Three functions of the larynx
three important landmarks on the hyoid bone
The larynx is comprised of nine cartilages
Thyroid cartilage cricoid cartilage arytenoid cartilages (2) cuneiform cartilages corniculate cartilages (2) epiglottis.
Motor signals from the cerebral cortex descend via _________________ to the brainstem.
upper motor neurons
Where do the upper motor neurons synapse on the LMN?
brainstem
CN X provides motor or sensory info?
both
Where is CN X located?
nucleus ambiguus in the medulla
2 branches of CN X that serve the larynx
- recurrent laryngeal nerve (RLN).
The SLN consists of 2 branches:
internal branch
external branch.
The VF is made up of 3 layers.
mucosoa or cover
vocal ligament or transition
thyroarytenoid muscle or body
mucosoa or cover
epithelium
superficial lamina propria
vocal ligament or transition
intermediate lamina propria
deep lamina propria
thyroarytenoid muscle or body
vocalis and muscularis
When does the lamina prorpria develop into a 3 layer structure?
11-15 years old
2 aerodynamic forces that are determinants of VF vibration
2. Negative pressure due to Bernoulli effect
Steps of vibration
What will stiffness do to the mucosal wave?
make it decreased or absent
Healthy VFs will exhibit a healthy mucosal wave that travels _____ to _____ of the way from the lateral portion of the VFs.
1/3 to 2/3
Myoelastic Aerodynamic Theory of Phonation
Types of glottal pressure
Bernoulli Effect- when a gas/liquid flows from a larger passage into a constricted or narrower passage, the velocity of the gas/liquid molecules must _________while the outward pressure of the molecules on the walls of the narrow passage _________.
increase
decreases
Phonation threshold pressure (PTP)
minimum amount of pressure to just get the VFs oscillating (vibrating).
What affects Phonation threshold pressure (PTP)?
stiffness and viscosity.
Tension and stiffness will cause PTP to be ____________.
greater