calyces, which drain into the renal sinuses, renal pelvis, and out to the ureter. the kidney is filled with functional tubular units called the nephron, of which there are two types: juxtamedullary and cortical, depending on their location.
the site of filtration of blood occurs at the glomerulus, which is a ball of type 2 fenestrated capillaries inside a Bowman's capsule. the Bowman's capsule is similar to a pericardium or pleura in that it has a visceral and parietal layer and a space in between; in this case, the visceral layer is made up of the layer of podocytes that encase the ball of capillaries and provide an extra filtration layer, outside of which there is the bowman's space, and then the parietal bowman's capsule. the blood supply to the ball of capillaries comes from the afferent arteriole and leaves through the efferent arteriole; this end of the glomerulus is called the vascular pole. on the other side of the glomerulus is the urinary pole, which collects the filtrate from the blood into the proximal tubule, which is a convoluted tubule made of simple cuboidal epithelium with extensive apical microvilli. this tubule descends into the medullary region and becomes the loop of Henle, which is thin and squamous on the way down and thick and cuboidal on the way up. this turns into the distal convoluted tubule, which comes back to the glomerulus to form the juxtamedullary complex, which is a junction of the distal tubule and the efferent arteriole, with a group of cells called the macula densa in between. the distal tubule then dumps into a collecting duct, which empties into the papillary ducts that empty into the area cribrosa of the medullary pyramids, and out the body as covered above.
the blood flow in and out of the kidney is as follows: the visceral abdominal aorta supplies the blood to the renal artery, which branches into the interlobular arteries, which branch into the arcuate arteries, which branch into the interlobular arteries, which branch into the intralobular arteries, which turn into afferent arterioles and enter the glomerulus. the blood is filtered in the capillaries in the glomerulus, then flows out through the efferent arteriole, then enters peritubular capillaries, which are small capillaries that run alongside nephron tubules and are the link between the arteries and veins in the kidneys. from the peritubular capillaries, blood flows into veins and exits in the opposite order: intralobular, interlobular, etc etc.
some details about the epithelium of the plumbing of the urinary system: there is transitional epithelium basically from the ureter to the end of the urethra, which switches to non-keratinized stratified squamous. the muscularis externa of the ureter and urethra has opposite layers than other tubes of the body in that has an inner longitudinal and outer circular layer. the urinary bladder has a thick and choatic muscularis externa.
questions
1. what are four functions of the urinary system?
2. describe the anatomy of the kidney.
3. describe the blood flow in and out of the kidney.
4. what are the two types of nephrons?
5. describe the anatomy of a glomerulus.
6. what are the two poles in a glomerulus?
7. what is the glomelular membrane composed of?
8. describe the proximal tubule.
9. describe the loop of Henle.
10. describe the distal tubule.
11. what is a juxtaglomerular apparatus?
12. describe the collecting ducts.
13. describe juxtaglomerular cells.
14. what are peritubular capillaries?
15. describe the ureter.
16. describe the urinary bladder.
17. describe the epithelium of the urethra.
18. describe the muscularis externa of the urethra.
answers
1. chemically balance the blood, remove wastes, regulate blood pressure, and regulate red blood cell production.
2. kidneys have an outer layer called cortex and inner layer called medulla. in the medulla there are medullary pyramids from which urine is collected from the tips (area cribrosa) to the minor and major calyces, which converge into the renal sinuses, which converge into the renal pelvis, which leads out to the ureter.
3. renal artery to interlobar artery to arcuate artery to interlobular artery to intralobular artery to afferent arteriole to glomelular capsule to intralobular vein to interlobular vein to arcuate vein to interlobar vein to renal vein.
4. cortical nephrons and juxtamedullary nephrons.
5. 1-20 type II capillaries held together by a mesangium, encased in podocytes which make up the visceral Bowman's capsule, outside of which is the Bowman's space, and then the parietal Bowman's capsule.
6. vascular pole contains the afferent and efferent arterioles. urinary pole is on the other end of the glomerulus, where the proximal tubule starts.
7. type II capillary endothelium, endothelial basement membrane, podocyte basement membrane, podocyte, occasional mesangial cell.
8. long, convoluted, does most of the absorption, simple cuboidal with extensive apical microvilli.
9. has a thin, squamous descending section and a thick, ascending, cuboidal section.
10. simple suboidal, no microvilli. convolutes and feeds into a collecting duct.
11. the junction between a distal tubule and a vascular pole, with a macula densa in between
12. a large diameter tube that is the common collecting point for a number of nephrons, and merges into papillary ducts to the area cribrosa. simple cuboidal with rounded apical surfaces.
13. modified smooth muscle cells that secrete renin, which catalyzes formation of angiotensin-- regulates blood pressure.
14. the capillaries found of the back sides of nephric tubules and serve as points for absorption, the link between arterial and venous blood vasculature.
15. long muscular tube from renal pelvis to bladder with transitional epithelium and lamina propria (but no muscularis mucosa) muscularis externa has "reversed" layers -- inner longitudinal outer circular.
16. distensible sac with transitional epithelium and lamina propria but no muscularis mucosa. muscularis externa thick and chaotic.
17. PSC epithelium, near bladder is more transitional, near exterior is more non keratinzed stratified squamous. muscularis externa has inner longitudinal, outer circular.
the site of filtration of blood occurs at the glomerulus, which is a ball of type 2 fenestrated capillaries inside a Bowman's capsule. the Bowman's capsule is similar to a pericardium or pleura in that it has a visceral and parietal layer and a space in between; in this case, the visceral layer is made up of the layer of podocytes that encase the ball of capillaries and provide an extra filtration layer, outside of which there is the bowman's space, and then the parietal bowman's capsule. the blood supply to the ball of capillaries comes from the afferent arteriole and leaves through the efferent arteriole; this end of the glomerulus is called the vascular pole. on the other side of the glomerulus is the urinary pole, which collects the filtrate from the blood into the proximal tubule, which is a convoluted tubule made of simple cuboidal epithelium with extensive apical microvilli. this tubule descends into the medullary region and becomes the loop of Henle, which is thin and squamous on the way down and thick and cuboidal on the way up. this turns into the distal convoluted tubule, which comes back to the glomerulus to form the juxtamedullary complex, which is a junction of the distal tubule and the efferent arteriole, with a group of cells called the macula densa in between. the distal tubule then dumps into a collecting duct, which empties into the papillary ducts that empty into the area cribrosa of the medullary pyramids, and out the body as covered above.
the blood flow in and out of the kidney is as follows: the visceral abdominal aorta supplies the blood to the renal artery, which branches into the interlobular arteries, which branch into the arcuate arteries, which branch into the interlobular arteries, which branch into the intralobular arteries, which turn into afferent arterioles and enter the glomerulus. the blood is filtered in the capillaries in the glomerulus, then flows out through the efferent arteriole, then enters peritubular capillaries, which are small capillaries that run alongside nephron tubules and are the link between the arteries and veins in the kidneys. from the peritubular capillaries, blood flows into veins and exits in the opposite order: intralobular, interlobular, etc etc.
some details about the epithelium of the plumbing of the urinary system: there is transitional epithelium basically from the ureter to the end of the urethra, which switches to non-keratinized stratified squamous. the muscularis externa of the ureter and urethra has opposite layers than other tubes of the body in that has an inner longitudinal and outer circular layer. the urinary bladder has a thick and choatic muscularis externa.
questions
1. what are four functions of the urinary system?
2. describe the anatomy of the kidney.
3. describe the blood flow in and out of the kidney.
4. what are the two types of nephrons?
5. describe the anatomy of a glomerulus.
6. what are the two poles in a glomerulus?
7. what is the glomelular membrane composed of?
8. describe the proximal tubule.
9. describe the loop of Henle.
10. describe the distal tubule.
11. what is a juxtaglomerular apparatus?
12. describe the collecting ducts.
13. describe juxtaglomerular cells.
14. what are peritubular capillaries?
15. describe the ureter.
16. describe the urinary bladder.
17. describe the epithelium of the urethra.
