TBL 27: Pharynx & Larynx

Question 1

What are the caudal and cranial boundaries of the pharyngeal foregut?

Answer 1

Caudal: lung bud
Cranial: Oropharyngeal membrane

Question 2

What is the oropharyngeal membrane? What happens after it’s destroyed?

Answer 2

It’s the cranial most boundary that separates the ectoderm lined stomodeum from the endoderm-lined pharyngeal gut

After it’s destroyed, the oral cavity becomes continuous w/ the oropharynx

Question 3

What is the stomodeum?

Answer 3

Primitive oral cavity

Question 4

Describe the oropharynx, nasopharynx, & laryngopharynx. How are they connected? What are they connected to?

Answer 4

Oropharynx is continuous w/ the oral cavity & the laryngopharynx.

Nasopharynx is incompletely divided from the oropharynx and is continuous w/ the nasal cavity

Laryngopharynx is posterior to the trachea and continuous w/ the esophagus

Question 5

What is the fauces? What are its boundaries (superior, inferior, & lateral)?

Answer 5

Fauces is the throat & is the space b/w the oral cavity and the oropharynx

Superior = soft palate 
Inferior = root of the tongue
Lateral = palatoglossal & palatopharyngeal folds

Question 6

What is the piriform recess?

Answer 6

This is a space in the laryngopharynx where food/swallowed objects can get caught

Question 7

What is the tonsilar fossa? Where is it located?

Answer 7

Found between the palatoglossal & palatopharyngeal folds, the tonsilar fossa houses the palatine tonsils

Question 8

What are tonsils? How are they formed?

Answer 8

Tonsils are aggregates of lymphoid nodules that form from activated lymphocytes that come in contact w/ pathogens

Question 9

What are tonsilar crypts? What type of cells do they have?

Answer 9

The non-keratinized stratified squamous cells that invaginate at the site of the tonsilar fossa

Helps to increase the mucous surface contact on the tonsil

Question 10

Where are the pharyngeal tonsils/adenoids located?

Answer 10

This is found in the pharyngeal recess, superior and posterior to the entrance of the auditory tube

Question 11

What is the tonsillar ring of the pharynx?

Answer 11

This is a ring of tonsils consisting of the lingual, pharyngeal/adenoid, & palatine tonsils

Question 12

What muscles form the inner longitudinal muscular sheet? Outer circular muscle layer? Where are they located?

Answer 12

Inner longitudinal = palatoglossus, palatopharyngeus, & stylopharyngeus

Circular = Superior, middle, & inferior pharyngeal sphincters

Superior is in the oropharynx & nasopharynx but middle and inferior are found in the laryngopharynx

Question 13

What are the role of muscles when you swallow?

Answer 13

Step 1: Voluntary. Soft palate and tongue help to move the food from oral cavity into the oropharynx

Step 2: Involuntary & rapid. Soft palate rises to close off the nasopharynx. Simulatenously, the pharynx gets wider & shorter, while the longitudinal muscle sheet along w/ the suprahyoid muscles elevate the larynx

Step 3: Involuntary. Sequential contractions of the circular pharyngeal muscles cause peristaltic contractions that move food into the esophagus.

Question 14

What two nerves travel through the jugular foramen?

Answer 14

CN IX & CN X

Question 15

What are the two sensory ganglia of the glossopharyngeal nerve used for?

Answer 15

one is for the temp, touch, & pain sensations of the posterior tongue

Other is for taste from the posterior tongue

Question 16

What forms the pharyngeal nerve plexus?

Answer 16

Afferent/sensory = CN IX
Efferent/motor = CN X (vagus) + CN IX (glossopharyngeal)

Note: the two motor nerve components are used to move the soft palate & pharyngeal muscles

Question 17

What connects the thyroid cartilage to the hyoid bone? Function?

Answer 17

Thyrohyoid membrane. Facilitates the movement of the larynx up and down by the suprahyoid & infrahyoid muscles

Question 18

What connects the circoid cartilage to the thyroid cartilage?

Answer 18

median circothyroid ligament

Question 19

Difference b/w hyaline cartilage & elastic cartilage

Answer 19

Elastic cartilage is the same as hyaline expect more flexible due to the elastic fibers that it has

Question 20

What are the boundaries of the laryngeal inlet?

Answer 20

Anterior: Epiglottis

Posterior & lateral walls: Ary-epiglottic folds

Question 21

What are the ary-epiglottic folds? What are they made up of?

Answer 21

These are made from mucosa covering ary-epiglottic ligaments that extend from the arytenoid cartilages to the epiglottic cartilage

The ary-epiglottic ligaments are joined together by ary-epiglottic muscles

Question 22

What are the sensory distributions of the internal laryngeal nerve? motor for the external laryngeal nerve?

Answer 22

Internal has sensory to the mucous membranes of the laryngeal vestibule, superior edge of vocal cords, & the middle laryngeal cavity

External has motor to circothyroid muscles & inferior pharyngeal constrictor

Question 23

What are the functions of the laryngeal muscles?

Answer 23

Circothyroids - tense the vocal cords
Lateral circo-arytenoids/ arytenoid (oblique + transverse) -adduct vocal cord
Posterior circo-arytenoid = abduct
thyroarytenoids = relaxes the vocal cords