The stapes sends its vibrations to 
1. Incus 
2. Round window
3. Tympanic membrane
4. Oval window

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.

Above the rows of hair cells of Organ of Corti, there is a thin elastic membrane called:
1. Reissner's membrane
2. Basilar membrane
3. Tectorial membrane
4. Tympanic membrane

The vasomotor center that controls the diameter of blood vessels is located in the

1. medulla oblongata

2. pons

3. cerebrum

4. cerebellum

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

Receptor sites for neurotransmitters are present on
1. membrances of synaptic vesicles
2. pre-synaptic membrane
3. tips of axons
4. post-synaptic membrane

Good vision depends on adequate intake of carotene rich food.

Select the best option from the following statements.

I. Vitamin-A derivatives are formed from carotene.
II. The photopigments are embedded in the membrane discs of the inner segment.
III. Retinal is a derivative of vitamin-A.
IV. Retinal is a light absorbing part of all the visual photopigments.

(1) (I) and (II)

(2) (I), (III) and (IV)

(3) (I) and (III)

(4) (II), (III) and (IV)

Myelin sheath is produced by
(1) Schwann cells and Oligodendrocytes

(2) Astrocytes and Schwann cells

(3) Oligodendrocytes and Osteoclasts

(4) Osteoclasts and Astrocytes