18. describe the muscularis externa of the urethra.
answers
1. chemically balance the blood, remove wastes, regulate blood pressure, and regulate red blood cell production.
2. kidneys have an outer layer called cortex and inner layer called medulla. in the medulla there are medullary pyramids from which urine is collected from the tips (area cribrosa) to the minor and major calyces, which converge into the renal sinuses, which converge into the renal pelvis, which leads out to the ureter.
3. renal artery to interlobar artery to arcuate artery to interlobular artery to intralobular artery to afferent arteriole to glomelular capsule to intralobular vein to interlobular vein to arcuate vein to interlobar vein to renal vein.
4. cortical nephrons and juxtamedullary nephrons.
5. 1-20 type II capillaries held together by a mesangium, encased in podocytes which make up the visceral Bowman's capsule, outside of which is the Bowman's space, and then the parietal Bowman's capsule.
6. vascular pole contains the afferent and efferent arterioles. urinary pole is on the other end of the glomerulus, where the proximal tubule starts.
7. type II capillary endothelium, endothelial basement membrane, podocyte basement membrane, podocyte, occasional mesangial cell.
8. long, convoluted, does most of the absorption, simple cuboidal with extensive apical microvilli.
9. has a thin, squamous descending section and a thick, ascending, cuboidal section.
10. simple suboidal, no microvilli. convolutes and feeds into a collecting duct.
11. the junction between a distal tubule and a vascular pole, with a macula densa in between
12. a large diameter tube that is the common collecting point for a number of nephrons, and merges into papillary ducts to the area cribrosa. simple cuboidal with rounded apical surfaces.
13. modified smooth muscle cells that secrete renin, which catalyzes formation of angiotensin-- regulates blood pressure.
14. the capillaries found of the back sides of nephric tubules and serve as points for absorption, the link between arterial and venous blood vasculature.
15. long muscular tube from renal pelvis to bladder with transitional epithelium and lamina propria (but no muscularis mucosa) muscularis externa has "reversed" layers -- inner longitudinal outer circular.
16. distensible sac with transitional epithelium and lamina propria but no muscularis mucosa. muscularis externa thick and chaotic.
17. PSC epithelium, near bladder is more transitional, near exterior is more non keratinzed stratified squamous. muscularis externa has inner longitudinal, outer circular.
Saturday, November 29, 2008
histology: digestive system
this lecture provided a histological perspective on the different sections of the digestive system, focusing on tissue and cell types. the digestive system is introduced as one long tube which starts in the pharynx, becomes the esophagus, stomach, small intestine, large intestine, then rectum. within all of these sections, there are generally four different layers: the mucosa is the innermost layer and contains the epithelium (either stratified squamous or simple columnar), a loose or reticular CT lamina propria, and a layer of muscle named the muscularis mucosa. beneath this is the submucosa, which contains blood vessels and nerves (and in the small intestine, the meissner's plexus). beneath this is the muscularis externa, which is generally composed of an inner circular layer, middle plexus of ganglia ("myenteric" plexus), and outer longitudinal layer. finally, on the outside of the tube is the serosa (or adventitia in some places, such as the esophagus above the diaphragm), which is made up of connective tissue and mesothelium. all of the sections of the digestive system are made up of variants of these four layers depending on location and function.
the first section, the esophagus, is unique in that its epithelia is made up of non-keratinized stratified squamous (presumably to deal with the abrasion of food coming in, and non-keratinized because waterproofing isn't an issue), which is thrown into esophageal glands that begin the lubricating process. the muscularis layer is also unique in that the top part of the esophagus is mainly skeletal muscle, gradually blends with smooth muscle in the middle, and by the bottom is mainly smooth muscle. the esophagus ends in the esophageal-cardiac junction, where the epithelial layer transitions from the non-keratinized stratified of the esophagus to the simple columnar of the stomach.
the stomach has four sections, from top to bottom: the cardiac, fundic, body, pyloric regions. the mucosa of the stomach is thrown into gastric glands, which contain specialized secretory cells which aid in digestion: surface mucous cells and mucous neck cells secrete mucous near the tops and bottoms of the glands, respectively. parietal cells secrete HCl near the tops of the glands, and chief cells secrete pepsinogen near the base of the glands. the muscularis of the stomach is also unique in that it has an inner oblique layer, middle circular, and outer longitudinal layer. the fundus is the most representative region of the stomach, and the other three regions are variations on this region. for example, the epithelia in both the cardiac and pyloric regions contain only mucous cells, and the muscularis layers are tightened into the cardiac and pyloric sphincters on either end.
after the stomach comes the small intestine, which is divided into three regions, the duodenum, jejunum (the most representative region), and ileum. the intestinal mucosa is unique in that it is folded into large intestinal glands called "Krypts of Lieberkuhn", covered with columnar absorptive/secretory cells called enterocytes, with goblet cells scattered throughout. also present in the epithelium are enteroendocrine cells, which secrete hormone like substances, as well as Paneth cells, which secrete lysozymes to regulate the bacterial flora in the gut. the lamina propria of the intestine is well vascularized with type 2 fenestrated capillaries, with occasional lymph nodes called Peyer's Patches. additionally, there is often a "central lacteal" inside the villi, which is a large lymph vessel that aids in absorption of larger molecules. the muscularis of the small intestine generally contains an inner circular layer, followed by a nerve "net" called the myenteric plexus, followed by an outer longitudinal muscle layer.
the large intestine is similar to the small intestine, the main differences being: more goblet cells, lymph rich, but no microvilli, paneth cells, or enteroendocrine cells. it has two main sections, the colon and the rectum, and at the "end of the line", the rectal-anal junction, there are four notable changes: the transition from the simple columnar absorptive cells of the small intestine to the non-keratinized stratified squamous of the rectum, the patchy muscularis mucosa, the huge blood vessels in the submucosa, and the presence of skeletal muscle in the muscularis externa. (notice how this is similar to the esophagus)
the role of the pancreas and liver in digestion is then looked at: the pancreas is a mostly exocrine gland which secretes from compound acinar glands a variety of enzymes-- carboxypeptidase, chymotrypsinogen, trypsinogen for digestion of proteins, amylase for digestion of carbohydrates, lipase for digestion of lipids, and bicarbonate to neutralize the acidity from gastric digestion. it also functions as an endocrine gland with its "Islets of Langerhans", which contain alpha, beta, and delta cells which release glucagon, insulin, and somatostatin, respectively. the liver also functions as both an endocrine / exocrine gland which aids in digestion by releasing bile for digestion of fats (exocrine) and filtering and adding to blood (endocrine). the liver has many functions, such as processing of glycogen, fetal blood cell production, production of blood clotting factors, and detoxification of the blood.
the basic cell type of the liver is called the hepatocyte, and they are arranged in roughly hexagonally shaped functional units called "lobules". on the borders of the lobules, on roughly every other corner of the hexagon, are "portal triads" which contain hepatic portal veins (which supply oxygen poor, nutrient rich blood to the liver from the intestine), hepatic arteries (supplying fresh blood to the liver), and bile ducts. in the center of the lobules are "central veins" which carry away deoxygenated blood. the last aspect of the liver that's looked at is the liver acinus theory, which states that blood flows from the portal triad laterally to the adjacent central veins, forming a diamond shaped functional unit overlayed on two lobules.
questions
1. what are the four primary layers in the entire digestive system?
2. what is the mucosa composed of?
3. what is in the submucosa?
4. what is the muscularis composed of?
5. what is the serosa composed of?
esophagus
6. describe the mucosa of the esophagus.
7. describe the muscularis of the esophagus.
8. describe the outer wall of the esophagus.
9. what is the esophageal-cardiac junction?
stomach- surface mucosa, mucosa neck, chief, parietal,
10. what are the four parts to the stomach?
11. describe the mucosa of the stomach.
12. what are some other cells that function in the mucosa of the stomach?
13. describe the muscularis externa of the stomach.
14. how does the cardiac region of the stomach differ from the body region?
