The pharynx and guttural pouch

Question 1

What 3 components make up the pharynx

Answer 1

• Nasopharynx
• Oropharynx
• Laryngopharynx

Question 2

What are the boundaries of the pharynx

Answer 2

• Dorsally= base of the skull and first few cervical vertebrae
• Ventrally= Larynx
• Laterally= pterygoid muscles, mandible, dorsal part of the hyoid apparatus

Question 3

Where does the nasopharynx extend from and to

Answer 3

Extends from the choanea to intrapharyngeal opening

Question 4

What is the choanea

Answer 4

The opening of the nasal cavity into the nasopharynx

Question 5

What is the nasopharynx lined with

Answer 5

Respiratory epithelium

Question 6

What are the borders of the nasopharynx

Answer 6

• Base of skull
• Soft palate
• Cranial cervical vertebrae

Question 7

Where does the oropharynx extend from and to

Answer 7

Extends from the oral cavity (last molar) to the epiglottis

Question 8

What is the oropharynx lined with

Answer 8

Stratified squamous epithelium

Question 9

What are the borders of the oropharynx

Answer 9

• Tongue
• Palate
• Palatoglossal arches (ridges in the lateral pharyngeal wall created by the right and left palatoglossus muscles

Question 10

Where does the laryngopharynx run from and to

Answer 10

From the intrapharyngeal opening to the opening of the oesophagus and larynx

Question 11

Where does the soft palate extend to in the horse? What does this mean?

Answer 11

• All the way to the epiglottis
• The horse has no laryngopharynx and no space in front of their epiglottis for air to travel which is why they are obligate breathers

Question 12

What is the soft palate covered by

Answer 12

Respiratory and stratified squamous epithelium

Question 13

What is the muscle called that raises the soft palate?

What processes does it have a function it?

Answer 13

• Levator veli patlatine

- Swallowing and mouth breathing

Question 14

What is the name of the muscle that causes tension in the soft palate

Answer 14

Tensor veli palatini

Question 15

What are the 3 muscles that contribute to the pharyngeal wall that are responsible for constriction and shortening of the pharynx

Answer 15

• Palatopharyngeal muscle
• Hypopharyngeal muscle
• Thyropharyngeal muscle

Question 16

What nerves are the striated muscles of the pharyngeal wall innervated by

Answer 16

• Vagus nerve

- Hypoglossal nerve

Question 17

What are the steps of deglutition

Answer 17

• Contraction of the tongue pushes the food into the oropharynx
• Soft palate is elevated resulting in nasopharynx being sealed off from the oropharynx and laryngopharynx
• Larynx elevates resulting in the epiglottis blocking the trachea

Question 18

What are the guttural pouches

Answer 18

The guttural pouches are paired ventral diverticulae of the eustachian (auditory) tubes, formed by escape of mucosal lining of the tube through a relatively long ventral slit in the supporting cartilages

Question 19

Where does the auditory tube (and therefore the guttural pouch in horses)run from and to

Answer 19

Runs from the nasopharynx to the middle ear

Question 20

What are the 2 cavities the guttural pouch is divided into and what structure is responsible for this division

Answer 20

Divided into medial and lateral compartments by the stylohyoid bone

Question 21

What is thought to be the function of the guttural pouch in horses

Answer 21

Cooling of the cerebral blood supply due to extensive contact between the internal carotid artery and the thin pouch walls

Question 22

What are some important adjacent/ neighbouring structures to the guttural pouch

Answer 22

• Cranial nerves 9, 10, 11
• Internal carotid artery
• Cranial nerve 7
• Internal maxillary artery
• Pharyngeal lymph nodes

Question 23

What is a potential complication of draining the guttural pouch if you place the catheter wrong

Answer 23

If the catheter is passed through the middle meatus instead of the ventral meatus, you will hit the ethmoid region which will cause alot of bleeding