organ systems: nasal and larynx

this lecture covered the bones, muscles, blood supply, and innervation of the nasal cavity and larynx. it started off with the nasal cavity structures: the nasal cavity is made up of the nasal, maxilla, ethnoid, palatine bones. the nasal septum divides the two nostrils and is made up of the ethmoid, vomer, and septal cartilage. the conchae are curved bones covered with a mucosal layer that serve to increase the surface area of the nasal cavity. the superior concha covers the superior meatus, which is the opening for the frontal sinus. the middle concha covers the middle meatus, which is the opening for the maxillary, ethmoid, and sphenoid sinuses. the inferior concha covers the inferior meatus, which is the site of the nasolacrimal opening.

the nasal cavity is innervated mainly by the mandibular and maxillary divisions of the trigeminal nerve [see diagram]. the anterior ethmoidal nerve branches off of V1 and enters the nasal cavity via the anterior ethmoidal foramen and innervates the anterior ethmoidal sinus, the anterior nasal cavity, and the frontal sinus. V1 also has an external branch that innervates the external nose. V2 comes through the foramen rotundum into the pterygopalatine fossa, and from there into the nasal cavity by way of the sphenopalatine foramina. at this point V2 has three branches that innervate the nasal cavity: 1) greater and lesser palatine branches travel through the palatine foramina and innervate the inferior palate. 2) posterior lateral nasal nerves innervate the concha. 3) nasopalatine branches go through the incisive canal and innervate the inferior aspect of the hard palate. V2 also has an external branch that innervates the exterior of the nasal cavity-- the infraorbital branch innervates the cheek and infraorbital canal and foramina, and the superior alveolar nerve innervates the top row of teeth.

the two major arteries in the nasal cavity are the sphenopalatine and the anterior/posterior ethmoidal arteries. the anterior/posterior ethmoidal branches off of the opthamalic branch of the internal carotid and the sphenopalatine artery branches off of the maxillary branch of the external carotid. it is due to the extensive anatamoses between the blood vessels in this area that nosebleeds are so difficult to stop.

olfactory receptors are bipolar neurons contained in the upper recesses of the nasal cavity that last 1-2 months before being replaced by undifferentiated basal cells. they have ciliated cells called sensory processes that project into the mucous layer which have receptors for specific "odorant" molecules from the environment, which trigger action potential in these neurons by g-proteins and second messenger cascades.

the last section dealt with the larynx muscles and cartilage. the larynx area is made up largely of the thryoid, arytenoid, and cricoid cartilage and also contains the epiglottis, which is attached to the inner surface of the thyroid cartilage. the quadrangular membrane is the connective tissue sheet from the arytenoid cartilage to the epiglottis, while the "conus elasticus" is the connective tissue sheet from the arytenoid/cricoid cartilage to the thyroid cartilage, the upper free edges of which forms the vocal cords.

there are several sets of muscles that control different types of movement in the larynx. the aryepiglottic, thryoepiglottic, and oblique arytenoid muscles close the laryngeal inlet. the posterior cricoarytenoid and lateral cricoarytenoid open the glottis (the space between the vocal cords) while the transverse and oblique arytenoid close it. finally, the cricothryoid lengthens the vocal cords (producing lower pitches) and the thyroarytenoid and vocalis shortens (higher pitches).

questions
nasal cavity and bones...
1. which bones is the nasal aperture made of?
2. what are the types of cartilages in the nose?
3. what is the fleshy part of the nose called and what is it made of?
4. which bones form the walls and the hard palate?
5. what part of the nasal cavity does the ethmoid form?
6. perpendicular plate of ethmoid forms...
7. what passes through the cribiform plate of the ethmoid bone?
8. besides the ethmoid, what else forms the nasal septum?

concha and meatuses...
9. describe the conchae bones.
10. inferior meatus is the site of...
11. middle meatus is the site of...
12. superior meatus is site of...
13. what is an important function of the conchae?
14. what does the respiratory epithelium do?

sinuses...
15. what are the paranasal sinuses?
16. where does the sphenoid sinus open?
17. where is the frontal sinus and where does it open?
18. where is the maxillary sinus and where does it open into?
19. proximity of sinus to maxillary teeth permits...
20. where does the ethmoid sinus open into?