15. how does the pyloric region of the stomach differ from the body region?
small intestine- lieberkuhn, enterocytes, paneth, meissner's, peyer's patch, brunner's
16. what are the three parts to the small intestine?
17. describe the mucosa of the small intestine.
18. what is unique about the surface of the mucosa of the small intestine?
19. what are the crypts of Lieberkuhn?
20. which digestive enzymes are secreted by the pancreas to aid in digestion in the small intestine?
21. what is secreted from the liver to help in digestion in the small intestine?
22. what are some of the cells in the mucosal epithelium of the small intestine?
23. describe the lamina propria of the small intestine.
24. describe the submucosa of the small intestine.
25. describe the myenteric plexus and what role it plays.
26. the serosa of the small intestine is the...
27. what are brunner's glands and what do they do? where are they found?
28. what are some distinguishing characteristics of the ileum?
large intestine-
29. describe the mucosa of the large intestine.
30. what are the four characteristics of the rectal-anal junction?
accessory glands- salivary glands, pancreas, liver,
31. what are the three types of salivary glands and what do they secrete?
32. describe the exocrine function of the pancreas.
33. describe the endocrine function of the pancreas.
34. name five major functions of the liver.
35. describe how the liver operates both as an exocrine and endocrine gland.
36. what is the hepatic portal vein?
37. what is the hepatic artery?
38. what type of capillaries are in the liver?
39. what is the basic cell type in the liver and what are they assembled into?
40. describe the architecture of the lobule.
41. what is the liver acinus theory? why is it the most likely scheme of blood flow in the liver?
answers
1. mucosa, submucosa, muscularis, serosa
2. epithelium (mostly simple columnar), lamina propria, muscularis mucosa
3. connective tissue with blood vessels and nerves, sometimes a submucosal plexus (meissner's)
4. inner circular layer of smooth muscle, middle plexus of ganglia (myenteric/auerbach's), outer longitudinal smooth muscle
5. CT, mesothelium
6. non-keratinzed stratified squamous epithelium, has esophageal glands for lubrication.
7. upper 1/3 made of skeletal muscle, middle 1/3 mix of skeletal and smooth muscle, lower 1/3 smooth muscle.
8. has adventitia, serosa seen only after tube penetrates diaphragm.
9. the end of the esophagus, an abrupt change from stratified squamous to simple columnar epithelium.
10. cardiac, fundus, body, pylorus
11. simple columnar epithelium with gastric glands for digestion, lamina propria which is richly vascularized, loose / reticular CT.
12. surface mucous cells, mucous neck cells secrete mucous on surface and at base of gastric pits. parietal cells secrete HCl at top of gland proper. chief cells secrete pepsinogen near base of gland.
13. inner oblique, middle circular, outer longitudinal. thickened at either end of stomach to form cardiac and pyloric sphincter.
14. cardiac region glands only have mucous cells, and there is an abrupt change from the esophagus.
15. pyloric region glands only have mucous cells. glands branch more and have deeper pits.
16. duodenum, jejunum, ileum.
17. simple columnar epithelium thrown into glandular tubes called intestinal glands (crypts of Lieberkuhn) and projections called villi.
18. they have a striated border formed from microvilli.
19. intestinal glands that both secrete and absorb.
20. trypsinogen, chymotrypsinogen, carboxypeptidase (for protein), amylase (for carbohydrates), lipase (for lipids)
21. bile salts (for lipids)
22. primarily composed of enterocytes which are columnar absorptive cells with microvilli, with mucous secreting goblet cells throughout, as well as enteroendocrine cells which are at the base of the glands and secrete hormone like substances, and paneth cells which secretes lysozyme to control bacterial flora.
23. well vascularized, type II capillaries, may have a central lacteal for absorption of larger molecules, may have lymph nodules called Peyer's patches.
24. may have a meissner's plexus, which assists in regulating secretion and blood flow.
25. a nerve net in the muscularis layer which helps coordinate peristaltic contractions of muscularis externa.
26. visceral peritoneum.
27. in the submucosa of the duodenum, secretes alkaline-mucoid material and urogastrone.
28. greatest amount of "GALT", Peyer's patches, fewer villi and more goblet cells.
29. simple columnar epithelia with intestinal glands but no villi. abundant goblet cells and lymph rich lamina propria, but no entero-endocrine or paneth cells.
30. epithelial transition from simple columnar to non-keratinized stratified squamous, patchy muscularis mucosa, huge blood vessels in submucosa, skeletal muscle in muscularis externa. transition, patchy, blood, skeletal.
31. parotid secretes mainly serous, submandibular secretes a mixture of mucous and serous, and sublingual secretes mostly mucous.
32. the pancreas' function is mainly to serve as an exocrine gland which secrete digestive enzymes (see question 20), composed of compound acinar glands. it also secretes alkaline bicarbonate in order to neutralize the acidity from gastric digestion.
33. 2% of the pancreas is used for endocrine function, in the form of "islets of langerhans" which are clumped glands which consist of alpha, beta, and delta cells which secrete glucagon, insulin, and somatostatin, respectively.
34. fetal hematopoesis (before shifting to bone marrow), glucagon processing, plasma protein production (such as clotting factors), bile production, and detoxification. blood, glucagon, clotting, bile, detox. detox clotting blood into a bile of glucagon.
35. exocrine because it dumps bile into the intestine, endocrine because it filters blood and adds to it.
36. the vein that brings oxygen poor but potentially nutrient rich blood into the liver from the GI tract.
37. the artery that brings fresh blood to the liver itself.
38. type three discontinuous.
39. basic cell type is the hepatocyte and they are arranged into lobules.
40. hexagonal shaped cell with a large central vein in the middle and a trio of vessels at every other corner of the border of the cell, called the portal area: containing hepatic portal vein (question 36), hepatic artery (question 37), and bile duct.
41. the liver acinus theory of blood flow says that blood flows laterally from the portal areas to the adjacent central vein (creating a diamond shaped functional unit overlayed on top of two lobules). this theory is backed up by the patterns of degradation during liver poisoning.
the first section, the esophagus, is unique in that its epithelia is made up of non-keratinized stratified squamous (presumably to deal with the abrasion of food coming in, and non-keratinized because waterproofing isn't an issue), which is thrown into esophageal glands that begin the lubricating process. the muscularis layer is also unique in that the top part of the esophagus is mainly skeletal muscle, gradually blends with smooth muscle in the middle, and by the bottom is mainly smooth muscle. the esophagus ends in the esophageal-cardiac junction, where the epithelial layer transitions from the non-keratinized stratified of the esophagus to the simple columnar of the stomach.
the stomach has four sections, from top to bottom: the cardiac, fundic, body, pyloric regions. the mucosa of the stomach is thrown into gastric glands, which contain specialized secretory cells which aid in digestion: surface mucous cells and mucous neck cells secrete mucous near the tops and bottoms of the glands, respectively. parietal cells secrete HCl near the tops of the glands, and chief cells secrete pepsinogen near the base of the glands. the muscularis of the stomach is also unique in that it has an inner oblique layer, middle circular, and outer longitudinal layer. the fundus is the most representative region of the stomach, and the other three regions are variations on this region. for example, the epithelia in both the cardiac and pyloric regions contain only mucous cells, and the muscularis layers are tightened into the cardiac and pyloric sphincters on either end.
after the stomach comes the small intestine, which is divided into three regions, the duodenum, jejunum (the most representative region), and ileum. the intestinal mucosa is unique in that it is folded into large intestinal glands called "Krypts of Lieberkuhn", covered with columnar absorptive/secretory cells called enterocytes, with goblet cells scattered throughout. also present in the epithelium are enteroendocrine cells, which secrete hormone like substances, as well as Paneth cells, which secrete lysozymes to regulate the bacterial flora in the gut. the lamina propria of the intestine is well vascularized with type 2 fenestrated capillaries, with occasional lymph nodes called Peyer's Patches. additionally, there is often a "central lacteal" inside the villi, which is a large lymph vessel that aids in absorption of larger molecules. the muscularis of the small intestine generally contains an inner circular layer, followed by a nerve "net" called the myenteric plexus, followed by an outer longitudinal muscle layer.
