UNIT 4: Functions of the larynx and Vagus Nerve Flashcards
for breathing the airway must be open at all ____ valves …. which are:
3
vestibule, false vocal folds, and true vocal folds
during quiet respiration the true VFs are in what position?
intermediate/paramedial position - abducted approx 8mm
during forced respiration the true VFs are in what position?
lateral position - w physcial exertion abduction width doubles
swallowing is a ____ function
protective - failure to protect lungs during swallowing is life-threatening
what must the larynx prevent during swallowing?
the entrance of any substance into the airway, as it would be harmful to the lungs
how do different parts of the larynx prevent substances from entering the airway?
true vocal folds adduct
false vocal folds approximate
arytenoid cartilages are drawn toward the epiglottis
larynx is pulled up against the base of the tongue
epiglottis is deflected
sneezing, coughing, lifting, defecating, and childbirth all require…
build up of alveolar pressure
following inhalation sufficient pressure is generated by _______ and _______ at level of the larynx (laryngeal closure) …. this is called the ______ ______
compression of the thorax
airway resistance
vaslsalva maneurver
the valsalva maneuver increases _____ _____ and can impede _________
intrathoracic pressure
venous return of blood to the heart (pressure on inferior vena cava)
during the Valsalva maneuver the _____ becomes a rigid frame so the forces applied for lifting for ex can be translated to the legs…. if the ____ is not fixed, ____ is depressed by the muscle forces intended for lifting ex.
thorax
thorax, ribcage
what is a cough, how is it innervated?
response of respiratory tissue to an irritant or foreign object
CN X - somatosensory innervation to bronchial mucosa and motor innervation to trachealis muscle
describe how coughing is a violent, broadly-predictable behaviour
- deep inhalation thru widely abducted VFs
- tensing and tight adduction of VFs, elevation of larynx
- High Psub (relaxation pressure +m of expiration) blows VFs apart - maximal flow of air thru airway to clear irritant
If patients are coughing – what does this tell us?
something is going into their airway to stimulate this, we also know there is some preservation of sensory innervation, if they couldn’t feel it they couldn’t cough – even if swallow isnt working the best
chronic irritation from coughing leads to
vocal abuse due to excessive forces generated in coughing
we _____ the larynx for speech - biological functions of the larynx _____
borrow
take precedence
how do the VFs create phonation?
- VFs are masses that can be set into vibration
- VFs intrude into the airway (provides a source of turbulence in the vocal tract)
- vibration of VFs is achieved by placing and holding VFs in airstream so their physical qualities interact w airflow causing vibration
- VFs comprised of muscle and epithelial tissue that is capable of being moved when sufficient force is applied
bernoulli effect
given a constant volume of flow there will be a dec in pressure perpendicular to the flow and inc in velocity at a point of constriction in the flow
w the bernoulli effect, if the tube constricts the volume is the ____ and the velocity ____
same
increases
w the bernouli effect, if the rate of flow ____ at the point of constriction the pressure drops
increases
w the bernoulli effect, at the point of constriction the pressure will ____ and the velocity will ___ if volume is held constant
drop
increase
how does the bernoulli effect relate to vocal fold vibration
- trachea and larynx are the tube
- when the glottis is open and VFs are abducted, not sufficient construction
- adducting VFs produces constriction
- steady volume of air flow from lungs
- benoulli –> low pressure bw VFs so they will be sucked toward midline
what is happening at the glottis during the bernoulli effect?
inc velocity and dec pressure bw folds - folds suck together when pressure drops
as folds contact, instantaneous pressure above VFs drops, while pressure below VFs inc
transglottal pressure differential inc
folds blow apart, air flow begins again
what is the myoelastic aerodynamic theory of VF vibration?
air stream passes bw folds
vibrate as a result of elastic quality of tissue interacting w aerodynamic principles embodied in bernoulli effect
frequency of vibration varies according to VF tension, mass, and elasticity of tissue
how is the valve sys of the VFs used for voiceless consonants?
laryngeal valve opened so that air may flow unobstructed into pharynx and oral cavity (where it is manipulated by articulators)
how is the valving of the VFs used for whispering?
edges of VFs of membranous glottis are stiffened, positioned apart to prevent vibration
vocal processes of arytenoids are toed in (LCA m)
cartilaginous glottis is separated posteriorly to form glottal chink (whisper triangle)
this glottal adjustment allows for air to flow thru the glottis into oral cavity w/o setting VFs into vibration
phonation can occur when the VFs are brought ______ _____ aka _______
brought together medially
aka adduction
phonation is the product of
repeated opening and closing of the glottis (i.e. repeated glottal cycles)
phonation is NOT the product of
repetitive adductions of the VFs
process of drawing the VFs apart to end phonation is
abduction
actual vibration of the VFs is the product of _____ interacting with ____ in the absence of ______
airflow
tissue
repetitive muscle contraction