innervation...
21. which nerves are the nasal cavity and hard palate innervated by?
22. describe the passage of the anterior ethmoidal branch of V1 into the nasal cavity.
23. what does the anterior ethmoidal nerve innervate?
24. what does the anterior ethmoidal nerve branch into?
25. describe the passage of the maxillary branch (V2) into the palatine area and the nasal cavity.
26. what does V2 branch into in the nasal cavity area?
27. where do the posterior lateral nerves project?
28. where do the greater and lesser palatine nerves project?
29. where do the nasopalatine nerves project?
30. what are the external branches of V2 and what do they innervate?
31. what is the hay fever ganglion? what nerves does it receive and what nerves does it project?
32. describe the parasympathetic innervation of the nasal cavity.

arteries...
33. what are two of the major arteries in the nasal cavity?
34. where does the anterior/posterior ethmoidal artery branch off of?
35. where does the sphenopalatine artery branch off of?
36. why are nosebleeds difficult to stop?

olfaction...
37. what are olfactory receptors? where are they?
38. what is the live span of a olfactory receptor? what happens when they die?
39. what are "sensory processes" and what do they do?
40. how do odorants trigger an action potential?

larynx and vocal cords...
41. what is the cartilage associated with the larynx?
42. what are some landmarks of the thyroid cartilage?
43. where is the epiglottis attached?
44. what does the thyrohyoid membrane do?
45. what are the vocal cords made of?
46. what is the conus elasticus?
47. what is the space between vocal cords called?
48. what is the quadrangular membrane?
49. what is the vestibular fold?
50. where is the ventricle of the larynx?

muscles and innervation of larynx...
51. what are the muscles that close the laryngeal inlet?
52. what are the muscles that open and close the vocal cords?
53. what are the muscles that lengthen and shorten vocal cords?
54. why do males have lower pitched voices than females?
55. what nerve innervates the larynx?
56. which branch supplies motor innervation to cricothyroid and sensory innervation to the mucosa?
57. which branch supplies motor innervation to all of the other intrinsic larynx muscles?

answers
1. nasal and maxilla
2. lateral, septal, alar
3. ala nasi, made of loose CT
4. maxilla and palate bones
5. the roof and part of the nasal septum.
6. part of nasal septum.
7. olfactory nerves.
8. vomer, septal cartilage.

9. curved bones covered with mucosa that overlie meatuses.
10. nasolacrimal opening (which is why crying produces a runny nose)
11. site of opening of the maxilla, ethmoid, frontal sinuses.
12. site of opening of the sphenoid sinus.
13. increasing surface area of nasal cavity.
14. warms, humidifies, dehumidifies air.

15. cavities within bones: sphenoid, ethmoid, frontal, maxillary.
16. above the superior concha.
17. within frontal bone, deep to the glabella and superior orbital fissure; opens into the middle meatus.
18. within maxilla bone, empties into middle meatus.
19. intercommunication of infections.
20. lateral nasal cavity.

21. V1 and V2.
22. anterior ethmoidal branch of V1 travels into the nasal cavity via the anterior ethmoidal foramen.
23. the frontal sinus, anterior ethmoidal sinuses, and anterior nasal cavity.
24. the external nasal branch which innervates the external nose.
25. enters the pterygopalatine fossa via the foramen rotundum and the nasal cavity via the sphenopalatine foramen.
26. posterior lateral nerves, greater/lesser palatine nerves, nasopalatine nerves.
27. the conchae
28. through the palatine foramina to the inferior palate.
29. into the anterior aspect of the hard palate via the incisive foramen.
30. the infraorbital branch innervates the cheek and infraorbital canal and foramen. the superior alveolar branches innervate the upper teeth.
31. the pterygopalatine ganglion; receives the facial nerve (CN VII) and projects nerves to the nasal, palatine, and lacrimal glands via V1 and V2.
32. preganglionics from the T1 level project to the superior cervical ganglion. postganglionics follow blood vessels to nasal cavity.

33. sphenopalatine and anterior/posterior ethmoidal.
34. from the opthamalic branch of the internal carotid.
35. from the maxillary branch of the external carotid.
36. because of the extensive anastamoses of arteries in the nasal cavity.

37. bipolar neurons within olfactory epithelium in upper recesses of nasal cavity.
38. 1-2 months, replaced by undifferentiated basal cells
39. ciliated cells that project into the mucus layer which have receptors for specific odorants.
40. via G proteins and second messengers.

