Anatomy 7

Question 1

What is the pharynx?

Answer 1

A muscular tube which lies in the neck.
It forms part of the respiratory and gastrointestinal systems.

Question 2

What are the 3 parts the pharynx is composed of?

Answer 2

● The nasopharynx is posterior to the nasal cavity
● The oropharynx is posterior to the oral cavity
● The laryngopharynx is posterior to the larynx (sometimes called the hypopharynx).

Question 3

What are the walls of the pharynx composed of?

Answer 3

Composed of an outer layer of circular muscle and an
inner layer of longitudinal muscle

Question 4

What is the external circular muscle layer in the pharynx composed of?

Answer 4

Composed of three constrictor muscles
- the superior, middle, and inferior constrictors -
that overlap each other.

They contract superior to inferior, so that swallowed food moves down the pharynx towards the oesophagus

Question 5

What happens when food is swallowed?

Answer 5

Food in the oral cavity is pushed into the oropharynx by the
tongue.

The soft palate rises and closes off the nasopharynx from the oropharynx.

Food enters the laryngopharynx and constriction of the muscles of the pharyngeal wall move the food into the oesophagus.

The epiglottis - one of the cartilages of the larynx - closes off the laryngeal inlet and prevents food or liquids from entering the larynx.

Question 6

What is the pharynx innervated by?

Answer 6

The pharynx is innervated by sensory fibres from the glossopharyngeal nerve and motor fibres from the vagus nerve.

Question 7

What nerves are found in the posterior pharyngeal wall?

Answer 7

● The cervical part of the sympathetic trunk and superior cervical ganglion.
● Superior laryngeal nerve. This branch of the vagus nerve descends over the posterior aspect of the internal carotid artery. It passes between the inferior and middle constrictors of the pharynx to the larynx.
● Hypoglossal nerve. This lies close to the vagus nerve
● Glossopharyngeal nerve. From the posterior aspect, it lies deep to the internal carotid artery.

Question 8

What is the larynx made up of?

Answer 8

Composed of several cartilages, membranes, and small muscles.

Question 9

What does the larynx do?

Answer 9

Protects the airway and contributes to phonation/speech.

Question 10

How many cartilages is the larynx composed of?

Answer 10

Composed of nine cartilages.
Three are unpaired, and three are paired.

Question 11

What are the cartilages in the larynx connected by?

Answer 11

Membranes and small joints

Question 12

What are the 3 unpaired cartilages in the larynx?

Answer 12

Epiglottis, thyroid cartilage, and the cricoid cartilage

Question 13

What are the 3 paired cartilages in the larynx?

Answer 13

Arytenoids, the cuneiforms and the corniculate cartilages.

Question 14

What is the thyroid cartilage composed of?

Answer 14

Composed of two flat cartilages (laminae) that meet in
the anterior midline to form the laryngeal prominence, or ‘Adam’s apple’, which is usually visible in males.

Question 15

What does the laminae form?

Answer 15

Forms extensions that project superiorly and inferiorly -
the superior and inferior horns.

Question 16

What the the superior horn attach to?

Answer 16

Hyoid Bone

Question 17

What does the inferior horn articulate with?

Answer 17

Cricoid Cartilage

Question 18

What does the cricothyroid membrane do?

Answer 18

Connects the inferior border of the thyroid and superior border of the cricoid.
This membrane is pierced to create an emergency airway.

Question 19

What is the epiglottis and what does it do?

Answer 19

Attached to the superior aspect of the thyroid cartilage, where the two thyroid laminae meet.

During swallowing, the epiglottis covers the entrance to the larynx (the laryngeal inlet) and protects the airway from the
entry of liquid or food.

Question 20

What is the arytenoids?

Answer 20

Sit on the superior surface of the cricoid cartilage.
They articulate with the cricoid cartilage at small joints

Question 21

What do the arytenoids do?

Answer 21

Vital for phonation, as the vocal cords attach to them
Movements of the arytenoids move the vocal cords.

Question 22

What are the two groups of muscles that act on the larynx?

Answer 22

● Extrinsic muscles - the suprahyoid and infrahyoid muscles. They do not move the individual cartilages, but rather move the larynx as one

● Intrinsic muscles - these small muscles move the individual cartilages of the larynx relative to each other.
By moving the cartilages, they move the vocal cords, and this in turn alters the quality of speech.

Question 23

Where is the hyoid bone located?

Answer 23

Inferior to the mandible

Question 24

Where is the thyroid cartilage located?

Answer 24

In the midline of the neck (Adam’s Apple)

Question 25

Where is the cricoid cartilage located?

Answer 25

In the midline, inferior to the thyroid cartilage

Question 26

Where is the first tracheal cartilage located?

Answer 26

Inferior to the cricoid cartilage

Question 27

Where is the cricothyroid membrane located?

Answer 27

Between the thyroid cartilage and cricoid cartilage

Question 28

Why is the cricothyroid membrane important?

Answer 28

Can be punctured to create an emergency airway

Question 29

Where are the lobes of the thyroid gland located?

Answer 29

Either side of the upper trachea and inferior larynx

Question 30

Where can the carotid pulse be found?

Answer 30

Best palpated just anterior to sternocleidomastoid at the level of the thyroid cartilage

Question 31

What is the purpose of a gag reflex?

Answer 31

Protects the airway.
It is mediated by the glossopharyngeal and vagus nerves.

When the back of the mouth, posterior wall of the pharynx or the tonsils are stimulated, this sensation is carried to the CNS via the glossopharyngeal nerve.

In response, the muscles of the soft palate and pharynx immediately contract (via motor fibres in the vagus nerve).

This reflex does not occur in normal swallowing but does occur at any other time the posterior mouth or pharynx are touched (e.g. swabbing the tonsils).

Question 32

Why may you have swallowing difficulties after a stroke?

Answer 32

If a stroke affects the regions of the brain involved in the control of swallowing, then patients may have swallowing difficulties.

In normal swallowing, the vagus nerve coordinates contraction of the pharyngeal muscles and soft palate and conveys sensation from the larynx.

The glossopharyngeal nerve provides sensory innervation to the pharynx.

If these pathways are interrupted, swallowing is
dysfunctional, and loss of sensation impairs the cough reflex. Patients are at risk of ‘aspiration’ – swallowed liquid or food may pass into the lungs and cause infection.

Question 33

What is the emergency airway?

Answer 33

If the airway is obstructed above the level of the cricoid cartilage (e.g. a foreign body is stuck at the vocal cords, or the vocal cords have become suddenly grossly swollen)
an emergency airway that bypasses the upper airway can be created by piercing the cricothyroid membrane.

This is a lifesaving but temporary measure, and a more
secure airway is established as soon as possible.