The sensory neuron enters the spinal cord through:

1.	The dorsal root of the spinal nerve
2.	The ventral root of the spinal nerve
3.	Either dorsal or ventral root depending on the point of origin
4.	Both dorsal and ventral roots of the spinal nerves

The depolarization of the axonal membrane is due to:

1. Influx of sodium ions

2. Efflux of sodium ions

3. Influx of potassium ions

4. Efflux of the potassium ions

Immediately after an action potential has peaked, which cellular gates open?

1. Sodium
2. Chloride
3. Calcium
4. Potassium

In a chemical synapse, when an impulse arrives at the axon terminal, it:
1. leads to the opening of the calcium channels at the post-synaptic membrane.
2. Stimulates the fusion of synaptic vesicles towards the pre-synaptic membrane.
3. causes the binding of the neurotransmitter of its receptors on the post-synaptic neuron.
4. activates the opening of the potassium channels in the axon terminal.

Consider the following statements:

I. Somatic neural system relays impulses from CNS to skeletal muscles.

II. Autonomic neural system transmits impulses from CNS to involuntary organs and smooth muscles.

III. Unmyelinated nerve fibres are commonly found in spinal and cranial nerves.

Which of the above statements are true?

1. I and II only

2. I and III only

3. II and III only

4. I, II, and III

Consider the following statements:

Which of the above statements are true?

1. I and II only

2. I and III only

3. II and III only

4. I, II and III

Consider the following statements:

I. Acetylcholine is released at the electric synapse.

II. Electric synapses are faster.

III. It is more difficult to regulate an electric synapse with respect to a chemical synapse.

Which of the above statements are true?

1. I and II only

2. I and III only

3. II and III only

4. I, II, and III

During the propagation of a nerve impulse, the action potential results from the movement of

1. K⁺ ions from extracelular fluid to intracellular fluid

2. Na⁺ ions from intracellular fluid to extracellular fluid

3. K⁺ ions from intracellular fluid to extracellular fluid

4. Na⁺ ions from extracellular fluid to intracellular fluid

Which of the following minerals reduces the excitability of nerves and muscles?

1. Potassium

2. Sodium

3. Magnesium

4. Manganese