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

1. Potassium

2. Sodium

3. Magnesium

4. Manganese

Node of Ranvier occurs where
(1) nerve is covered with myelin sheath

(2) neurolemma is discontinuous

(3) neurolemma and myelin sheath are discontinuous

(4) myelin sheath is discontinuous

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

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

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. 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

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.

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

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

Neuron cannot perform which of the following functions?

Which of the following does not has brain?