Synaptic Transmission Practice Questions

Question 1

Which of the following is true regarding Na+ (sodium) ions?

Accepted Answer

Responsible for depolarization

Answer

Does not help other ions in transport

Answer

Responsible for the resting membrane potential

Answer

Sodium ion is responsible for Donnan effect

Question 2

Absolute refractoriness of a neuron is due to?

Accepted Answer

Inactivation of Na channels

Answer

Hyperpolarization of Cl channels

Answer

Opening of rectifier K+ channels

Answer

Closure of activated Na channels

Question 3

Mechanism of action of d-tubocurarine is:

Accepted Answer

Competitive, nondepolarizing block at the Nm cholinergic receptor

Answer

Noncompetitive, depolarizing block at the Nm cholinergic receptor

Answer

Non-competitive, nondepolarizing block at the Nm cholinergic receptor

Answer

Competitive, depolarizing block at the Nm cholinergic receptor

Question 4

Sequence the events in neuromuscular action potential conduction:
1. Sodium channels open in the end plate
2. Calcium enters at the nerve terminal
3. Release of acetylcholine

Accepted Answer

$2 \rightarrow 3 \rightarrow 1$

Answer

$1 \rightarrow 2 \rightarrow 3$

Answer

$1 \rightarrow 3 \rightarrow 2$

Answer

$3 \rightarrow 2 \rightarrow 1$

Question 5

Which of the following is true about Lambert-Eaton syndrome?

Accepted Answer

IgG antibodies against voltage-gated calcium channels

Answer

It is a paraneoplastic syndrome associated with squamous cell carcinoma of lung

Answer

There is increase in release of presynaptic acetylcholine

Answer

With continuous stimulation there is marked increase in amplitude of action potentials.

Question 6

Match the following:
A) Glossopharyngeal nerve
B) Spinal accessory nerve
C) Facial nerve
D) Mandibular nerve

1) Shrugging of shoulder
2) Touch sensation from the posterior one-third of the tongue
3) Chewing
4) Taste from the anterior two-thirds of the tongue

Accepted Answer

A-2 , B-1 , C-4 , D-3

Answer

A-3 , B-1 , C-4 , D-2

Answer

A-2 , B-3 , C-4 , D-1

Answer

A-4 , B-1 , C-2 , D-3

Question 7

Primary afferent fibers secrete which nociceptive substance at the dorsal horn?

Accepted Answer

Substance P

Answer

Acetylcholine

Answer

Norepinephrine

Answer

Epinephrine

Question 8

Which of the following is true regarding Lambert-Eaton myasthenic syndrome?

Accepted Answer

Associated with autoantibodies against P/Q-type calcium channels

Answer

Deep tendon reflexes are preserved

Answer

Pyridostigmine can be used as treatment

Answer

It is a presynaptic disorder of the neuromuscular junction that can cause weakness

Question 9

The mechanism of action of botulinum toxin A is best described by:

Accepted Answer

Presynaptic blockade of acetylcholine release

Answer

Slowing of myelinated nerve fiber transmission

Answer

Postsynaptic receptor blockade

Answer

Acetylcholinesterase inhibition

Question 10

Retinal cells which secrete acetylcholine are:

Accepted Answer

Amacrine cells

Answer

Bipolar cells

Answer

Ganglion cells

Answer

Horizontal cells

Synaptic Transmission — MCQs

Synaptic Transmission — MCQs

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