UNIT 4: Structures of the Larynx

Question 1

The larynx is a controlled ____ mechanism, what are its 4 functions?

Answer 1

valving

open for ventilatory pathway
closed for airway protection
closed for inc intrathoracic pressure
midline approximation for voicing (phonation

Question 2

Is the hyoid bone a part of the larynx?

Answer 2

no - it is technically not a part of the larynx but it is a close relative, needed for the function of the larynx

Question 3

what material is the larynx made of?

Answer 3

cartilage! held together by a series of ligaments and membranes

Question 4

7 components of the cartilaginous framework of the larynx (look at neumonic on slides)

Answer 4

• thyroid
• cricoid
• arytenoid (2)
• corniculate (2)
• triticeal (2)
• epiglottis

Question 5

thyroid cartilage has _____ plates of ________, forms ____ and _____ walls of the neck, sits between ______ and _____

Answer 5

2 fused plates of hyaline cartilage

forms anterior and lateral walls of neck

sits between hyoid bone and cricoid cartilage

Question 6

cricoid cartilage are a complete _______, sit atop the _____, ______ to thyroid cartilage

Answer 6

ring of hyaline cartilage

sits atop the trachea

inferior to thyroid cartilage

Question 7

cricoid cartilage often called a _____ ring, where the band sits facing _____

Answer 7

signent ring - band faces forward, big part posteriorly

Question 8

arytenoid cartilages are ____ _____ shaped _____ ______, sit atop _______ of ______ of the _______

Answer 8

paired pyramidal shaped hyaline cartilages

sit atop superior border of posterior quadrate lamina of the cricoid

Question 9

what are the 3 ways the arytenoids can move?

Answer 9

glide away from each other and towards each other

rotate- vocal processes come together at the midline or abduct and move away from each other (twist about the central axis w/i each arytenoid)

rock back and forth like sitting on top of a fence - vocal processes come closer together

Question 10

how do the arytenoids move during speech?

Answer 10

likely use all 3 types of movement

Question 11

corniculate, cuneiform, and triticial differ from arytenoid, cricoid, and thyroid in what way

Answer 11

elastic cartilages whereas the other 3 are hyaline

Question 12

describe corniculate cartilages

Answer 12

small, conical elastic cartilages
apex of arytenoids

Question 13

describe cuneiform cartilages

Answer 13

elongated rods of elastic cartilage
embedded in aryepiglottic folds

Question 14

aryepiglottic folds

Answer 14

membrane that extends from the top of the arytenoids to the glottis

Question 15

describe triticial cartilages

Answer 15

small spherical elastic cartilages
embedded in lateral thyrohyoid ligaments

Question 16

describe the epiglottis structure, what type of cartilage is it?

Answer 16

spoon-shaped elastic cartilage
extends obliquely from internal surface of thyroid angle
has a stem called a petiolus which sits in the midline of the thyroid cartilage
top is connected to hyoid bone via a ligament

Question 17

what is the function of the epiglottis?

Answer 17

valving of laryngeal inlet

want the epiglottis to be moveable bc it can protect the airway but still be pined to hyoid bone so that it doesn’t cover the airway

Question 18

describe the hyoid bone

Answer 18

floating, horseshoe-shaped bone

sits horizontally in anterior neck at level of C3

Question 19

3 structural features of the hyoid bone

Answer 19

corpus
greater cornua
lesser cornua

Question 20

describe the folding of the embryro to get to the pharyngeal apparatus

Answer 20

3 layers - ectoderm on top, mesoderm in the middle, endoderm on the bottom

embryo starts to fold w the head and tail moving towards each other but they do not fuse - hamburger style

then the embryo folds hotdog style, the ectoderm and mesoderm and fuses - aka layers folding towards the midline

Question 21

what is the pharyngeal apparatus?

Answer 21

series of arches, clefts, and pouches that give rise to head and neck

Question 22

where does the pharyngeal apparatus dev on the embryo?

Answer 22

arises externally at the anterior end of the embryo around the upper end of the foregut (primitive pharynx)

Question 23

the pharyngeal/branchial arches are … how many of them?

Answer 23

• mounds of tissue on the lateral sides of the embryo
• arches 1 to 6 dev in humans (5 disappears)

Question 24

how are the pharyngeal/branchial arches lined internally and externally? whats in the middle?

Answer 24

each arch is lined internally by endoderm and externally by ectoderm, mesoderm and neural crest cells in bw

Question 25

pharyngeal/branchial arches 1-6 are important for? 4 and 6 specifically dev into what?

Answer 25

1-6 = head and neck dev

4+6 = larynx dev

Question 26

each pharyngeal/branchial arch gives rise to 4 components:

Answer 26

• musculature (mesoderm)
• vasculature (mesoderm)
• cartilaginous/skeletal (ectoderm)
• nervous (neural crest cells)

Question 27

formation of the larynx: the pharynx begins to form behind the ______

Answer 27

buccopharyngeal membrane

Question 28

describe the buccopharyngeal membrane, what happens to it later in dev?

Answer 28

a seal where the mouth will be - eventually this membrane ruptures meaning that amniotic fluid can flow thru the membrane and this will start a cascade of dev

Question 29

formation of the larynx: at week 3, a ______ becomes visible in the floor of the pharynx, between ___ and ___ arches

Answer 29

laryngotracheal groove
4th and 6th

Question 30

formation of the larynx: the laryngotracheal groove deepens, and edges of the groove form the _____

Answer 30

laryngotracheal tube

Question 31

formation of the larynx: the ____ end of the laryngotracheal tube becomes the ____, the remainder forms the _____ and ____

Answer 31

cranial
larynx
trachea and lungs

Question 32

formation of the larynx: what 2 things appear on either side of the laryngotracheal groove?

Answer 32

2 arytenoid swellings

Question 33

formation of the larynx: how do the 2 arytenoid swellings continue to dev? what does it close?

Answer 33

continue to enlarge, form a T shaped cleft/opening

continued growth closes of the laryngeal entrance - remains occluded until 3rd month of dev when the lumen is re-established

Question 34

formation of the larynx: when the laryngeal lumen (opening) is re-established what is visible?

Answer 34

false and true vocal folds

Question 35

formation of the larynx: what do the arytenoid swellings differentiate into?

Answer 35

arytenoid and corniculate cartilages, and aryepiglottic folds

Question 36

formation of the larynx: what fuses to form the thyroid cartilage?

Answer 36

2 lateral plates from the ventral ends of the 4th arch fuse at midline by a fibrous membrane

Question 37

formation of the larynx: the cricoid cartilage arises from?

Answer 37

the 6th arch along w arytenoids

Question 38

what is a laryngectomy?

Answer 38

• surgical removal of larynx
• oral cavity is sealed off from airway, now only part of the digestive tract
• breath thru stoma
• often bc of cancer or radiation for cancer causing the larynx to be nonfunctional

Question 39

laryngeal cleft is?

Answer 39

• congenital anomaly of larynx
• posterior aspect of the larynx is formed by the arytenoids and cricoid cartilage
• cleft in dev can result in communication bw the esophagus and larynx or trachea
• can affect breathing, swallowing, and voice production
• some not severe, some severe that may not be viable