Disection VIII: Food Passageways: Oral Cavity Pharynx, Andn Esophagus

Question 1

Spatial relationships of the food passageways and air passageways

Answer 1

They cross each other like an X; air passages is dorsal at level of nose then ventral at level of larynx, the food passage is ventral at level of the mouth/ nose and dorsal at level of larynx

Question 2

Pharynx

Answer 2

Nasopharynx, oropharynx, laryngopharynx

Question 3

Nasopharynx

Answer 3

Dorsal to oropharynx; separated form oropharynx by soft palate; caudal border is the palatopharyngeal arch, rostral boarder is nasal choanae

Question 4

Oropharynx

Answer 4

Ventral to nasopharynx they are separated by soft palate; rostral boarder palatoglossal arch; ventral boarder the area of the palatopharyngeal arch

Question 5

Laryngopharynx

Answer 5

Dorsal to larynx and continued by esophagus

Question 6

Guttural pouches

Answer 6

Extension of Eustachian tube which connects throat and middle ear. Internal and external carotid artery pass along walls as does maxillary artery and sternohyoid bone divides compartment

Question 7

Passage of air in relation to constrictor muscles

Answer 7

Pharyngeal constrictor muscles constrict closing flow to more distal extent of laryngeopharynx; this forces air to travel fro nasopharynx or oropharynx into laryngeal vestibule and caudally into the trachea

Question 8

Passage of a bolus of food or water in relation to pharyngeal constrictor muscles

Answer 8

Bolus deflects either side of the epiglottis and bolus flows to most caudal extend of laryngopharynx bolus is directed caudally with constriction of pharyngeal constrictor muscles crossing pharyngeoesophagel lumen and is propelled into esophagus caudally

Question 9

Pharyngeal muscle functions

Answer 9

Constriction, open pharyngeal lumen to recieve food, elevate palate to close off nasopharynx and function to open the pharyngeal lumen to recieve food, elevate the palate to close off the nasopharynx during swallowing, and facilitate the movement of food into the laryngeopharynx

Question 10

Pharyngeal constrictor muscles

Answer 10

Form an arch dorsal to the lumen of laryngopharynx, key players in act of swallowing; hyopharyngeus, thyropharyngeus, cricopharyngeus; they constrict and relax rostrally to caudally with movements that act synergistically to movements of tounge (recieve bolus of food from tounge and actively propel it down the esophagus)

Question 11

Hyopharyngeus, thyropharyngeus, cricopharyngeus relative positions

Answer 11

Hyopharyngeus most cranial, thyropharyngeus in middle, cricopharyngeus most caudal

Question 12

Innervation of constrictor muscles of pharynx

Answer 12

Innervation from CN IX (glossopharyngeal nerve) and CN X (Vagus nerve); these two nerves form a plexus in region of pharynx

Question 13

Extrinsic muscles of the tounge

Answer 13

Genioglossus, styloglossus, hyoglossus

Question 14

Motor innervation of muscles of tounge

Answer 14

All intrinsic and extrinsic muscles of tounge is by CN XII (hypoglossal nerve)

Question 15

CN XII

Answer 15

Hypoglossal nerve; only function is to innervate tounge, very large; exits the skull via hypoglossal canal and curves rostrally to enter caudal aspect of tounge paralleling border of styloglossal muscle medial to caudal border of mandible

Question 16

Styloglossal muscle

Answer 16

Most lateral of extrinsic tounge muscles, attaches proximal to stylohyoid bone of hyoid apparatus and curves ventrally to attach distally within substance of tounge

Question 17

Muscles of mastication

Answer 17

Digastricus, temporalis, masseter, and ptergoids

Question 18

Muscle for opening jaw

Answer 18

Digastricus

Question 19

Muscles for closing jaw

Answer 19

Temporalis, masseter, pterygoids

Question 20

Pterygoids

Answer 20

Not easily visible because deep to other superfical muscles of mastication

Question 21

Motor innervation to muscles of mastication

Answer 21

By cranial nerve V (trigeminal nerve) specifically mandibular division; exits ventral aspect of skull via oval foramen

Question 22

Salivary glands of the head

Answer 22

Mandibular, sublingual, parotid, and zygomatic

Question 23

Sialography

Answer 23

Radiographic examination of salivary glands; inject contrast medium into salivary duct of single gland followed by x-ray

Question 24

Venous tributaries

Answer 24

Maxillary and linguofacial veins (maxillary dorsal to linguofacial vein); these drain into external jugular vein; mandibular salivary gland runs between them

Question 25

Duct of parotid salivary gland

Answer 25

In very superfical position coursing across masseter muscle

Question 26

Sublingual caruncle

Answer 26

Where ducts of mandibular and sublingual glands open in oral cavity (this is a small elevation of mucosa)

Question 27

Buccal cavity

Answer 27

Ducts of parotid and zygomatic salivary glands open into this; parotid at level of 4th upper premolars and zygomatic by multiple microscopic openings

Question 28

Styloglossus

Answer 28

Most lateral extrinsic lingual muscles; 3 heads insert at different levels along axis of the tounge (caudal rostral sequence these are short, long, and rostral heads) origins: short head arises from distal half of caudal surface of stylohyoid bone; long head arises from stylohyoid bone dorsolateral to origin of short head; rostral head arises from rostrodorsal surface of proximal half of stylohyoid bone; draw tounge caudally and depress it

Question 29

Hyoglossus muscle

Answer 29

Arises from ventrolateral surface of basihyoid and adjacent end of thyrohyoid bone, inserts in root and caudal 2/3 of tounge; action retracts and depresses tounge

Question 30

Genioglossus muscles

Answer 30

Originates from medial surface of mandible; made of 3 bundles vertical bundle (inserts in rostral half of tounge); oblique bundle (inserts on caudal half of tounge); straight bundle (inserts on caudal 1/3 of tounge, basihyoid bone, and ceratohyoid bone); depresses and protrudes tounge

Question 31

Intrinsic muscles of the tounge

Answer 31

Contain superfical longitudinal, deep longitudinal, perpendicular, and transverse muscle fibers

Question 32

Masseter

Answer 32

On lateral surface of ramus of mandible ventral to zygomatic arch; projects beyond ventral and caudal borders of mandible; 3 layers
Superfical- arises from ventral border of rostral half of zygomatic arch, inserts on ventrolateral surface of mandible and ventromedial surface of mandible and on tendinous raphe between masseter and pterygoids us medius
Middle- arises from zygomatic arch medial to origin of superfical layer; inserts in ventral margin of masseter is fossal and area ventral to fossal
Deep layer- some fibers from medial surface zygomatic arch, insert into caudal part of masseter is fossa and ridge adjacent to it some insert along rostral ridge of masseter is fossa
Action- raises mandible in closing the mouth

Question 33

Temporalis

Answer 33

Arises from parietal bone to lesser extend form temporal frontal and occipital bones; insert on coronoid process of manidble
Action- raise mandible in closing mouth

Question 34

Pterygoids

Answer 34

Inserts on medial and caudal surfaces of angular process of mandible; arises from lateral surface of pterygoid palatine and sphenoid bones; Action to raise mandible

Question 35

Digastricus

Answer 35

Ends on ventromedial border of mandible arises from paracondylar process of occiput; action- opens mouth