Test 19 (ocular physiology)
1. The endothelium:
a. maintains the integrity of the corneal stroma through an 
   ATP-Na+, K+-dependent pump

b. receives its nutrient from the blood vessels surrounding the cornea

c. undergoes multiplication in response to trauma

d. contains tight junction between adjacent endothelium

e. produces Descemet's membrane

2. The following are true about the lens:

a. 90% of the weight of the lens is contributed by water.

b. it has no sensory innervation

c. the capsule is thicker posterior than anteriorly

d. it has an equatorial diameter of about 15 mm

e. in eyes dilated with atropine, the thickness of the lens is increased


3. Rod:
a. contains a cilium with a "9+0" configuration.

b. contains 11-trans-retinaldehyde essential for the absorption of photons

c. sheds its outer segment during the day

d. depolarize in response to flashes of light

e. closes its ion channel in response to flashes of light.

4. The tear film:
a. has a higher pH than the serum

b. has a lower concentration of glucose than the serum

c. the oily component is secreted by the meibomian glands

d. the glands of Wolfring secrete the mucous component

e. the glands of Krause secrete the aqueous component


5. The following are water insoluble lens proteins:

a. a crystalline

b. b crystalline

c. g crystalline

d. HM crystalline

e. main intrinsic polypeptide (MIP)


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