Larynx Flashcards by Hebah Mirza

What is the primary role of the larynx?

prevent aspiration of foreign bodies into the lower respiratory system

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How does the position of the larynx change in adults and why?

in infants –> begins at C1, located at the height of the jawbone to allow them to breathe & swallow simultaneously (so they can breathe while breastfeeding)

in adults –> begins at C3, descends & is located in neck –> evolutionary advantage –> can produce certain sounds. Adult humans can’t introduce air while swallowing (

(must elevate larynx & move it anteriorly when swallowing to prevent foreign bodies entering)

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What happens when aspiration of foreign bodies occurs?

action of true & false vocal cords acts as part of the cough reflex mechanism to expel them (water, oral secretion, food, etc)

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What is the main difference b/w chimpanzee & human oral cavity & larynx?

longer oral cavity & much lower larynx in humans

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Which organism has the most primitive larynx?

bichir lungfish (Polypterus) -- in Nile river
consists only of a muscular sphincter

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A communication b/w respiratory & digestive pathways is maintained in adult humans too. True or false & why?

true, bc during development the communication of respiratory diverticulum w/ the future oropharynx is established
result = a crossing b/w these 2 routes as air enters from nasal cavity & food from oral cavity

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Briefly describe the embryological development of the larynx

aperture of larynx = a slit called LARYNGOTRACHEAL GROOVE which opens into the respiratory diverticulum
slit/groove starts to look like a T –> LARYNGEAL INLET

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The cartilage of the larynx derives from the mesodermal mesenchyme of which 2 pharyngeal arches?

4th & 6th

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Where do the intrinsic laryngeal muscles originate from and what’s their innervation?

6th pharyngeal arch

RECURRENT NERVE or inferior laryngeal n (branch of vagal n)

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Which arch does the crico-thyroideus originate from? Innervation?

4th
an intrinsic laryngeal muscle
superior laryngeal n

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Are skeletal muscles of the larynx voluntary or involuntary?

Involuntary, despite being striated –> bc the have branchial/pharyngeal origin

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the larynx is a ____________ canal attached to the ____ bone, it extends from the base of the _____ to the ______ in front of vertebrae C_ to C_

fibrocartilaginous 
hyoid 
tongue 
trachea
C3 to C6

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Which muscles are associated to the hyoid bone?

muscles of the floor of oral cavity &

those that move the larynx

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Which are the 4 large cartilages of the larynx?

THYROID - shield-shape, hyaline cartilage
CRICOID - most caudal, at base of larynx, ring-like, hyaline “
ARYTENOIDS - resemble ampullae, hyaline & elastic “
EPIGLOTTIS - above the glottis, elastic “, most imp functionally –> moved when swallowing

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Which are the 4 large cartilages of the larynx?

THYROID - shield-shape, hyaline cartilage
CRICOID - most caudal, at base of larynx, ring-like, hyaline “
ARYTENOIDS - resemble ampullae, hyaline & elastic “
EPIGLOTTIS - above the glottis, elastic “, most imp functionally –> moved when swallowing

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Which are the 2 small cartilages of the larynx?

CORNICULATE - resemble small horns, associated to superior surf of arytenoid
CUNEIFORM - within a ligamentous device –> QUADRANGULAR MEMBRANE

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The larynx is highly _____, it can be moved down, forward, & backward thanks to the action of ______ muscles

mobile

extrinsic

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What is the function of the false vocal cords?

protective device of region where true vocal cords are –> RIMA GLOTTIS

Posteriorly, the larynx is completed by the ______

pharynx

What are the main features of the cricoid cartilage?

most caudal
in communication w/ the 1st tracheal ring
shape = signet ring
palpated below the laryngeal prominence (Adam’s apple) of thyroid cartilage
2 articular facets
1. inferior –> articulation w/ inf horn of thyroid cartilage
2. superior –> “ w/ arytenoids

Describe the crico-vocal membrane

AKA cricothydois membrane/ligament
closes the space left empty b/w thyroid & cricoid cartilages

boundaries:
- from cricoid’s superior margin to arytenoids’ anterior processes & thyroid cartilage’s internal angle

What is the median cricothyroid ligament?

anterior & medial portion of crico-vocal membrane –> where it is thicker

What action on the vocal ligaments alter the pitch of our voice?

when thyroid cartilage is lifted up –> vocal ligaments stretch –> more tension –> alters pitch of voice

What is the conus elasticus?

the inferior part of the fibroelastic membrane of larynx

delimits an opening in the middle

The epiglottis is a ___-like structure. It attaches where the 2 vocal ligaments converge, on the ______ angle of thyroid cartilage

leaf-like | internal

Which muscles insert on the cricoid cartilage?

