Test 139  (Physiology)

1. The following are neurotransmitters at the autonomic post-ganglionic 
    nerve endings:

a. GABA

b. noradrenaline

c. acetylcholine

d. 5 HT

e. glycine
 

Answer
a.F   b.T   c.T   d.F   e.F
The neurotransmitters at the post-ganglionic nerve endings is acetylcholine for the parasympathetic 
system and noradrenaline for the sympathetic system 
except sympathetic fibres to sweat glands which produce acetylcholine.

2. The following are neurotransmitters in the autonomic ganglia:
 

a. GABA

b. noradrenaline

c. acetylcholine

d. 5 HT

e. glycine

Answer
a.F   b.F   c.T   d.F  e.F
The neurotransmitter at all autonomic ganglia is acetylcholine.

3. An increase in PaCO₂ lead to:

a. hypertension

b. increased adrenaline release

c. increased sweating

d. increased insulin secretion

e. mydriasis

Answera.T  b.T  c.T  d.F  e.T
An increased of PaCO2 increases cathecolamine 
secretion and the resultant increase in sympathetic activity lead to hypertension, tachycardia, increased 
sweating and mydriasis. Glucagon secretion is increased.

4. Stimulation of the beta (b) receptors give rise to:

a. tachycardia

b. increased myocardial contraction

c. vasoconstriction of visceral vessels

d. pupil dilatation

e. increase in intracellular cAMP

Answer
a.T   b.T  c.F  d.F   e.T
Pupil dilatation and vasoconstriction are mediated by alpha receptors.

5. Valsalva manoeuvre causes:

a. increased peripheral resistance

b. raised in intraocular pressure

c. drop in blood pressure

d. tachycardia

e. increased blood volume in systemic circulation

 
Answer
a.T   b.T  c.T  d.T   e.T
During Valsalva manoeuvre, there is an increase in 
intrathoracic pressure which compresses the central 
veins resulting in reduced preload and cardiac out. 
The baroreceptor output is inhibited resulting in a 
tachycardia and increased peripheral vascular resistance.

 

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