Test 115  (Ocular physiology)
1. With regard to the choroid: 
a. the choroid receives 85% of blood flow to the eye

b. the blood vessels in the choroid contains tight junction

c. the choroid vessels are embedded in a matrix made up
    of type III collagen

d. in the presence of high partial pressure of carbon 
   dioxide the choroidal vessels increase in diameter

e. more than 50% of oxygen is extracted from blood 
    passing through the choroid

2. True statements about the pupil include:
a. mydriasis decreases optical aberration

b. it is controlled mainly by the autonomic system

c. miosis increases the depth of focus for near vision

d. a change in the pupil diameter from 2 to 8 mm 
    increases the amount of light entering the eye 
    by 16-fold

e. miosis occurs when the short ciliary nerve is stimulated

3. The following are true about iris:
a. it receives 5% of total blood flow

b. it contains blood vessels with radial coils

c. it contains fenestration in the blood vessels

d. the sympathetic activity in the iris dilator muscles  
    is mainly mediated by b receptors

e. the dilator muscles of the iris are continuous with the 
    outer layer of ciliary body pigmented epithelial cells

4. True statements about the retinal blood flow include:
a. the retina receives 5% of total ocular blood flow

b. the retinal blood flow is mainly under the sympathetic

c. the retina blood vessels are impermeable to ascorbate

d. the pericytes control the contractile activity of the retinal 
    blood vessels 

e. the flow rate in the retinal blood vessels is about 

5. The following are true about the aqueous:

a. the protein content of aqueous is about 1/5 that of 
    the plasma

b. the main type of protein found in the aqueous is 

c. Ig G is found in the aqueous

d. stimulation of a2 receptors reduces aqueous 

e. stimulation of b2 receptors of the ciliary body increases 
    aqueous secretion

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