a. it is a reversible cholinesterase

b. it does not penetrate the blood-brain barrier

c. it acts on the muscarinic receptors

d. it acts on the nicotinic receptors

e. it causes miosis

Answera.T   b.F   c.T   d.T   e.T
It is highly lipid-soluble and can therefore penetrate the blood-brain barrier easily. It acts on both the muscarinic and nicotinic receptors.

2. Physostigmine:

a. causes accommodative spasm

b. causes conjunctival vasoconstriction

c. increases the intraocular pressure

d. causes twitching of the eyelids

e. can be used in infestation caused by pubic lice

Answera.T   b.F   c.F   d.T   e.T
It causes miosis and accommodative spasm. Other effects include conjunctival vasodilatation, lowering of the intraocular pressure and twitching of the eyelids. It can be used to kill of Phthirus pubis.
 

a. is an alkaloid derived from plant

b. is a direct acting muscarinic agonist

c. causes contraction of the longitudinal muscles of the ciliary 
    body

d. worsens myopia

e. has a greater effect on patients with blue iris than brown iris.

Answera.T   b.T   c.T   d.T   e.T
Pilocarpine is bound to the pigment and therefore its effect is reduced in patients with brown iris.
 

a. decreases conduction of nerve impulses

b. has an anaesthetic effect on the cornea

c. is a direct stimulator of the adrenergic receptors

d. causes tachycardia

e. causes increased blood pressure

Answera.T   b.T   c.F   d.T   e.T
It blocks noradrenaline re-uptake and therefore increases the amount of noradrenaline available to stimulate the nerve endings.
It causes mydriasis, vasoconstriction, raised blood pressure and tachycardia.
 

a. thymoxamine

b. guanethidine

c. carbachol

d. neostigmine

e. ecothiophate

Answera.T   b.T   c.F   d.F   e.F
Carbachol is a direct cholinergic stimulator.
Neostigmine stimulates both the muscarinic and nicotinic receptors.
Ecothiophate is an irreversible cholinesterase inhibitor.