This document contains 15 multiple choice questions about physiology concepts related to synapses and the neuromuscular junction. The questions cover topics like the types of synapses that can produce excitatory or inhibitory effects; the mechanism of action of inhibitory synapses; characteristics of electrical and chemical synapses; factors involved in spatial and temporal summation; enzymes involved in acetylcholine breakdown; ions involved in acetylcholine release; and the mechanism of action of drugs used to treat myasthenia gravis.

1. 1st Year MBBS Physiology

2. 1.Which type of synapse can produce both excitatory and inhibitory
effects on the post synaptic neurons?
a. Chemical synapse
b. Electrical synapse
c. Excitatory synapse
d. Inhibitory synapse
e. Mixed synapse

3. 2.Which type of synapse requires the binding of neurotransmitters to
specific receptors on the post synaptic membrane?
a. Chemical synapse
b. Electrical synapse
c. Electrochemical synapse
d. Excitatory synapse e. Inhibitory synapse

4. 3.At inhibitory synapse, the post synaptic inhibitory potential is
produced by:
a. Influx of chloride ion in post synaptic membrane
b. Influx of chloride ion in pre synaptic membrane
c. Influx of potassium ion in post synaptic membrane
d. Influx of sodium ion in post synaptic membrane Out flux of
potassium ion in presynaptic membrane

5. 4.Electrical synapse are characterized by
a. Chemical signaling
b. Gap junctions
c. Neurotransmitter release
d. Synaptic cleft
e. Synaptic vesicles

6. 5.When many excitatory potential from one neuron triggers the
threshold point it is called
a. Accomodation
b. Convergence
c. Divergence
d. Spatial Summation
e. Temporal summation

7. 6.At excitatory synapse, the post synaptic inhibitory potential is produced
by:
a. Influx of chloride ion in post synaptic membrane
b. Influx of chloride ion in pre synaptic membrane
c. Influx of potassium ion in post synaptic membrane
d. Influx of sodium ion in post synaptic membrane
e. Out flux of potassium ion in presynaptic membrane

8. 7. The enzyme responsible for break down of acetylcholine in the
synaptic cleft is called:
a. Acetylcholinesterase
b. Acetyltransferase
c. Choline acetyltransferase
d. Decarboxylase
e. Monoamine oxidase

9. 8. which type of synapse has the shortest synaptic delay
a. Chemical synapse
b. Electrical synapse
c. Excitatory synapse
d. Inhibitory synapse
e. Mixed synapse

10. 9.The release of acetylcholine at the neuromuscular junction is triggered
by the influx of which ion into the motor neuron at pre synaptic terminal
a. Both calcium and potassium ion
b. Calcium ion
c. Chloride ion
d. Potassium ion
e. Sodium ion

11. 10. A 43year old man with myasthenia gravis notes increased muscle
strength when treated with acetylcholinesterase inhibitors. The basis of
this improvement is increased
a. Amount of acetylcholine released from motor neurons
b. Formation of acetylcholine vesicles
c. Levels of acetylcholine at muscle end plate
d. Number of acetylcholine receptors at muscle end plate
e. Opening of voltage gated calcium channels at presynaptic terminal

12. 11. The mechanism of action of diisopropyl fluorophosphate is
a. Stimulation of muscle fiber by acetylcholine like action
b. Stimulation of neuromuscular junction by inactivation of
acetylcholinesterase
c. Blockage of nerve impulse transmission at neuromuscular junction
d. Destruction of acetylcholine receptors
e. Destruction of acetylcholine vesicles

13. 12.Which of the following is a characteristic of neuromuscular junction?
a. They are examples of electrical synapse
b. They are specialized synapse between motor neuron and muscle
fibers
c. They are specialized synapse between sensory neuron and muscle
fibers
d. They involve release of dopamine as primary neurotransmitter
e. They transmit signals between neurons in the brain

14. 13. Which of the following is a neuromuscular junction blocker drug?
a. Carbachol
b. Curariform
c. Methacholine
d. Neostigmine
e. Physostigmine

15. 14. The action potential in the motor neurons triggers the release of
acetylcholine by which effect on axon terminal:
a. Accommodation
b. Depolarization
c. Hyperpolarization
d. Inhibition
e. Repolarization

16. 15.The autoimmune attack in myasthenia gravis leads to which one of
the followings?
a. Destruction of acetylcholine receptors at the neuromuscular junction
b. Impaired synthesis of acetylcholine in motor neurons
c. Impaired synthesis of acetylcholinesterase
d. Increased release of acetylcholine from motor neurons
e. Overactivation of acetylcholinesterase