the large intestine is similar to the small intestine, the main differences being: more goblet cells, lymph rich, but no microvilli, paneth cells, or enteroendocrine cells. it has two main sections, the colon and the rectum, and at the "end of the line", the rectal-anal junction, there are four notable changes: the transition from the simple columnar absorptive cells of the small intestine to the non-keratinized stratified squamous of the rectum, the patchy muscularis mucosa, the huge blood vessels in the submucosa, and the presence of skeletal muscle in the muscularis externa. (notice how this is similar to the esophagus)
the role of the pancreas and liver in digestion is then looked at: the pancreas is a mostly exocrine gland which secretes from compound acinar glands a variety of enzymes-- carboxypeptidase, chymotrypsinogen, trypsinogen for digestion of proteins, amylase for digestion of carbohydrates, lipase for digestion of lipids, and bicarbonate to neutralize the acidity from gastric digestion. it also functions as an endocrine gland with its "Islets of Langerhans", which contain alpha, beta, and delta cells which release glucagon, insulin, and somatostatin, respectively. the liver also functions as both an endocrine / exocrine gland which aids in digestion by releasing bile for digestion of fats (exocrine) and filtering and adding to blood (endocrine). the liver has many functions, such as processing of glycogen, fetal blood cell production, production of blood clotting factors, and detoxification of the blood.
the basic cell type of the liver is called the hepatocyte, and they are arranged in roughly hexagonally shaped functional units called "lobules". on the borders of the lobules, on roughly every other corner of the hexagon, are "portal triads" which contain hepatic portal veins (which supply oxygen poor, nutrient rich blood to the liver from the intestine), hepatic arteries (supplying fresh blood to the liver), and bile ducts. in the center of the lobules are "central veins" which carry away deoxygenated blood. the last aspect of the liver that's looked at is the liver acinus theory, which states that blood flows from the portal triad laterally to the adjacent central veins, forming a diamond shaped functional unit overlayed on two lobules.
questions
1. what are the four primary layers in the entire digestive system?
2. what is the mucosa composed of?
3. what is in the submucosa?
4. what is the muscularis composed of?
5. what is the serosa composed of?
esophagus
6. describe the mucosa of the esophagus.
7. describe the muscularis of the esophagus.
8. describe the outer wall of the esophagus.
9. what is the esophageal-cardiac junction?
stomach- surface mucosa, mucosa neck, chief, parietal,
10. what are the four parts to the stomach?
11. describe the mucosa of the stomach.
12. what are some other cells that function in the mucosa of the stomach?
13. describe the muscularis externa of the stomach.
14. how does the cardiac region of the stomach differ from the body region?
15. how does the pyloric region of the stomach differ from the body region?
small intestine- lieberkuhn, enterocytes, paneth, meissner's, peyer's patch, brunner's
16. what are the three parts to the small intestine?
17. describe the mucosa of the small intestine.
18. what is unique about the surface of the mucosa of the small intestine?
19. what are the crypts of Lieberkuhn?
20. which digestive enzymes are secreted by the pancreas to aid in digestion in the small intestine?
21. what is secreted from the liver to help in digestion in the small intestine?
22. what are some of the cells in the mucosal epithelium of the small intestine?
23. describe the lamina propria of the small intestine.
24. describe the submucosa of the small intestine.
25. describe the myenteric plexus and what role it plays.
26. the serosa of the small intestine is the...
27. what are brunner's glands and what do they do? where are they found?
28. what are some distinguishing characteristics of the ileum?
large intestine-
29. describe the mucosa of the large intestine.
30. what are the four characteristics of the rectal-anal junction?
accessory glands- salivary glands, pancreas, liver,
31. what are the three types of salivary glands and what do they secrete?
32. describe the exocrine function of the pancreas.
33. describe the endocrine function of the pancreas.
34. name five major functions of the liver.
35. describe how the liver operates both as an exocrine and endocrine gland.
36. what is the hepatic portal vein?
37. what is the hepatic artery?
38. what type of capillaries are in the liver?
39. what is the basic cell type in the liver and what are they assembled into?
40. describe the architecture of the lobule.
41. what is the liver acinus theory? why is it the most likely scheme of blood flow in the liver?
answers
1. mucosa, submucosa, muscularis, serosa
2. epithelium (mostly simple columnar), lamina propria, muscularis mucosa
3. connective tissue with blood vessels and nerves, sometimes a submucosal plexus (meissner's)
4. inner circular layer of smooth muscle, middle plexus of ganglia (myenteric/auerbach's), outer longitudinal smooth muscle
5. CT, mesothelium
6. non-keratinzed stratified squamous epithelium, has esophageal glands for lubrication.
7. upper 1/3 made of skeletal muscle, middle 1/3 mix of skeletal and smooth muscle, lower 1/3 smooth muscle.
8. has adventitia, serosa seen only after tube penetrates diaphragm.
9. the end of the esophagus, an abrupt change from stratified squamous to simple columnar epithelium.
10. cardiac, fundus, body, pylorus
11. simple columnar epithelium with gastric glands for digestion, lamina propria which is richly vascularized, loose / reticular CT.
12. surface mucous cells, mucous neck cells secrete mucous on surface and at base of gastric pits. parietal cells secrete HCl at top of gland proper. chief cells secrete pepsinogen near base of gland.
13. inner oblique, middle circular, outer longitudinal. thickened at either end of stomach to form cardiac and pyloric sphincter.
14. cardiac region glands only have mucous cells, and there is an abrupt change from the esophagus.
15. pyloric region glands only have mucous cells. glands branch more and have deeper pits.
16. duodenum, jejunum, ileum.
17. simple columnar epithelium thrown into glandular tubes called intestinal glands (crypts of Lieberkuhn) and projections called villi.
18. they have a striated border formed from microvilli.
19. intestinal glands that both secrete and absorb.
20. trypsinogen, chymotrypsinogen, carboxypeptidase (for protein), amylase (for carbohydrates), lipase (for lipids)
21. bile salts (for lipids)
22. primarily composed of enterocytes which are columnar absorptive cells with microvilli, with mucous secreting goblet cells throughout, as well as enteroendocrine cells which are at the base of the glands and secrete hormone like substances, and paneth cells which secretes lysozyme to control bacterial flora.
23. well vascularized, type II capillaries, may have a central lacteal for absorption of larger molecules, may have lymph nodules called Peyer's patches.
24. may have a meissner's plexus, which assists in regulating secretion and blood flow.
25. a nerve net in the muscularis layer which helps coordinate peristaltic contractions of muscularis externa.
26. visceral peritoneum.
27. in the submucosa of the duodenum, secretes alkaline-mucoid material and urogastrone.
28. greatest amount of "GALT", Peyer's patches, fewer villi and more goblet cells.
29. simple columnar epithelia with intestinal glands but no villi. abundant goblet cells and lymph rich lamina propria, but no entero-endocrine or paneth cells.
30. epithelial transition from simple columnar to non-keratinized stratified squamous, patchy muscularis mucosa, huge blood vessels in submucosa, skeletal muscle in muscularis externa. transition, patchy, blood, skeletal.
31. parotid secretes mainly serous, submandibular secretes a mixture of mucous and serous, and sublingual secretes mostly mucous.
32. the pancreas' function is mainly to serve as an exocrine gland which secrete digestive enzymes (see question 20), composed of compound acinar glands. it also secretes alkaline bicarbonate in order to neutralize the acidity from gastric digestion.
33. 2% of the pancreas is used for endocrine function, in the form of "islets of langerhans" which are clumped glands which consist of alpha, beta, and delta cells which secrete glucagon, insulin, and somatostatin, respectively.
34. fetal hematopoesis (before shifting to bone marrow), glucagon processing, plasma protein production (such as clotting factors), bile production, and detoxification. blood, glucagon, clotting, bile, detox. detox clotting blood into a bile of glucagon.
35. exocrine because it dumps bile into the intestine, endocrine because it filters blood and adds to it.
36. the vein that brings oxygen poor but potentially nutrient rich blood into the liver from the GI tract.
