Test 147  (Ocular pharmacology)

1. The following are mast cell stabilizers:

a. disodium cromoglycate

b. prednisolone

c. lodoxamide

d. antazoline

e. pheniramine
 

Answer
a.T   b.F   c.T   d.F   e.F
Antazoline and pheniramine are H1-antagonists.

2. The effects of prostaglandins on the eye include:
 

a. increased trabecular outflow of the aqueous

b. disruption of the ocular blood barriers

c. mydriasis

d. vasoconstriction

e. increased vascular permeability
 

Answer
a.F   b.T   c.F  d.F  e.T
Some prostaglandins increased aqueous outflow through the uveoscleral pathway. Other effects of prostaglandins include vasodilatation and miosis.

3. The effects of histamines on the eye include:

a. increasing mucous production

b. decreasing prostaglandin synthesis

c. provoking smooth muscle spasm

d. dilating the conjunctival capillaries

e. chemotactic effect on eosinophils
 

Answera.T  b.F  c.T  d.T  e.T
Histamines stimulates prostaglandin synthesis.

4. The following are chemicals found in local anaesthetics:

a. ketones

b. esters

c. amides

d. ethers

e. nitrous oxide

Answer
a.F   b.T  c.T  d.F  e.F
The chemicals found in local anaesthetics are either amides or esters.

 

5. Supersensitivity of receptors occurs in the following situation:

a. Adie's pupil

b. Horner's syndrome with lesion of the first order neuron

c. Horner's syndrome with lesion of the third order neuron

d. patients on topical guanethidine

e. Argyll-Robertson's pupils

Answer
a.T   b.F  c.T   d.T  e.F
If a tissue loses its nerve supply as a result of, for
example, surgery or trauma, the receptors in that
tissue, lacking stimulation by the natural
neurotransmitter, become supersensitive to both
endogenous and exogenous stimulation. This is seen in Adie's pupil, Horner's syndrome due to lesion of the third order neuron. Supersensitivity can also be induced pharmaceutically such as the use of adrenergic neuron blocker such as guanethidine which causes a hypotensive response to low level of adrenaline.

 

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