41. thyroid, arytenoid, cricoid
42. lamina, thyroid notch. superior/inferior horns. laryngeal prominence (adam's apple).
43. inner surface of thyroid cartilage.
44. suspends larynx from hyoid bone.
45. upper free edges of the conus elasticus.
46. CT sheet from arytenoid/cricoid cartilage to thyroid cartilage.
47. rima glottidis.
48. CT sheet from arytenoid cartilage to epiglottis.
49. lower free edge of quadrangular membrane.
50. cavity between vocal and vestibular folds.

51. aryepiglottic, thyroepiglottic, oblique arytenoid
52. posterior cricoarytenoid, lateral cricoarytenoid open glottis, transverse and oblique arytenoid close glottis.
53. cricothyroid lengthens, thyroarytenoid and vocalis shortens.
54. higher testosterone levels elongate the thyroid cartilages and thus produce longer vocal cords and lower voices.
55. vagus
56. superior laryngeal
57. recurrent laryngeal

organ systems: oral and pharynx

this lecture talked about various aspects of the pharynx, including muscles, tonsils, and innervation. the first section covered structures of the mouth and teeth: philtrum is the median shallow groove in the upper lip, labia frenulum is the fold of mucosal membrane that attaches the lip to the gums, and lingual frenulum is the fold that connects the tongue to the base of the mouth. there are 32 teeth, 8 in each half of each jaw: 2 incisors, 1 canine, 2 pre-molar, and 3 molars. the crowns of the teeth are made up of dentine and enamel, and the pulp cavity inside contains nerves and blood vessels, which travel through the tooth in root canals and exit via the apical foramen. teeth are anchored to bone via the cementum and peridontium layers.

there are intrinsic muscles inside the tongue and extrinsic muscles of the tongue that attach to various structures in the pharynx and move the tongue in different directions. this includes the genioglossus, which attaches to the mental spine of the mandible and protrudes and depresses the tongue, the hyoglossus, which attaches to the hyoid bone and depresses the tongue, the styloglossus, which attaches to the styloid process of the mandible and retracts the tongue, and the palatoglossus, which attaches to the soft palate and raises the tongue. the first three tongue muscles are innervated by the hypoglossal nerve (CNXII), and the palatoglossus is innervated by the vagal nerve.

the tongue's sensory innervation can be divided into two aspects: somatosensory innervation delivers pain, touch, heat sensation from the filiform papillae of the tongue, while viscerosensory information delivers the taste information from the chemoreceptors from the valate and fungiform papillae on the tongue. on the top 1/3 of the tongue, both somatosensory and viscerosensory innervation is provided by the glossopharyngeal nerve (CNIX) while in the bottom 2/3 of the tongue, viscerosensory innervation is provided by the facial nerve (CNVII) and somatosensory by the lingual nerve (V3).

the next topic in the lecture was the pharyngeal and palatine muscles. there are several pharyngeal constrictor muscles which constrict the pharynx, all originate from the posterior pharyngeal raphe, and are all innervated by the vagus nerve. the superior constrictor attaches to the buccinator by way of the pteromandibular raphe, the middle constrictor attaches to the hyoid, and the inferior constrictor attaches to the cricoid and thyroid cartilage. the palatine muscles include the palatopharyngeus, which attaches the soft palate to the back of the throat and serves to lower the soft palate and the palatoglossus, which was covered above. the tensor veli palatini (innervated by CN V3), which originates on the base of the skull, hooks around the hamulus and tautens the palate while the levator veli palatini (innervated by the vagus nerve) lifts the palate.

tonsils are masses of lymphoid tissue which are present in 4 main places in the pharynx: the pharyngeal tonsils in the upper nasopharynx, the tubular tonsils near that auditory tube, the lingual tonsils on the posterior tongue, and the palatine tonsils, which are between the palatoglossus and the palatopharyngeus. lymph from these nodes ultimately drains into the deep cervical lymph nodes and into the venous system.

questions
lips and tongue...
1. what is the philtrum?
2. what is the labia frenulum?
3. what is the lingual frenulum?
4. what are sublingual veins used for?

teeth...
5. what are the crowns of teeth made up of?
6. what attaches the root of the teeth to the bone?
7. what is the pulp cavity made up of?
8. how many teeth are there? what are the different types?
9. which nerves innervates the teeth?

