Station 4: Larynx

Question 1

What are the major functions of the larynx?

Answer 1

Produces sound

Acts as a conduit of air from the laryngopharynx to the trachea

Closes off the airways during swallowing

Question 2

What are the 3 paired cartilages of the larynx?

Answer 2

The Arytenoids, Corniculates, Cuneiforms

Question 3

What are the 3 unpaired cartilages of the larynx?

Answer 3

Epiglottis, Thyroid, Cricoid

Question 4

What is the aditus? What are its’ boundaries?

Answer 4

Aditus is the inlet to the larynx from the laryngopharynx.

Anteriorly: Free edge of the epiglottis

Laterally: Aryepiglottic folds

Posteriorly: Arytenoid cartilages, corniculate cartilages

Question 5

What are the names of the subdivisions of the larynx? What are their boundaries?

Answer 5

Supraglottic cavity:

Extends from the aditus (superiorly) to the glottis (between the true vocal folds)

Infraglottic Cavity:

Extends from the glottic (superiorly) to the first tracheal ring at the end of the larynx (C6/7)

Question 6

What are the names of the cavities 1) above the vestibular folds, 2) between the vestibular folds and the true vocal folds, 3) Below the true vocal folds?

Answer 6

1) Vestibule (of the supraglottic cavity)
2) The ventricle
3) Infraglottic cavity

Question 7

What is the rima vestibuli?

Answer 7

The space between the vestibular folds (false vocal folds).

Question 8

What is the Rima glottidis?

Answer 8

Space between the true vocal folds

Question 9

What is the glottis?

Answer 9

The combination of the rima glottidis and the true vocal folds themselves

Question 10

What are the true vocal folds attached to?

Answer 10

The arytenoid cartilages (posteriorly) and the thyroid cartilage (anteriorly)

Question 11

What muscle is the true vocal fold composed of? and what is its epithelium?

Answer 11

Vocalis muscle (thyroarytenoid muscle). Edges of the true vocal folds are stratified squamous epithelium (as they open and close, thus get damaged more)

Question 12

Which muscle adduct the true vocal folds?

Answer 12

Lateral Cricoarytenoids and Transverse Arytenoids

Question 13

Which muscles abduct the vocal folds?

Answer 13

Posterior Cricoarytenoids

Question 14

What function does the vocalis muscle serve?

Answer 14

Adjusts tension on the vocal folds

Question 15

Lowering and Raising the pharynx - which muscles?

Answer 15

Suprahyoid and Infrahyoid muscles

Question 16

What are the vocal fold’s resting position?

Answer 16

Abducted, to allow breathing

Question 17

What does the cricothyroid muscle do?

Answer 17

Tilts thyroid anteriorly

Question 18

What does the thyroarytenoid muscle do?

Answer 18

Shortens the vocal folds, decreasing tension, and lowering pitch

Question 19

What does vocalis muscle do?

Answer 19

Limits the vibration of the vocal folds, affecting the pitch of the voice

Question 20

What muscles help to narrow the laryngeal inlet to prevent food or drink entering the larynx?

Answer 20

Oblique Arytenoid, Aryepiglottic, Thyroepiglottic muscles

Question 21

Which cranial neve supplies motor and sensory innervation to the larynx?

Which 2 specific branches of this nerve supply the larynx?

Answer 21

Vagus: CN X

The L & R Recurrent Laryngeal Nerves

Superior Laryngeal Nerve

All muscles supplied by the recurrent laryngeal nerve

Except cricothyroid which is innervated by the superior laryngeal nerve

Question 22

Which nerves, and what areas of the larynx, provide sensory innervation?

Answer 22

Everything above the true vocal fold = superior laryngeal nerve

Everything below the true vocal fold = Recurrent Laryngeal nerve

Question 23

Why are there two types of epithelia on the epiglottis? What are they?

Answer 23

The inferior portion of the epiglottis is respiratory epithelium.

The superior surface is stratified squamous.

This is because the superior surface comes in contact with swallowed food and liquid, as the epiglottis shuts over the larynx to prevent food entry into the larynx. As such, this surface is prone to abrasion from swallowed substances, thus has adapted a more ‘protective’ stratified squamous epithelium.

Question 24

What type of gland(s) is present in the lamina propria of the respiratory mucosa?

Answer 24

Mucous secreting acini with serous demilunes

Question 25

What type of tissue forms the central support of the epiglottis?

Answer 25

Elastic cartilage

Question 26

Explain the functional reason for the different epithelial coverings of the true and false vocal cords

Answer 26

Stratified squamous epithelium covers the true vocal cord where they meet in the middle of the glottis. This is because they constantly open and close and require a more durable epithelium than the respiratory epithelium