37. the artery that brings fresh blood to the liver itself.
38. type three discontinuous.
39. basic cell type is the hepatocyte and they are arranged into lobules.
40. hexagonal shaped cell with a large central vein in the middle and a trio of vessels at every other corner of the border of the cell, called the portal area: containing hepatic portal vein (question 36), hepatic artery (question 37), and bile duct.
41. the liver acinus theory of blood flow says that blood flows laterally from the portal areas to the adjacent central vein (creating a diamond shaped functional unit overlayed on top of two lobules). this theory is backed up by the patterns of degradation during liver poisoning.
Sunday, November 23, 2008
histology: male reproductive system
this unit looks at the male reproductive system, focusing on spermiogenesis and the tubular architecture out to the penis. spermiogenesis occurs in the seminiferous tubules of the testis, which are covered on the outside by the tunica vaginalis layer, which is an invagination of the parietal peritoneum, followed by a thick CT tunica albuginea layer which sends CT partitions inwards, dividing the testis into lobes with 1-4 seminiferous tubules each. inside the seminiferous tubules, which are approximately 200um in diameter and 50cm long (but highly convoluted), spermiogenesis begins: type a spermatogonia are the undifferentiated stem cells that reside near the edges of the seminiferous tubules and provide a reserve of potential sperm cells. type b spermatogonia are the cells that have begun differentiating into spermatocytes. spermatocytes begin the process of meoisis, whereby the cell divides into two and halves its chromosomes-- primary spermatocytes are "4N" and secondary spermatocytes are "quasi 2N" that have undergone the first meotic division. spermatids are spermatocytes that have completed meoitic division and are now ready for morphological differentiation. spermatozoans are completed sperm cells that have been morphologically differentiated for swimming and fertilization. thus the order is type a spermatogonia => type b spermatogonia => primary spermatocyte => secondary spermatocyte => spermatid => spermatozoan.
the spermatozoans then swim out of the seminiferous tubules into a series of converging tubules out of the testis into the ductus epididymus, which is a singularly convoluted tubule (50 meters long scrunched up into 50cm) which serves as a maturation and storage site for the spermatozoans, as well as absorbing any excess fluids from spermiogenesis. it then flows upwards through a tube called the ductus deferens, which is straight and has a much thicker muscularis layer (inner longitudinal, middle circular, outer longitudinal) which is responsible for the peristaltic waves during ejaculation. after passing through the prostatic region, the ductus deferens changes into the urethra, which is a common pathway for the urinary and reproductive tract. it is housed in the corpus spongiosum on the dorsal side of the penis, which is one of the three fibroelastic erectile tissues- the other two being two columns of corpus cavernosum on the ventral side. as the urethra goes from the prostatic region to the tip of the penis, it undergoes epithelial transitions from transitional to stratified columnar to stratified squamous.
questions
1. how long does spermatogenesis take to complete and how many sperm are produced per day?
2. where does spermatogenesis take place?
3. what is the testis covered by?
4. describe the rough dimensions of a seminiferous tubule.
5. what are spermatogonia? what are type a and type b spermatogonia?
6. what are spermatocytes? what are primary and secondary spermatocytes?
7. what are spermatids?
8. what are spermatozoans?
9. what are Leydig's cells?
10. what is the ductus epididymis? what is its function?
11. what are the layers of the ductus epididymus?
12. what is the ductus deferens?
13. what are the layers of the ductus deferens?
14. what are the accessory glands?
15. what is erectile tissue?
16. what are the three columns of erectile tissue in the penis?
17. describe the epithelial transitions in the urethra.
answers
1. 75 days, 200,000 sperm produced per day
2. in the stratified cuboidal epithelium of the seminiferous tubules in the testis.
3. tough CT layer called tunica albuginea which sends partitions inwards to form lobules, and a tunica vaginalis on the outside, which is an invagination of the parietal peritoneum.
4. 200um diameter pipe, about 50cm long
5. reserve cells that pool along the back of the seminiferous tubules. type a are stem cells that maintain the stock and type b differentiate into spermatocytes.
6. spermatocytes are spermatogonia that have begun meiotic division, moving towards the lumen of the tubule as they divide. primary spermatocytes are 4N and secondary spermatocytes are quasi-2N cells that have undergone the first meiotic division.
7. spermatids are haploid (2N) cells and are ready to morphologically differentiate.
8. spermatozoans are sperm cells that have completed spermiogenesis and is now specialized morphologically for swimming and fertilization.
9. special endocrine cells within the between the seminiferous tubules that secrete testosterone, promoting spermatogenesis and secondary sex characteristics.
10. the long convoluted duct that leads out of the testis and serves as a maturation / storage site for spermatozoa, and absorbs excess fluids from spermatogenesis.
11. the layers are: PSCC, thin CT lamina propria, muscularis, serosa.
12. the thick, muscular tube leading from the epididymus back to the body which is responsible for the peristaltic waves during ejaculation.
13. PSCC, lamina propria (thin CT, rich in elastic fibers), thick and well developed muscularis (with inner longitudinal, middle circular, outer longitudinal layers), and adventitia.
14. glands that promote sperm survival and transport by adding "seminal fluids", such as the seminal vescicle and prostate.
15. fibroelastic CT mixed with endothelially lined spaces that can accumulate blood.
16. 2 dorsal columns of corpus cavernosum and 1 ventral column of corpus spongiosum.
17. in the prostatic area there is a change from transitional epithelium to stratified columnar, and near tip of the penis another change to stratified squamous.
the spermatozoans then swim out of the seminiferous tubules into a series of converging tubules out of the testis into the ductus epididymus, which is a singularly convoluted tubule (50 meters long scrunched up into 50cm) which serves as a maturation and storage site for the spermatozoans, as well as absorbing any excess fluids from spermiogenesis. it then flows upwards through a tube called the ductus deferens, which is straight and has a much thicker muscularis layer (inner longitudinal, middle circular, outer longitudinal) which is responsible for the peristaltic waves during ejaculation. after passing through the prostatic region, the ductus deferens changes into the urethra, which is a common pathway for the urinary and reproductive tract. it is housed in the corpus spongiosum on the dorsal side of the penis, which is one of the three fibroelastic erectile tissues- the other two being two columns of corpus cavernosum on the ventral side. as the urethra goes from the prostatic region to the tip of the penis, it undergoes epithelial transitions from transitional to stratified columnar to stratified squamous.
questions
1. how long does spermatogenesis take to complete and how many sperm are produced per day?
2. where does spermatogenesis take place?
3. what is the testis covered by?
4. describe the rough dimensions of a seminiferous tubule.
5. what are spermatogonia? what are type a and type b spermatogonia?
6. what are spermatocytes? what are primary and secondary spermatocytes?
7. what are spermatids?
8. what are spermatozoans?
9. what are Leydig's cells?
10. what is the ductus epididymis? what is its function?
11. what are the layers of the ductus epididymus?
12. what is the ductus deferens?
13. what are the layers of the ductus deferens?
14. what are the accessory glands?
15. what is erectile tissue?
16. what are the three columns of erectile tissue in the penis?
17. describe the epithelial transitions in the urethra.
answers
1. 75 days, 200,000 sperm produced per day
2. in the stratified cuboidal epithelium of the seminiferous tubules in the testis.
3. tough CT layer called tunica albuginea which sends partitions inwards to form lobules, and a tunica vaginalis on the outside, which is an invagination of the parietal peritoneum.
4. 200um diameter pipe, about 50cm long
5. reserve cells that pool along the back of the seminiferous tubules. type a are stem cells that maintain the stock and type b differentiate into spermatocytes.
6. spermatocytes are spermatogonia that have begun meiotic division, moving towards the lumen of the tubule as they divide. primary spermatocytes are 4N and secondary spermatocytes are quasi-2N cells that have undergone the first meiotic division.
7. spermatids are haploid (2N) cells and are ready to morphologically differentiate.
8. spermatozoans are sperm cells that have completed spermiogenesis and is now specialized morphologically for swimming and fertilization.