A - Intrinsic 1. cricothyroid 2. cricoarytenoid (posterior & lateral) B - Extrinsic 1. cricopharyngeal 2. part of inferior constrictor 3. esophageal longitudinal fibers cricothyroid & thyroarytenoid cover the cricothyroid membranes from the outside

What are the main features of the thyroid cartilage?

- laryngeal prominence on midline from which 2 laminae (plates) extend - thyroid notch --> reference pt for surface anatomy, easily palpable - oblique line --> insertion of extrinsic laryngeal muscles - 2 superior & 2 inferior horns - inferior horn --> articulates w/ inferior facets of cricoid - superior horn --> attachm of lateral THYROHYOID LIGAMENTS

What is another term for the laryngeal prominence?

Adam's apple ;)

What converges at the thyroid angle?

the 2 vocal cords

What is the significance of a more acute/narrower thyroid angle in men?

consequence = laryngeal prominence is more palpable in men | longer vocal cords in men --> lower pitch voice think of guitar strings

Where is the thyrohyoid membrane thicker?

1. anteriorly --> it becomes the median thyrohyoid ligament | 2. laterally & posteriorly --> forming lateral thyrohyoid ligaments

Where are TRITICEAL cartilages found?

within the lateral thyrohyoid ligaments

Which 2 things make the larynx susceptible?

1. airway thru the larynx is an open passage --> need activation of mechanism that closes it by the epiglottis if larynx is not correctly positioned --> anything that enters can proceed to the airways 2. since the larynx has a fibrocartilaginous structure --> its more fragile --> doesn't recover spontaneously from a crush (unlike muscular struc of esophagus)

What are the main features of the epiglottis?

- leaf-like struc - elastic cartilage - connected via thyro-epiglottic ligament to internal angle of thyroid cartilage - does NOT articulate w/ any other cartilage --> so has high mobility

What role of the aryepiglottic folds play in the protective mechanism during swallowing?

- act as rampant to larynx during swallowing --> so food slides down on sides of larynx instead of entering

Where is the quadrangular membrane?

from the free lateral margins of epiglottis --> extends to superior margin of arytenoid cartilage

The free margins of the quadrangular membrane forms the _________ ligaments

vestibular

What is the conus elasticus ?

= floor of the laryngeal inlet - a fibroelastic membrane - AKA cricothyroid membrane - mainly elastic tissue. - anterior and two lateral portions : 1. anterior part or middle cricothyroid ligament (ligamentum cricothyreoideum medium; 2. central part of cricothyroid membrane) is thick and strong, narrow above and broad below

What is the glottis?

the territory b/w the true vocal cords & false vocal cords

False vocal cords = ?

= vestibular ligaments + mucosa

True vocal cords = ?

= vocal ligaments + mucosa

What are the main features of the arytenoids (cartilages)?

- small pyramid-like - 2 processes 1. vocal process -- insertion of vocal ligament/ true vocal cord 2. muscular process - apex --> articular facet for CORNICULATE cartilage

Which are the intrinsic ligaments of the larynx?

they form the fibroelastic membrane of the larynx 1. cricothyoid ligaments/ membrane - forms inferior part of fibroelastic membrane aka CONUS ELASTICUS. - free upper margins form VOCAL ligaments (core of the true vocal cords) 2. quadrangular membrane - formed by aryepiglottic folds - free lower margins form VESTIBULAR ligaments (core of false vocal cords)

Which are the extrinsic ligaments of the larynx?

1. Thyrohyoid membrane - reinforced by lateral & medical thyroid ligaments 2. Thyroepiglottic ligaments - from stem of epiglottis to angle of thyroid cartilage 3. Crico-tracheal ligament - from cricoid to 1st tracheal ring 4. Hyo-epiglottic ligament - from dorsal surf of epiglottis to hyoid