L15 larynx and trachea

Question 1

what are the** 3 layers of the cervical viscera **(or viscera of the neck)?

Answer 1

1. endocrine layer-thyroid and parathyroid gland
2. **respiratory layer **- larynx and trachea
3. alimentary layer - pharynx and oesophagus

Question 2

what are the main functions of the respiratory layer of the cervical viscera?

Answer 2

• routing air and food into the respiratory tract and oesophagus respectively
• producing voice
• porviding an airway and a means of sealing it off temporarily (a valve)

Question 3

where is the larynx located in the neck?

Answer 3

• located in the anterior neck
• anterior to the cervical part of the oesophagus

Question 4

at what area of the spine does the larynx sit?

males vs females

Answer 4

• in males it sits at the level of the 3rd to 6th cervical vertebrae
• however in females it sits slightly higher

Question 5

what are the 3 main functions of the larynx?

Answer 5

• breathing
• phonation - producing sounds
• protection of the respiratory system by preventing the swallowing of large matter

Question 6

what is the larynx lined by?

Answer 6

a mucous membrane

Question 7

how many cartilages (unpaired and paired) is the larynx made up of?

Answer 7

• 9 cartilages
• 3 paired
• 3 unpaired

Question 8

what are the** 3 unpaired cartilages?**

Answer 8

1. epiglottis (elastic)
2. thyroid (hyaline)
3. cricoid (hyaline)

Question 9

what are the 3 paired cartilages in the larynx?

Answer 9

1. arytenoid (hyaline)
2. corniculate (elastic)
3. cuneiform (elastic)

Question 10

what is the epiglottis and what is its main function?

Answer 10

• it is a leaf shaped piece of elastic cartilage sitting posterior to the hyoid bone
• functions to prevent food from entering the airways during swallowing

Question 11

what is the cricoid cartilage?

Answer 11

• it is a complete ring of hyaline cartilage between the thyroid cartilage and the trachea

Question 12

what is the purpose of a cricothyrotomy?

Answer 12

the incision made through the skin and cricothyroid membrane to establish a patients airway and allow them them to breath during life threatening circumstances

Question 13

what is an example of an** extrinsic membrane** of the larynx?

Answer 13

• thyrohyoid membrane - connects the superior thyroid cartilage and hyoid bone

Question 14

what are the **2 ligaments **associated with the thyrohyoid membrane?

Answer 14

• the median thyrohyoid ligament - anteromedial thickening of membrane
• lateral thyrohyoid ligament - posterolateral thickening of membrane

Question 15

what are 2 examples of extrinsic ligaments of the pharynx & what structures do they connect?

ie extrinsic group connects parts of the larynx to other structures

Answer 15

• **hyo-epiglottic ligament **- connects the hyoid bone to the anterior aspect of the epiglottis
• cricotracheal ligament - connects the cricoid cartilage to the first tracheal cartilage

Question 16

Describe the cricothyroid membrane / ligament

Answer 16

• intrinsic membrane/ ligament
• originates from the cricoid cartilage and extends superiorly
• the upper part is **thickened **and forms the vocal folds
• the medial part is thicker and forms the **median cricothyroid ligament **

Question 17

What is the quadrangular membrane?

Answer 17

• extends from the** lateral surface of the epiglottis to the arytenoid cartilages**, corniculate and thyroid cartilages
• the lower margin is thickened and forms the **vestibular fold **

Question 18

what is the lateral cricothyroid ligament called?

Answer 18

the conus elasticus

Question 19

what is the function of the laryngeal folds?

Answer 19

they function in airway protection, breathing and phonation

Question 20

what are the** 2 laryngeal folds**?

Answer 20

1. vocal folds
2. vestibular folds

Question 21

Describe the vocal folds

Answer 21

• true vocal cords
• under control by the** muscles of phonation**
• they can be abducted, adducted, relaxed and tensed to control the pitch of sounds

Question 22

describe the vestibular folds

Answer 22

• false vocal cords
• fixed folds - relatively inelastic to protect larynx
• no role in sound production

Question 23

what are rhe 2 groups of muscles in the larynx called?

Answer 23

• intrinsic muscles
• extrinsic muscles

Question 24

what are the extrinsic muscles of the larynx and what ‘subgroups’ are they under?

Answer 24

infra hyoid group
* sternothyroid
* sternohyoid
* thyrohyoid
Supra hyoid group
* mylohyoid
* geniohyoid
* stylohyoid
* digastric muscle

Question 25

what are the functions of the extrinsic muscles?

Answer 25

* to** elevate** the larynx during swallowing * to **depress** the larynx after swallowing

Question 26

what is the function of the cricothyroid muscle? (intrinsic muscle)

Answer 26

* lengthening and stretching the vocal ligaments - creating a high pitch sound

Question 27

what is the function of the thyroarytenoid muscle and vocalis?

Answer 27

to shorten (relax) the vocal cords - make a low pitch

Question 28

what are the 3 intrinsic muscles of the larynx that function to open and close the glottis?

Answer 28

* the posterior cricoarytenoid * lateral cricoarytenoid * transverse and oblique arytenoids

Question 29

what is the specific action of the posterior cricoarytenoid muscles?

Answer 29

they abduct the vocal ligaments - lengthens the vocal cords

Question 30

what is the specific action of the **lateral cricoarytenoid muscles**?

Answer 30

* they adduct the vocal ligaments

Question 31

what is the specific action of the transverse arytenoid muscle?

Answer 31

they adduct vocal ligaments

Question 32

what cranial nerve supplies both motor and sensory innervation to the larynx?

Answer 32

the vagus nerve CNX

Question 33

Describe the **sensory innervation** of the larynx both **above and below the vocal folds**

Answer 33

* above vocal folds - internal laryngeal nerve * below folds - recurrent laryngeal nerve

Question 34

Describe the motor innervation to the instrinsic

Answer 34

instrinsic muscles - recurrent larygneal nerve EXCEPT CRICOTHYROID - supplied by the external laryngeal nerve

Question 35

Describe the blood supply to the upper and lower half of the larynx

Answer 35

upper half - superior laryngeal artery - which is a branch from the superior thyroid artery lower half - inferior laryngeal artery - which is a branch from the inferior thyroid artery

Question 36

Describe the blood supply to the upper and lower half of the larynx

Answer 36

upper half - superior laryngeal artery - which is a branch from the superior thyroid artery lower half - inferior laryngeal artery - which is a branch from the inferior thyroid artery

Question 37

what is phonation?

Answer 37

air passing through the glottis and causing vibration of the vocal folds and sound production

Question 38

what does the **pitch** of the sound produced depend on?

Answer 38

* diameter * length * tension of vocal cords

Question 39

what occurs as the** length **of the vocal cord **increases** vs **decreases** ?

Answer 39

* increase in length -tension increases and the pitch rises * decrease in length - tension decreases and the pitch lowers

Question 40

what is the intensity of the sound (or loudness) related to?

Answer 40

changes in the subglottal air pressure

Question 41

where does the trachea arise from?

Answer 41

arises at the lower border of the cricoid cartilage as a continuation of the larynx

Question 42

what does the trachea bifurate into?

Answer 42

the left and right bronchi

Question 43

Describe the cartilage found in the trachea

Answer 43

* c shaped * hyaline cartilage * posterior part is bridged by trachealis muscle (smooth muscle)

Question 44

Describe the vasculature of the trachea

Answer 44

* bronchial arteries * inferior thyroid arteries * inferior thyroid vein

Question 45

Describe the** innervation of the larynx**

Answer 45

* vagus and recurrent laryngeal nerve - parasympathetic NS * sympathetic NS