9. special endocrine cells within the between the seminiferous tubules that secrete testosterone, promoting spermatogenesis and secondary sex characteristics.
10. the long convoluted duct that leads out of the testis and serves as a maturation / storage site for spermatozoa, and absorbs excess fluids from spermatogenesis.
11. the layers are: PSCC, thin CT lamina propria, muscularis, serosa.
12. the thick, muscular tube leading from the epididymus back to the body which is responsible for the peristaltic waves during ejaculation.
13. PSCC, lamina propria (thin CT, rich in elastic fibers), thick and well developed muscularis (with inner longitudinal, middle circular, outer longitudinal layers), and adventitia.
14. glands that promote sperm survival and transport by adding "seminal fluids", such as the seminal vescicle and prostate.
15. fibroelastic CT mixed with endothelially lined spaces that can accumulate blood.
16. 2 dorsal columns of corpus cavernosum and 1 ventral column of corpus spongiosum.
17. in the prostatic area there is a change from transitional epithelium to stratified columnar, and near tip of the penis another change to stratified squamous.
Wednesday, November 19, 2008
histology: female reproductive system
this section covered the basic anatomy of the female reproductive system and follows the life of a oocyte from its creation until implantation in the uterus. the ovaries start with ~400,000 oocytes at puberty, out of which 400 are ovulated. the process begins in the ovaries, which are masses of mainly connective tissue, surrounded by a simple cuboidal germinal epithelium and tunica albuginea connective tissue layer. inside the ovaries are many "follicles" at varying stages of development. each follicle begins as a primordial follicle, which is an oocyte (~30um) surrounded by simple cuboidal follicular cells. the next stage is a primary follicle, where a slightly larger oocyte (50um) is surrounded by a cuboidal follicular layer that begins to stratify, and a light pink zona pelucida appears around the oocyte. the next stage is a secondary follicle, with a larger oocyte (~100um), the beginning of the development of an "antrum", which is a space in the follicle that is filled with follicular liquor, and the emergence of the theca, which is a double layered perimeter in the follicular layer that has two parts: the theca interna, which secretes estrogen, and the theca extra, which is made up of connective tissue and smooth muscle. the next and final phase is the tertiary, or graafian, or mature follicle, in which the larger oocyte is surrounded by a nest of follicular cells, the antrum makes up the bulk of the follicle and nearly pinches off the oocyte, and the entire follicular diameter approaches 10-12 mm.
at this point the tertiary follicle releases its oocyte from the ovaries (the released oocyte is now an ovum) and the ovum begins to travel down the oviduct. the oviduct contains many epithelial folds of ciliated simple columnar mucosa, with a muscularis composed of an inner circular layer and outer longitudinal layer, and an outer serosa layer. around the 2nd day after the release of the ovum, it can be fertilized in the upper 1/3 of the oviduct, called the ampula. it then travels down to the uterus for implantation, which generally occurs ~7 days later. the uterus has three layers: endometrium, myometrium, and perimetrium. the myometrium is made of smooth muscle and perimetrium is the serosa; neither of these layers change much during the menstrual cycle. contrast this with the endometrium, which undergoes dramatic growth and breakdown during the menstrual cycle, beginning with the menstrual phase, then the follicular / proliferative phase, then the progestational or secretory phase, then the gravis phase. the endometrium is broken down into two functional layers: the stratum basale, which stays the same during the cycle, and the stratum functionale, which is the layer that builds up and degenerates. while the follicle is developing in the ovaries the endometrium is building up a highly vascularized tissue in preparation for implantation. if implantation does not occur, then the stratum functionale breaks down during the "menstrual phase".
below the uterus is the cervix, which is the opening to the vagina. the transition from the cervix to the vagina happens dramatically, changing swiftly from the simple columnar epithelium in the cervix to the stratified squamous of the vagina. the vagina has 3 layers, the top layer being mostly parakeratinized stratified squamous, with a chaotically organized muscularis underneath, and an adventitia layer beyond.
one other note: the corpeus luteum is the remnant of the tertiary follicle after the ovum is released from the ovaries. if pregnancy does occur, the corpeus luteum continues to enlarge in the ovaries and secrete estrogen (which helps the development and growth of sex organs) and progesterone (which prepares the uterus for pregnancy and the mammary glands for lactation) for ~10 weeks or until the placenta takes over. if pregnancy does not occur, then the corpeus luteum breaks down in 12-14 days and forms a whitish mass called the corpeus albicans.
questions
1. how does oogenesis affect production of hormones?
2. describe the physical makeup of the ovary.
3. how many oocytes do the ovaries start with at puberty and about how many are ovulated in total?
4. describe the primordial follicle.
5. what is the development of the primordial follicle mediated by?
6. what are atretic follicles?
7. describe the primary follicle.
8. describe the secondary follicle.
9. what is follicular liquor and what does it develop into?
10. what is theca and what are the two layers?
11. describe the tertiary follicle.
12. what is the corpeus luteum and what does it do?
13. what is the name for the structure that the corpeus luteum degenerates into?
14. what are the physical characteristics of the oviduct?
15. what are the three layers of the uterus?
16. what are the physical characteristics of the endometrium?
17. what are the phases of the menstrual cycle?
18. describe the timing of fertilization and implantation after the ovum is released from the ovaries.
19. what is histologically unique about the transition from the cervix to the vagina?
20. what are the layers of the vagina?
answers
1. oogenesis produces estrogen to promote growth and development of sex organs, progesterone to prepare uterus for pregnancy and mammary glands for lactation.
2. mostly connective tissue with follicles in varying stages of development. covered by germinal epithelium (simple cuboidal) and the tunica albuginea (CT) layer.
3. 400,000 and 400
4. an oocyte enclosed in a squamous layer of follicular cells, about 30um
5. FSH (follicle stimulating hormone)
6. follicles in the ovaries that have degenerated
7. a larger oocyte (50um) surrounded by cuboidal follicular cells, with a pink zona pellucida developing around the oocyte.
8. an even larger oocyte (100um) surrounded by stratified cuboidal follicular cells, up to 1-2mm total diameter
9. the secretions from follicular cells in a secondary follicle that develop into an antrum.
10. theca is a double layered perimeter that appears in the secondary follicle. the theca interna has estrogen secreting cells and the theca externa is CT and smooth muscle.
11. the tertiary, or mature, or graafian follicle is up to 10mm in total diameter with a huge antrum and the oocyte surrounded by a nest of follicular cells.
12. the corpeus luteum is a temporary structure that is formed from the remains of the tertiary follicle which rapidly proliferates to secrete progesterone and estrogen. if pregnancy occurs, the corpeus luteum continues to enlarge and secretes estrogen and progesterone until the placenta takes over. if pregnancy does not occur, then the corpeus luteum degenerates in 12-14 days.
13. corpus albicans
14. has a mucosa, muscularis, and serosa layers. mucosa has many folds with simple columnar epithelium, with cilia, some secretory cells (to provide nutrients for ova) and lamina propria. muscularis has inner circular and outer longitudinal smooth muscle.
15. endometrium, myometrium (muscularis), perimetrium (serosa).
16. simple columnar epithelium, simple tubular uterine glands, stratum basalis/stratumfunctionalis.
17. the menstrual phase, the follicular or proliferative phase, the progestational or secretory phase, and the gravid phase.
18. fertilization occurs in the ampula (upper 1/3) of the oviduct ~2 days after the ovum is released from the ovaries, and implantation generally happens ~7 days later.
19. the transition from the cervix to the vagina occurs dramatically, changing from simple columnar to stratified squamous epithelium within a single layer of cells.
