valves within the larynx Flashcards
ayrepiglottic folds
- bundles of connective tissue and muscle that run from the superior and lateral margins of the epiglottis to the apex of each arytenoid,
- forming a roughly oval-shaped sphincter
- aryepiglottic folds remain open during phonation and respiration, but close for swallowing
- When the muscle contracts the epiglottis is pulled backward, thus covering the entrance to the larynx during swallowing.
ayrepiglottic mms if formed by fibers from…
-the IAs which continue around the apex of the arytenoid and insert into the lateral border of the epiglottis
describe the elastic cuneiform cartilages of the aryepiglottic folds
-elastic cuneiform cartilages are located within these tissues, providing a degree of firmness that enables the aryepiglottic folds to resist the negative pressures of inhalation
False (ventricular) folds composition
- do not extend toward the midline of the laryngeal lumen as far as do the true vocal folds
- composed primarily of connective tissue and some muscle tissue (ventricularis muscle) and form the inferior borders of the quadrangular membrane
- contain numerous mucous glands and goblet cells that help to lubricate the true vocal folds beneath them
false ventricular folds function
- because they contain very little muscle tissue and do not project medially as far as the true vocal folds, it takes a great deal of muscular effort to move the false folds toward the midline
- close the larynx for swallowing as well as for other functions that necessitate a buildup of air pressure within the thoracic cavity, such as excretion, childbirth, and coughing
true VF
- complex structure composed of 5 layers each with different cellular makeup and biomechanics properties
- adduct to close the glottis for swallowing and voiced sound production, and abduct for respiration and voiceless sounds
- attach anteriorly at the anterior commissure of the thyroid cartilage and posteriorly at the vocal process of each arytenoid
laryngeal ventricle
space between false and true VFs
-contains glands that secrete fluid that lubricates the larynx
epithelium
- outermost layer of VFs
- SQUAMOUS, meaning composed of square-shaped cells, stratified, meaning it is composed of more than 1 layer of cells
- NONKERATINIZING, meaning it is not waterproof and therefore can retain moisture, important for ease of vibration without irritation
- tough but still flexible and compliant
- sits on the basement membrane zone which forms the attachment between the epithelium and the next layer: the superficial lamina propria
Superficial layer (reinke’s space)
- composed of loosely organized elastin fibers with a high density of decorin and small amounts of collagen, HA, and FN
- allowing this layer to be very pliable, flexible, and compliant
Intermediate layer
composed of densely organized elastin fibers, the highest concentration of the three layers, and HA, also the highest concentration of the three layers, allowing this layer to be flexible, but less flexible than the superficial layer
deep layer
composed of mostly collagen, some elastin, and some interstitial proteins, allowing this layer to give structural support
Thyroaryntenoid mms
- final and innermost layer of the VF
- composed of muscle tissue of the thyroarytenoid muscle and is more dense and less flexible than the other layers
- still has some degree of compliance.
lamina propria (muscous membrane)
- made up of 3 layers of connective tissue
- superficial, intermediate, and deep
connective tissue
- consists of fibroblasts (living cells) and extra cellular matrix (nonliving cells) ECM
- contains fibrous and interstitial proteins
Fibrous proteins
found in all layers but in different concentrations
- include collagen and elastin
- give shape and form to tissue and ability to withstand stress (i.e. VF vibration)
- provide structural support
interstitial proteins
- provide connection between collagen fibrils
- influences tissue viscosity, thickness (resistance to flow), and vibratory characteristics of the vocal folds
molecules:
- hyaluronic acid (HA)
- fibronectin (FN)
- decorin
hyaluronic acid
- acts as shock absorber influencing the degree of viscosity when VFs slam together
- binds with water and becomes jell-like (flexible)
USED AS SCAR SOFTNER
fibronectin
- involved in wound healing
- need the ability to heal because they’re in a constant state of mild damage and repair
- more FN seen with nodules and polyps
decorin
regulates thickness of collagen fibers
cover body model
- takes 5 layers and groups them into 3 groups based on stiffness
- cover (mucosa), vocal ligament, and body (mms)
cover (mucosa)
- cover of VFs
- epithelium and superficial layer of lamina propria
- most compliant
compliance vs stiffness
Stiffness refers to how strongly a body resists being deformed, displaced, or deflected by an applied force.
The inverse of stiffness is compliance.
The more compliant a body is, the less it resists being moved in some way.
vocal ligament (transition)
-stiffer than the epithelium and SLLP
Body (muscle)
The least compliant layer, the muscle, forms the body of the vocal folds
glottis
space between the VFs
-divided into the membranous and cartilaginous glottis
membranous glottis
over half of the front of the glottis
- 15 mm in males
- 12 mm in females
cartilaginous glottis
under half of back portion of glottis
-4-8 mm in length depending on age/sex/build
paramedian
glottis is slightly open
median
closed glottis
abducted
open glottis
forced abduction
exercise
-VFs open widely for excess ozygen
