UNIT 4: Structures of the Larynx Flashcards
The larynx is a controlled ____ mechanism, what are its 4 functions?
valving
open for ventilatory pathway
closed for airway protection
closed for inc intrathoracic pressure
midline approximation for voicing (phonation
Is the hyoid bone a part of the larynx?
no - it is technically not a part of the larynx but it is a close relative, needed for the function of the larynx
what material is the larynx made of?
cartilage! held together by a series of ligaments and membranes
7 components of the cartilaginous framework of the larynx (look at neumonic on slides)
- thyroid
- cricoid
- arytenoid (2)
- corniculate (2)
- triticeal (2)
- epiglottis
thyroid cartilage has _____ plates of ________, forms ____ and _____ walls of the neck, sits between ______ and _____
2 fused plates of hyaline cartilage
forms anterior and lateral walls of neck
sits between hyoid bone and cricoid cartilage
cricoid cartilage are a complete _______, sit atop the _____, ______ to thyroid cartilage
ring of hyaline cartilage
sits atop the trachea
inferior to thyroid cartilage
cricoid cartilage often called a _____ ring, where the band sits facing _____
signent ring - band faces forward, big part posteriorly
arytenoid cartilages are ____ _____ shaped _____ ______, sit atop _______ of ______ of the _______
paired pyramidal shaped hyaline cartilages
sit atop superior border of posterior quadrate lamina of the cricoid
what are the 3 ways the arytenoids can move?
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
how do the arytenoids move during speech?
likely use all 3 types of movement
corniculate, cuneiform, and triticial differ from arytenoid, cricoid, and thyroid in what way
elastic cartilages whereas the other 3 are hyaline
describe corniculate cartilages
small, conical elastic cartilages
apex of arytenoids
describe cuneiform cartilages
elongated rods of elastic cartilage
embedded in aryepiglottic folds
aryepiglottic folds
membrane that extends from the top of the arytenoids to the glottis
describe triticial cartilages
small spherical elastic cartilages
embedded in lateral thyrohyoid ligaments
describe the epiglottis structure, what type of cartilage is it?
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
what is the function of the epiglottis?
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
describe the hyoid bone
floating, horseshoe-shaped bone
sits horizontally in anterior neck at level of C3
3 structural features of the hyoid bone
corpus
greater cornua
lesser cornua
describe the folding of the embryro to get to the pharyngeal apparatus
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
what is the pharyngeal apparatus?
series of arches, clefts, and pouches that give rise to head and neck
where does the pharyngeal apparatus dev on the embryo?
arises externally at the anterior end of the embryo around the upper end of the foregut (primitive pharynx)
the pharyngeal/branchial arches are … how many of them?
- mounds of tissue on the lateral sides of the embryo
- arches 1 to 6 dev in humans (5 disappears)
how are the pharyngeal/branchial arches lined internally and externally? whats in the middle?
each arch is lined internally by endoderm and externally by ectoderm, mesoderm and neural crest cells in bw
pharyngeal/branchial arches 1-6 are important for? 4 and 6 specifically dev into what?
1-6 = head and neck dev
4+6 = larynx dev
each pharyngeal/branchial arch gives rise to 4 components:
- musculature (mesoderm)
- vasculature (mesoderm)
- cartilaginous/skeletal (ectoderm)
- nervous (neural crest cells)
formation of the larynx: the pharynx begins to form behind the ______
buccopharyngeal membrane
describe the buccopharyngeal membrane, what happens to it later in dev?
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
formation of the larynx: at week 3, a ______ becomes visible in the floor of the pharynx, between ___ and ___ arches
laryngotracheal groove
4th and 6th
formation of the larynx: the laryngotracheal groove deepens, and edges of the groove form the _____
laryngotracheal tube
formation of the larynx: the ____ end of the laryngotracheal tube becomes the ____, the remainder forms the _____ and ____
cranial
larynx
trachea and lungs
formation of the larynx: what 2 things appear on either side of the laryngotracheal groove?
2 arytenoid swellings
formation of the larynx: how do the 2 arytenoid swellings continue to dev? what does it close?
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
formation of the larynx: when the laryngeal lumen (opening) is re-established what is visible?
false and true vocal folds
formation of the larynx: what do the arytenoid swellings differentiate into?
arytenoid and corniculate cartilages, and aryepiglottic folds
formation of the larynx: what fuses to form the thyroid cartilage?
2 lateral plates from the ventral ends of the 4th arch fuse at midline by a fibrous membrane
formation of the larynx: the cricoid cartilage arises from?
the 6th arch along w arytenoids
what is a laryngectomy?
- 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
laryngeal cleft is?
- 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