20. stratified squamous epithelium (mostly parakeratinized), lamina propria with elastic fibers, muscularis (poorly organized), adventitia.
at this point the tertiary follicle releases its oocyte from the ovaries (the released oocyte is now an ovum) and the ovum begins to travel down the oviduct. the oviduct contains many epithelial folds of ciliated simple columnar mucosa, with a muscularis composed of an inner circular layer and outer longitudinal layer, and an outer serosa layer. around the 2nd day after the release of the ovum, it can be fertilized in the upper 1/3 of the oviduct, called the ampula. it then travels down to the uterus for implantation, which generally occurs ~7 days later. the uterus has three layers: endometrium, myometrium, and perimetrium. the myometrium is made of smooth muscle and perimetrium is the serosa; neither of these layers change much during the menstrual cycle. contrast this with the endometrium, which undergoes dramatic growth and breakdown during the menstrual cycle, beginning with the menstrual phase, then the follicular / proliferative phase, then the progestational or secretory phase, then the gravis phase. the endometrium is broken down into two functional layers: the stratum basale, which stays the same during the cycle, and the stratum functionale, which is the layer that builds up and degenerates. while the follicle is developing in the ovaries the endometrium is building up a highly vascularized tissue in preparation for implantation. if implantation does not occur, then the stratum functionale breaks down during the "menstrual phase".
below the uterus is the cervix, which is the opening to the vagina. the transition from the cervix to the vagina happens dramatically, changing swiftly from the simple columnar epithelium in the cervix to the stratified squamous of the vagina. the vagina has 3 layers, the top layer being mostly parakeratinized stratified squamous, with a chaotically organized muscularis underneath, and an adventitia layer beyond.
one other note: the corpeus luteum is the remnant of the tertiary follicle after the ovum is released from the ovaries. if pregnancy does occur, the corpeus luteum continues to enlarge in the ovaries and secrete estrogen (which helps the development and growth of sex organs) and progesterone (which prepares the uterus for pregnancy and the mammary glands for lactation) for ~10 weeks or until the placenta takes over. if pregnancy does not occur, then the corpeus luteum breaks down in 12-14 days and forms a whitish mass called the corpeus albicans.
questions
1. how does oogenesis affect production of hormones?
2. describe the physical makeup of the ovary.
3. how many oocytes do the ovaries start with at puberty and about how many are ovulated in total?
4. describe the primordial follicle.
5. what is the development of the primordial follicle mediated by?
6. what are atretic follicles?
7. describe the primary follicle.
8. describe the secondary follicle.
9. what is follicular liquor and what does it develop into?
10. what is theca and what are the two layers?
11. describe the tertiary follicle.
12. what is the corpeus luteum and what does it do?
13. what is the name for the structure that the corpeus luteum degenerates into?
14. what are the physical characteristics of the oviduct?
15. what are the three layers of the uterus?
16. what are the physical characteristics of the endometrium?
17. what are the phases of the menstrual cycle?
18. describe the timing of fertilization and implantation after the ovum is released from the ovaries.
19. what is histologically unique about the transition from the cervix to the vagina?
20. what are the layers of the vagina?
answers
1. oogenesis produces estrogen to promote growth and development of sex organs, progesterone to prepare uterus for pregnancy and mammary glands for lactation.
2. mostly connective tissue with follicles in varying stages of development. covered by germinal epithelium (simple cuboidal) and the tunica albuginea (CT) layer.
3. 400,000 and 400
4. an oocyte enclosed in a squamous layer of follicular cells, about 30um
5. FSH (follicle stimulating hormone)
6. follicles in the ovaries that have degenerated
7. a larger oocyte (50um) surrounded by cuboidal follicular cells, with a pink zona pellucida developing around the oocyte.
8. an even larger oocyte (100um) surrounded by stratified cuboidal follicular cells, up to 1-2mm total diameter
9. the secretions from follicular cells in a secondary follicle that develop into an antrum.
10. theca is a double layered perimeter that appears in the secondary follicle. the theca interna has estrogen secreting cells and the theca externa is CT and smooth muscle.
11. the tertiary, or mature, or graafian follicle is up to 10mm in total diameter with a huge antrum and the oocyte surrounded by a nest of follicular cells.
12. the corpeus luteum is a temporary structure that is formed from the remains of the tertiary follicle which rapidly proliferates to secrete progesterone and estrogen. if pregnancy occurs, the corpeus luteum continues to enlarge and secretes estrogen and progesterone until the placenta takes over. if pregnancy does not occur, then the corpeus luteum degenerates in 12-14 days.
13. corpus albicans
14. has a mucosa, muscularis, and serosa layers. mucosa has many folds with simple columnar epithelium, with cilia, some secretory cells (to provide nutrients for ova) and lamina propria. muscularis has inner circular and outer longitudinal smooth muscle.
15. endometrium, myometrium (muscularis), perimetrium (serosa).
16. simple columnar epithelium, simple tubular uterine glands, stratum basalis/stratumfunctionalis.
17. the menstrual phase, the follicular or proliferative phase, the progestational or secretory phase, and the gravid phase.
18. fertilization occurs in the ampula (upper 1/3) of the oviduct ~2 days after the ovum is released from the ovaries, and implantation generally happens ~7 days later.
19. the transition from the cervix to the vagina occurs dramatically, changing from simple columnar to stratified squamous epithelium within a single layer of cells.
20. stratified squamous epithelium (mostly parakeratinized), lamina propria with elastic fibers, muscularis (poorly organized), adventitia.
Tuesday, November 18, 2008
histology sample test
courtesy of a bunch of hard working ncnmers:
SAMPLE HISTOLOGY TEST
QUESTION: The pancreas is....
A. An exocrine gland
B. Mostly exocrine with 2% endocrine
C. Mostly endocrine with 2% exocrine
ANSWER: B. Mostly exocrine with 2% endocrine
QUESTION: Which theory that most accurately describes the function of the liver?
A. Liver acinus
B. Classical lobule
C. Non-classical lobule
ANSWER: A. Liver acinus
QUESTION: Which salivary gland secretes only serous fluid?
A. Parotid
B. Sublingual
C. Submandibular
D. Both A & C
ANSWER: A. Parotid
QUESTION: Saliva is a mix of water and what?
A. Serous fluid
B. Mucous
C. Amylase
D. Antibodies
E. all the above
ANSWER: E. all the above
QUESTION: Where are compound acinar glands found?
A. Liver
B. Salivary
C. Pancreas
D. both A & B
E. both C & B
ANSWER: E. both C & B
QUESTION: The _______ can be thicker in some places, such as sphincters
ANSWER: muscularis
QUESTION: Which of the following comprise the mucosa?
A. Muscularis mucosa
B. Epithelium
C. Mesothelium
D. Lamina propria
E. Meissener’s plexus
ANSWER: A, B and D
QUESTION: Which has a stratified squamous epithelium:
A. Duodenum
B. Stomach
C. Esophagus
ANSWER: C. esophagus
QUESTION: Which of the following have entero-endocrine cells?
A. Esophagus
B. Jejunum
C. Large intestine
D. Stomach
ANSWER: B & D
QUESTION: What is unique about the stomach?
A. The muscularis externa has three layers
B. It has a lot of goblet cells
C. Greatest amount of GALT
D. It has Brunner’s glands
ANSWER: A. The muscularis externa has three layers
QUESTION: True or False...Alpha, Beta and Delta cells are part of the endocrine glands of the pancreas.
ANSWER: True
QUESTION: Trends down the entire intestines include:
A. Increasing surface area
B. Decreasing surface area
C. Decreasing goblet cells
D. Decreasing lymphatic tissue
ANSWER: B. Decreasing surface area
QUESTION: Which gland secretes alkaline-mucoid material and urogastrone?
A. Gastric gland
B. Esophageal gland
C. Parotid gland
D. Duodenal gland
ANSWER: D. Duodenal gland
QUESTION: Which part of the renal tubular system does most of the reabsorption?
ANSWER: Proximal tubule (extensively convoluted, apical mirovilli, simple cubodial)
QUESTION: What three tubes constitute the portal area?
ANSWER: Hepatic portal vein, hepatic artery, bile duct
QUESTION: What is the correct order of “Flow of Blood to the Liver”?
A. large intestine, liver, portal vein, venous system, heart
B. stomach & small intestine, liver, venous system, portal vein, heart
C. stomach & small intestine, portal system, liver, venous system, heart
D. stomach & small intestine, liver, portal system, venous system, heart
ANSWER: D
QUESTION: The following are well vascularized, except...
A. Tunica intima
B. Tunica adventitia
C. Submucosa of digestive system
D. Lamina propria of the small intestine
ANSWER: A. Tunica intima
QUESTION: Multiple True or False...
• Epiglottis is a conducting tissue, or evidence of conduction tissue
• Cilia is a conducting tissue, or evidence of conducting tissue
• Simple cubodial epithelium is a conducting tissue, or evidence of conducting tissue
• Goblet cells are a conducting tissue, or evidence of conduction tissue
ANSWER: True = epiglottis, cilia and goblet cells; False = simple cubodial epithelium
QUESTION: What are the two kinds of lymphatic tissue and how are they different from each other?
ANSWER: Diffused lymphatic tissue is a scattering of lymphocytes. Nodules are semi-discrete masses of lymphocytes.
QUESTION: What are the four kinds of lymphatic organs and their main function?
ANSWER: 1. Lymph nodes are inline filters of lymph 2. Spleen is the largest lymph organ and an in-line filter of the blood 3. Thymus is a T-lymphocyte manufacturing center. 4. Tonsils are masses of lymphoid tissue that filter lymph in the oral cavity
QUESTION: Which of the following are listed from largest to smallest?
A. Arteriole – artery – vein – capillary
B. Artery – arteriole – sinusoidal capillary – capillary
C. Areriole – vein – venule – artery
D. Artery – vein – capillary – sinusoidal capillary
ANSWER: B. Artery – arteriole – sinusoidal capillary – capillary
QUESTION: Where in the kidneys is urine first seen?
ANSWER: Area cribrosa
QUESTION: What type of gland is responsible for hormone secretion?
ANSWER: Endocrine
QUESTION: Where in the kidneys are the pyramids?
ANSWER: In the medulla
QUESTION: Where do you find the arcuate vein and artery?
ANSWER: Between medulla and cortex
QUESTION: Where is the serosa rather than adventitia present in the male reproductive system?
A. Ductus deferens
B. Urethra
C. Ductus epididymis
D. Penis
ANSWER: C. Ductus epididymis
QUESTION: What cells secrete testosterone?
A. Interstitial leydig cells
B. Sertoli cells
C. Spermatids
D. Sperms cells
ANSWER: A. Interstitial leydig cells
QUESTION: __________ is a hormone produced in the kidneys that causes the bone marrow to produce red blood cells.
ANSWER: Erythropoietin
QUESTION: Where in the body do you find type II capillaries?
ANSWER: in the glomerulus/Bowman’s capusule
SAMPLE HISTOLOGY TEST
QUESTION: The pancreas is....
A. An exocrine gland
B. Mostly exocrine with 2% endocrine
C. Mostly endocrine with 2% exocrine
ANSWER: B. Mostly exocrine with 2% endocrine
QUESTION: Which theory that most accurately describes the function of the liver?
A. Liver acinus
B. Classical lobule
C. Non-classical lobule
ANSWER: A. Liver acinus
QUESTION: Which salivary gland secretes only serous fluid?
A. Parotid
B. Sublingual
C. Submandibular
D. Both A & C
ANSWER: A. Parotid
QUESTION: Saliva is a mix of water and what?
A. Serous fluid
B. Mucous
C. Amylase
D. Antibodies
E. all the above
ANSWER: E. all the above
QUESTION: Where are compound acinar glands found?
A. Liver
B. Salivary
C. Pancreas
D. both A & B
E. both C & B
ANSWER: E. both C & B
QUESTION: The _______ can be thicker in some places, such as sphincters
ANSWER: muscularis
QUESTION: Which of the following comprise the mucosa?
A. Muscularis mucosa
B. Epithelium
C. Mesothelium
D. Lamina propria
E. Meissener’s plexus
ANSWER: A, B and D
QUESTION: Which has a stratified squamous epithelium:
A. Duodenum
B. Stomach
C. Esophagus
ANSWER: C. esophagus
QUESTION: Which of the following have entero-endocrine cells?
A. Esophagus
B. Jejunum
C. Large intestine
D. Stomach
ANSWER: B & D
QUESTION: What is unique about the stomach?
A. The muscularis externa has three layers
B. It has a lot of goblet cells
C. Greatest amount of GALT
D. It has Brunner’s glands
ANSWER: A. The muscularis externa has three layers
QUESTION: True or False...Alpha, Beta and Delta cells are part of the endocrine glands of the pancreas.
ANSWER: True
QUESTION: Trends down the entire intestines include:
A. Increasing surface area
B. Decreasing surface area
C. Decreasing goblet cells
D. Decreasing lymphatic tissue
ANSWER: B. Decreasing surface area
QUESTION: Which gland secretes alkaline-mucoid material and urogastrone?
A. Gastric gland
B. Esophageal gland
C. Parotid gland
D. Duodenal gland
ANSWER: D. Duodenal gland
QUESTION: Which part of the renal tubular system does most of the reabsorption?
ANSWER: Proximal tubule (extensively convoluted, apical mirovilli, simple cubodial)
QUESTION: What three tubes constitute the portal area?
ANSWER: Hepatic portal vein, hepatic artery, bile duct
QUESTION: What is the correct order of “Flow of Blood to the Liver”?
A. large intestine, liver, portal vein, venous system, heart
B. stomach & small intestine, liver, venous system, portal vein, heart
C. stomach & small intestine, portal system, liver, venous system, heart
D. stomach & small intestine, liver, portal system, venous system, heart
ANSWER: D
QUESTION: The following are well vascularized, except...
A. Tunica intima
B. Tunica adventitia
C. Submucosa of digestive system
D. Lamina propria of the small intestine
ANSWER: A. Tunica intima
QUESTION: Multiple True or False...
• Epiglottis is a conducting tissue, or evidence of conduction tissue
• Cilia is a conducting tissue, or evidence of conducting tissue
• Simple cubodial epithelium is a conducting tissue, or evidence of conducting tissue
• Goblet cells are a conducting tissue, or evidence of conduction tissue
ANSWER: True = epiglottis, cilia and goblet cells; False = simple cubodial epithelium
QUESTION: What are the two kinds of lymphatic tissue and how are they different from each other?
ANSWER: Diffused lymphatic tissue is a scattering of lymphocytes. Nodules are semi-discrete masses of lymphocytes.
QUESTION: What are the four kinds of lymphatic organs and their main function?
ANSWER: 1. Lymph nodes are inline filters of lymph 2. Spleen is the largest lymph organ and an in-line filter of the blood 3. Thymus is a T-lymphocyte manufacturing center. 4. Tonsils are masses of lymphoid tissue that filter lymph in the oral cavity
QUESTION: Which of the following are listed from largest to smallest?
A. Arteriole – artery – vein – capillary
B. Artery – arteriole – sinusoidal capillary – capillary
C. Areriole – vein – venule – artery
D. Artery – vein – capillary – sinusoidal capillary
ANSWER: B. Artery – arteriole – sinusoidal capillary – capillary
QUESTION: Where in the kidneys is urine first seen?
ANSWER: Area cribrosa
QUESTION: What type of gland is responsible for hormone secretion?
ANSWER: Endocrine
QUESTION: Where in the kidneys are the pyramids?
ANSWER: In the medulla
QUESTION: Where do you find the arcuate vein and artery?
ANSWER: Between medulla and cortex
QUESTION: Where is the serosa rather than adventitia present in the male reproductive system?
A. Ductus deferens
B. Urethra
C. Ductus epididymis
D. Penis
ANSWER: C. Ductus epididymis
QUESTION: What cells secrete testosterone?
A. Interstitial leydig cells
B. Sertoli cells
C. Spermatids
D. Sperms cells
ANSWER: A. Interstitial leydig cells
QUESTION: __________ is a hormone produced in the kidneys that causes the bone marrow to produce red blood cells.
ANSWER: Erythropoietin
QUESTION: Where in the body do you find type II capillaries?
ANSWER: in the glomerulus/Bowman’s capusule
Monday, November 17, 2008
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