Test 145  (General physiology)

1. The release of neurotransmitter from synaptic vesicles:

a. takes place by exocytosis

b. is controlled by neuronal calcium influx

c. is quantal

d. requires neuronal sodium ions influx

e. requires neuronal potassium ions efflux
 

Answer
a. T   b.T   c.T   d.F   e.F
Neurotransmitter release from the synaptic vesicles 
occur through exocytosis and involves the influx of calcium ions. Sodium ions influx or potassium ions efflux are not required. The release of the neurotransmitter is quantal.

2. The following are true about acetylcholine:

a. it has a strong affinity for nicotinic receptors

b. is derived from acetyl CoA and choline

c. is synthesized by a reaction involving choline 
    acetyltransferase

d. is inactivated by reuptake

e. is inactivated by hydrolysis to acetyl CoA and choline
 

Answer
a.T   b.T   c.T   d.F   e.F
Acetylcholine release is inactivated by hydrolysis through the action of cholinesterase into choline and acetic acid.

3. The effect of calcium ions on neurotransmitter release at synapses 
    include:

a. vesicular fusion

b. tonic depolarization of the presynaptic neurone

c. post-tetanic potentiation

d. transport of synaptic vesicles to the presynaptic active 
    zone of release

e. reuptake of noradrenaline

Answer
a.T   b.T   c.T   d.T   e.F

4. The neuronal resting membrane of the human brain is :

a. maintained by the sodium pump

b. around -70mV

c. maintained by using ATP for energy

d. achieved by active extrusion of potassium ions out of 
    the neurone

e. maintained by influx of calcium ions
 

Answer
a.T   b.T   c.T   d.F   e.F
The resting membrane is maintained by active extrusion of sodium ions out of the neurone.

5. In rapid eye movement sleep, the following are seen:

a. increased heart rate

b. increased systolic blood pressure

c. decreased respiratory rate

d. increased cerebral flow

e. maximal loss of muscle tone

 
Answer
a.T   b.T   c.F   d.T   e.T
The respiratory rate is increased.
Other features include increased sympathetic activity and transient runs of conjugate ocular movements.

 

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