10/8/2013

10/8/2013

Answers:

Perilymph is rich in ---, Endolymph is rich in---.
A)Na, Cl 
B)Na, K 
C) Cl, Na 
D) Cl, K 
E) K, Na 
F) K, Cl

-Outer = perilymph = sodium rich (similar to CSF)    

-Inner = endolymph = potassium rich (similar to intracellular fluid).  

-A good mnemonic to know is: 

-Peri- structures also end with 'I': vestibuli and tympani.
Therefore, perilymph is in scala vestibuli and scala tympani, and the endolymph is in the scala media.

Name the three nerves that branch off the facial nerve in the temporal bone.

-Greater superficial petrosal: branches off @ geniculate, parasympathetic to lacrimal gland/salivary gland of nose.
-Nerve to Stapedius muscle
-Chorda Tympani (from vertical segment of facial), runs under tympanic membrane

MC Questions:
The apex of the cochlea as a --- mass, a --- stiffness and oscillates at a --- frequency.
A) high, high, low 
B) high, low, high 
C)high, high, high 
D) low, high, high 
E) low, low, high

Free Response Question:
What structure provides energy for the cochlea?

Quick Facts:
Otolaryngology is the oldest medical specialty in the United States.