origins, insertions, actions, innervations:
10. genioglossus
11. hyoglossus
12. styloglossus
13. palatoglossus

tongue innervation...
14. which tongue muscles does the hypoglossal nerve innervate?
15. what are the two categories of sensory innervation of the tongue?
16. which nerves provide somatosensory and viscerosensory innervation to the lower 2/3 of the tongue?
17. which nerves provide somatosensory and viscerosensory innervation to the upper 1/3 of the tongue?
18. which nerves provide somatosensory and viscerosensory innervation to the palate and epiglottis?
19. what is the difference between the filiform, fungiform, and vallate papillae?

pharyngeal muscles...
20. where do the pharyngeal constrictor muscles all originate?
21. what are the pharyngeal constrictor muscles innervated by?
22. where does the superior constrictor insert?
23. where does the middle constrictor insert?
24. where does the inferior constrictor insert?

palate muscles...
25. how does the soft palate help regulate the passage of air and food?
26. how does the epiglottis help regulate the passage of air and food?
27. tensor veli palatini...
28. levator veli palatini...
29. palatopharyngeus...
30. salpingopharyngeus...
31. snoring is associated with...
32. palatopharyngeus and palatoglossus forms a ... space which contains the ...

tonsils...
33. what is waldeyer's ring?
34. what is unique about the nasopharyngeal tonsils?
35. where is the tubal tonsil located?
36. where is the palatine tonsil located?
37. where is the lingual tonsil located?

nerves and lymph nodes...
38. which nerve innervates the upper section of the oral and nasal cavities?
39. what part of the pharynx does the glossopharygeal nerve innervate?
40. what other sensations or reflexes in the pharynx does the glossopharyngeal nerve mediate?
41. which nerve innervates the lower pharynx and larynx?
42. superficial lymph nodes all drain into...

answers
1. the median shallow groove in the upper lip.
2. folds of mucous membrane that connects the lips to the gingiva.
3. folds of mucous membrane that connects tongue to the base of the mouth.
4. ingestion of medicine directly into the blood.

5. enamel and dentine.
6. cementum and peridontial membrane.
7. a root canal that exits through the apical foramen. also contains nerves and blood vessels.
8. 32 total; 8 in each half of each jaw. 2 incisors, 1 canine, 2 premolar, 3 molar.
9. upper teeth: superior alveolar (V2). lower teeth: inferior alveolar (V3).

10. O: mental spine of the mandible, I: body of tongue, N: hypoglossal (CNXII) A: depress and protrude tongue.
11. O: hyoid bone, I: body of tongue, N: hypoglossal nerve, A: depress tongue.
12. O: styloid process of mandible, I:body of tongue, N: hypoglossal nerve, A: retract tongue.
13. O: soft palate, I: body of tongue, N: vagal nerve, A: elevate tongue.

14. the extrinsic muscles of the tongue (except the palatoglossus) and the intrinsic muscles of the tongue.
15. somatosensory includes tactile, pain, temperature sensation and viscerosensory is the taste sensation.
16. SS: lingual nerve (V3), VS: facial nerve (VII)
17. glossopharyngeal (IX)
18. vagus (X)
19. filiform is pain, temperature, touch receptor; valate and fungiform are taste receptors.

20. the posterior pharyngeal raphe.
21. vagus nerve
22. buccinator via the pteromandibular raphe.
23. hyoid bone
24. thyroid and cricoid cartilage.

25. during breathing it lowers down against the tongue and during eating it raises against the pharyngeal wall.
26. ascends against the tongue during breathing and folds down over larynx during eating.
27. O: pterygoid plates, I: palatine aponeurosis, N: V3, A: tauten palate, open auditory tube.
28. O: base of skull I: pterygoid processes, N: vagus A: raise soft palate and open auditory tubes.
29. O: thyroid cartilage, I: soft palate, N: vagus, A: depress soft palate
30. O: auditory tube, I: pharynx, N: vagus, A: open auditory tubes.
31. obstructions in the soft palate region.
32. triangular space which contains the palatine tonsil.

33. the ring of lymphoid tissue that contains: pharyngeal, tubal, palatine, lingual tonsils.
34. they are the uppermost part of the nasopharynx and can commonly become inflamed (enlarged adenoids) and block the passage of air.
35. near the auditory tube.
36. between the "pillars of fauces".
37. on the posterior surface of the tongue.
38. trigeminal: V2,V3
39. upper pharynx, auditory tube, tonsils
40. gag reflex, sore throat pain.
41. vagus
42. deep cervical lymph nodes.