Myelin sheath around the axons in the PNS is secreted by:

1.	oligodendrocytes	2.	axons
3.	Schwann cells	4.	ependymal

The resting axonal membrane is impermeable/nearly impermeable to:
I. Sodium ions
II. Potassium ions
III. Negatively charged proteins

Visual reflexes are coordinated by the part of the human brain known as the:
1. cerebellum
2. superior colliculus
3. inferior colliculus
4. cerebral peduncles

The part of the human brain widely regarded as ‘the gate-keeper to consciousness’ is the:
1. vasomotor center
2. corpora quadrigemina
3. diencephalon
4. reticular formation

The auditory tube [also called as the Eustachian tube] functions in equalizing pressure between the middle ear and:

The sensory organ of the otolith organ is called as:

In the given diagram of olfactory membrane, identify the olfactory receptor cell:

When one enters a dark room from a bright area:
1. retinol is converted to rhodopsin and eye sensitivity is decreased
2. rhodopsin is converted to retinol and eye sensitivity is decreased
3. rhodopsin is converted to retinol and eye sensitivity is increased
4. retinol is converted to rhodopsin and eye sensitivity is increased

The amount of light entering the human eye is regulated by: