this lecture is a continuation of the esophageal disorder lecture, the second in the GI series by Dr. Thom. we finished up the obstructive esophageal disorders: extrinsic compression, esophageal cancers, barrett esophagus, schatzki ring, plummer vinson, inflammation, candida. extrinsic compression of the esophagus causes dysphagia and results from a number of sources such as abnormal subclavian artery, diverticulosis, mediastinal masses, enlarged heart, cervical spurs. cancer of the esophagus is divided into two main categories: 75% of cases are squamous cell carcinoma, which affects the non keratinizing stratified squamous epithelium and is from tobacco, alcohol, and other carcinogens. adenocarcinoma results from metaplasia of stratified squamous cells, which then turn into barrett's epithelium, which can then undergo more dysplasia and turn into adenocarcinoma. adenocarcinoma does not have a clear link to alcoholism but is connected with smoking, scleroderma/other motor disorders, obesity, drugs, diet. schatzki rings and plummer vinson both involve an extra esophageal growth of some sort; schatzki rings are lower esophageal rings that cause intermittent dysphagias while plummer vinson is an esophageal web, accompanied by fe deficiency anemia.
GERD is gastric reflux caused by relaxation of the LES for various reasons. normally the regurgitation of gastric contents is protected by the LES constriction, downward peristaltic motion, and alkaline saliva mixing. the LES tone can be decreased by a number of factors such as drugs, hormones, certain foods, and GERD symptoms can be worsened with smoking, obesity, and pregnancy. a patient with GERD often experiences heartburn symptoms in addition to possible respiratory complaints due to aspiration of gastric contents, dysphagia / odynophagia, and waterbrash, which is copious salivary secretions in response to GERD. diagnosis is made by endoscopy with biopsy, esophagram with barium swallow, EGD to detect esophagitis (associated in 50% of cases), barrett's esophagus, and to rule out peptic ulcer disease.
the last two esophageal disorders are related to bleeding: mallory weiss is upper GI bleeding caused by lacerations at the gastroesophageal junction and can result in hematemesis, vomiting, or in more severe cases, blood in the stool. it has been shown to be correlated to high consumption of alcohol and aspirin. esophageal varices are varicose veins in the esophagus caused by increased portal hypertension (hep B, C, cirrhosis, alcoholism, fatty liver can all cause), which might rupture and cause massive bleeding in the stomach and out of the mouth.
questions
obstructive esophageal disorders, cont'd...
1. what is esophageal extrinsic compression due to? †
2. what percentage of esophageal cancers are due to SCC vs. adenocarcinoma? √
3. what is the etiology of SCC of the esophagus and what tissue layer does it affect? †
4. what is the treatment of SCC in the esophagus? √
5. what part of the esophagus is adenocarcinoma likely to affect? √
6. describe the pathogenesis of adenocarcinoma of the esophagus. †√
7. what is barrett epithelium? √
8. patients with barrett esophagus are more likely to have... √
9. what are the risk factors for esophageal adenocarcinoma? XX
10. what is a schatzki ring? †√
11. how common is a schatzki ring and what is the prognosis? †√
12. what is plummer vinson syndrome? X√
13. what is the etiology of plummer vinson syndrome? √
14. plummer vinson is resolved by treatment of... √
15. what are some factors that cause inflammation of the esophagus? X√
16. ∂escribe the clinical picture of a patient that has esophageal inflammation due to candida. X†
17. describe the imaging findings of the above patient. X
GERD...
18. what is GERD? √
19. reflux of acid into the esophagus is normally protected by... √
20. what are the causes of GERD? †
21. what can decreased LES pressure be caused by? X
22. what are some typical symptoms of a patient with GERD?
23. what are some extra-esphageal symptoms of a patient with GERD? X
24. patients with GERD are often misdiagnosed with... √
25. what are the imaging techniques used to diagnose GERD? †
26. what is the EGD technique useful for in the diagnosis of GERD? √
27. what are the complications of GERD? X
28. what are the treatments for GERD? X
bleeding problems...
29. what is mallory weiss syndrome?
30. what are the symptoms of mallory weiss?
31. what are the less common symptoms of mallory weiss?
32. what are two substances that have been linked to mallory weiss?
33. what are esophageal varices due to?
34. esophageal varices might lead to...
answers
1. mediastinal masses, aberrant right subclavian artery, enlarged heart, cervical spurs, divertuculi.
2. 2/3 SCC 1/3 adenocarcinoma.
3. tobacco, alcohol, other carcinogens, affects non keratinizing stratified squamous cell epithelium.
4. if surgery, involves removing most of the neck because of the high lymph node concentration.
5. mid and distal esophagus.
6. gastric reflux causes metaplasia of normal stratified squamous cells, turning them into "barrett epithelium", then dysplasia, then adenocarcinoma.
7. specialized intestinal epithelial layer containing goblet cells.
8. lower LES pressure and worse esophageal peristalsis, therefore more acid reflux.
9. not alcohol (!), smoking, scleroderma/other motor disorders, obesity, drugs, diet.
10. a lower esophageal ring that causes intermittent dysphagias.
11. 6-14% of patients who undergo GI exams; usually asymptomatic.
12. dysphagia for solids, esophageal webs (thin mucosal membrane that grows across lumen), fe deficiency anemia.
13. excess smoking and drinking.
14. anemia.
15. chronic debilitating disease, steroids, antibiotics, immunosuppresants, chemo, estrogen. [chronic drugs drugs drugs rays boobs]
16. dysphagia with intense pain of short duration, often tolerate only liquids, oral thrush.
17. barium swallow would show shaggy mucosa or filling defects, endoscopy would show white mucosa and swelling.
18. gastric esophageal reflux disease, a common condition characterized by heartburn and acid regurgitation symptoms.
19. LES, downward peristaltic motion, alkaline saliva.
20. decrease of LES pressure, smoking, pregnancy, obesity.
21. drugs (morphine, diazepam, calcium channel blocker, nitrates, beta-blockers), hormones (secretin, cholecystokinin, glucagon), foods (alcohol, caffeine, lipids, chocolate).
22. heartburn felt usually after eating or bending over, respiratory complications from regurgitation, dysphagia, odynophagia, waterbrash. [heartburn, breathe, swallow, swallow, water]
23. coughing/wheezing, aspiration pneumonia, fatigue, chest pain. [cough, pneumonia, tired, pain]
24. asthma because of the cough which is caused by aspiration.
25. endoscopy with biopsy, barium esophagram, esophagogastroduodenoscopy.
26. identifying esophagitis, barrett esophagus, ruling out peptic ulcer.
27. esophagitis (50% of cases), barrett's esophagus, stricture of distal esophagus, respiratory complications.
28. improve diet, cut out alcohol, stay elevated, heel drops, avoid constricting clothing. [diet, elevation, dropping, clothing]
29. gastroesophageal junction lacerations and upper GI bleeding.
30. hematemesis, followed by wretching / vomiting.
31. hematochezia, melena, syncope, abdominal pain.
32. exceess alcohol and aspirin.
33. anything that increases portal hypertension: Hep B, Hep C, cirrhosis, alcoholism, fatty liver.
34. rupture, massive bleeding into the stomach and out of the mouth (a life threatening emergency).
Showing posts with label esophagus. Show all posts
Showing posts with label esophagus. Show all posts
Monday, February 1, 2010
Sunday, February 22, 2009
organ systems: GI physiology lecture 1
this is the first lecture in the series of GI physiology by Dr. Steven Sandburg Lewis. we covered a few introductory concepts: basal electric rhythms, some basic anatomy of the mouth and esophagus, gastric motility, and vomiting.
basal electrical rhythms are slow depolarizations that are initiated in GI tissue by the interstitial cells between the two layers of the muscularis mucosa. they generally occur on the frequency of 3-12 per minute, and if they reach the threshold frequency, an action potential will be induced and contraction of the muscle will occur. distention of the lumen in the GI tract, as well as parasympathetic and hormonal stimulation can depolarize the basal rhythm, bringing it closer to the threshold potential and therefore increasing the AP frequency. sympathetic activity and norepinephrine can have the opposite effect, hyperpolarizing the BER and lowering AP frequency.
the act of swallowing is an event in the pharanx is very much a coordinated event: the uvula is tissue in the back of the pharynx that prevents food (the bolus) from entering the nasal canal. the epiglottis is a flap of tissue that opens the esophagus and closes off the trachea. the bolus must pass through the upper esophageal sphincter (UES) which is normally closed to prevent air from entering the stomach. the bolus is then transported down by peristaltic motion to the lower esophageal sphincter (LES), which is normally closed to prevent gastric reflux.
three types of peristalsis are described: primary peristalsis occurs as a direct reaction to swallowing food. secondary peristalsis occurs even without swallowing- it is initiated when there is already a bolus stuck in the esophagus. tertiary peristalsis occurs in response to stress or loud noise, and contracts the entire length of the esophagus simultaneously- which in effect prevents peristalsis.
when the bolus passes through the LES and into the stomach, it induces "receptive relaxation" and peristalsis in the stomach muscularis layers as well. the stomach generally mixes on the frequency of 3 "constrictor waves" per minute, and includes an action called "retropulsion"- a backwards movement of the gastric contents to aid in mixing. (note: the fundus and body of the stomach can accomodate up to 1.5 L of food)
the last topic in this lecture was vomiting. there are three stages to vomiting: nausea, retching, and vomiting. nausea can be induced by a variety of events such as distention of organs, altered body chemistry, extreme fear or stress, etc. in the GI tract, this is manifested as antiperistaltic motion in the jejunum, relaxing of gastric muscle tone, and eventual reflux of duodenal contents into the stomach. in the next phase, wretching, the stomach contracts and pushes upwards into the thorax, against the closed LES. finally, vomiting occurs when the food gets ejected through the UES.
questions
BER's..
1. what are BER's? what are they generated by?
2. how is an action potential produced from a BER?
3. how is the maximum rate of muscle contraction set?
4. how does depolarization relate to action potential production? what causes depolarization of BER?
5. how does hyperpolarization relate to action potential production? what causes hyperpolarization of BER?
the mouth and esophagus...
6. dysphagia is...
7. what does the uvula do?
8. what does the UES do?
9. what does the LES do?
10. what is the difference between the three types of peristalsis in the esophagus?
11. when is tertiary peristalsis painful?
12. what is the relaxation of LES mediated by?
13. what foods relax LES tone?
gastric motility and emptying...
14. what is the first response of the stomach to the entering bolus?
15. fundus and body can accommodate up to...
16. what is the frequency of gastric mixing?
17. how does stress affect gastric contraction?
18. what is retropulsion?
19. how does fat content relate to gastric contraction
20. how many episodes of gastric reflux does the average person have per meal?
vomiting...
21. three phases of vomiting...
22. what occurs during nausea?
23. what occurs during retching?
24. what might happen due to excessive wretching?
25. what occurs during vomiting?
26. what is the vomiting center in the brain affected by?
27. what is an emetic? what are some examples?
answers
1. basal electrical rhythm, generated by interstitial cells between the circular and longitudinal muscularis mucosa.
2. when the BER reaches the threshold potential, an action potential is initiated.
3. by the slow wave frequency.
4. increases the AP frequency, cased by distention of lumen, parasympathetic and hormonal stimulation.
5. decreases AP frequency, caused by sympathetic activity, NE
6. difficulty swallowing.
7. prevents efflux of food into the nasal pharynx.
8. prevents air from getting into the stomach.
9. prevents gastric secretions from entering esophagus.
10. primary is in response to swallowing food. secondary is peristalsis without swallowing- when something is stuck in the esophagus. tertiary has no known function- can be stimulated by loud noises or stress and contracts the whole esophagus.
11. it can cause chest pain in individuals with esophageal motility problems.
12. vagus nerve, VIP, nitric oxide
13. alcohol, antacids, proton pump inhibitors, mint, chocolate, viagra (by way of NO), opiates, drugs to treat angina, bronchodilators. progesterone.
14. "receptive relaxation"
15. 1.5 L
16. 3 constrictor waves / minute.
17. it can cause contraction of the entire stomach (similar to tertiary esophageal contraction) which blanches blood to the brain/muscles and eventually can cause ulcers.
18. the backward motion of contents (to aid in mixing)
19. causes the gastric contents to mix longer. fats float on top and are emptied last.
20. about 3.
21. nausea, retching, vomiting.
22. relaxing of gastric tone, antiperistalsis begins in the jejunum, and eventual reflux of duodenal contents into stomach.
23. upward contraction of stomach, with LES closed.
24. a hiatal hernia.
25. food gets ejected through UES.
26. distention or irritation of viscera, cerebral events, or altered body chemistry. could be stimulated from GI or kidneys.
27. a substance which induces vomiting, such as ipecacuanha.
basal electrical rhythms are slow depolarizations that are initiated in GI tissue by the interstitial cells between the two layers of the muscularis mucosa. they generally occur on the frequency of 3-12 per minute, and if they reach the threshold frequency, an action potential will be induced and contraction of the muscle will occur. distention of the lumen in the GI tract, as well as parasympathetic and hormonal stimulation can depolarize the basal rhythm, bringing it closer to the threshold potential and therefore increasing the AP frequency. sympathetic activity and norepinephrine can have the opposite effect, hyperpolarizing the BER and lowering AP frequency.
the act of swallowing is an event in the pharanx is very much a coordinated event: the uvula is tissue in the back of the pharynx that prevents food (the bolus) from entering the nasal canal. the epiglottis is a flap of tissue that opens the esophagus and closes off the trachea. the bolus must pass through the upper esophageal sphincter (UES) which is normally closed to prevent air from entering the stomach. the bolus is then transported down by peristaltic motion to the lower esophageal sphincter (LES), which is normally closed to prevent gastric reflux.
three types of peristalsis are described: primary peristalsis occurs as a direct reaction to swallowing food. secondary peristalsis occurs even without swallowing- it is initiated when there is already a bolus stuck in the esophagus. tertiary peristalsis occurs in response to stress or loud noise, and contracts the entire length of the esophagus simultaneously- which in effect prevents peristalsis.
when the bolus passes through the LES and into the stomach, it induces "receptive relaxation" and peristalsis in the stomach muscularis layers as well. the stomach generally mixes on the frequency of 3 "constrictor waves" per minute, and includes an action called "retropulsion"- a backwards movement of the gastric contents to aid in mixing. (note: the fundus and body of the stomach can accomodate up to 1.5 L of food)
the last topic in this lecture was vomiting. there are three stages to vomiting: nausea, retching, and vomiting. nausea can be induced by a variety of events such as distention of organs, altered body chemistry, extreme fear or stress, etc. in the GI tract, this is manifested as antiperistaltic motion in the jejunum, relaxing of gastric muscle tone, and eventual reflux of duodenal contents into the stomach. in the next phase, wretching, the stomach contracts and pushes upwards into the thorax, against the closed LES. finally, vomiting occurs when the food gets ejected through the UES.
questions
BER's..
1. what are BER's? what are they generated by?
2. how is an action potential produced from a BER?
3. how is the maximum rate of muscle contraction set?
4. how does depolarization relate to action potential production? what causes depolarization of BER?
5. how does hyperpolarization relate to action potential production? what causes hyperpolarization of BER?
the mouth and esophagus...
6. dysphagia is...
7. what does the uvula do?
8. what does the UES do?
9. what does the LES do?
10. what is the difference between the three types of peristalsis in the esophagus?
11. when is tertiary peristalsis painful?
12. what is the relaxation of LES mediated by?
13. what foods relax LES tone?
gastric motility and emptying...
14. what is the first response of the stomach to the entering bolus?
15. fundus and body can accommodate up to...
16. what is the frequency of gastric mixing?
17. how does stress affect gastric contraction?
18. what is retropulsion?
19. how does fat content relate to gastric contraction
20. how many episodes of gastric reflux does the average person have per meal?
vomiting...
21. three phases of vomiting...
22. what occurs during nausea?
23. what occurs during retching?
24. what might happen due to excessive wretching?
25. what occurs during vomiting?
26. what is the vomiting center in the brain affected by?
27. what is an emetic? what are some examples?
answers
1. basal electrical rhythm, generated by interstitial cells between the circular and longitudinal muscularis mucosa.
2. when the BER reaches the threshold potential, an action potential is initiated.
3. by the slow wave frequency.
4. increases the AP frequency, cased by distention of lumen, parasympathetic and hormonal stimulation.
5. decreases AP frequency, caused by sympathetic activity, NE
6. difficulty swallowing.
7. prevents efflux of food into the nasal pharynx.
8. prevents air from getting into the stomach.
9. prevents gastric secretions from entering esophagus.
10. primary is in response to swallowing food. secondary is peristalsis without swallowing- when something is stuck in the esophagus. tertiary has no known function- can be stimulated by loud noises or stress and contracts the whole esophagus.
11. it can cause chest pain in individuals with esophageal motility problems.
12. vagus nerve, VIP, nitric oxide
13. alcohol, antacids, proton pump inhibitors, mint, chocolate, viagra (by way of NO), opiates, drugs to treat angina, bronchodilators. progesterone.
14. "receptive relaxation"
15. 1.5 L
16. 3 constrictor waves / minute.
17. it can cause contraction of the entire stomach (similar to tertiary esophageal contraction) which blanches blood to the brain/muscles and eventually can cause ulcers.
18. the backward motion of contents (to aid in mixing)
19. causes the gastric contents to mix longer. fats float on top and are emptied last.
20. about 3.
21. nausea, retching, vomiting.
22. relaxing of gastric tone, antiperistalsis begins in the jejunum, and eventual reflux of duodenal contents into stomach.
23. upward contraction of stomach, with LES closed.
24. a hiatal hernia.
25. food gets ejected through UES.
26. distention or irritation of viscera, cerebral events, or altered body chemistry. could be stimulated from GI or kidneys.
27. a substance which induces vomiting, such as ipecacuanha.
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