Unmyelinated neurons:
1. are surrounded by Schwann cells and a discontinuous myelin sheath
2. are surrounded by Schwann cells that do not secrete a myelin sheath
3. are not surrounded by Schwann cells or a myelin sheath
4. are surrounded by a discontinuous myelin sheath but no Schwann cells

The re-establishment of the resting membrane potential after depolarization is primarily due to:

The resting axonal membrane is:

Most sensory receptors function by producing depolarising potentials. Which of the following function by hyperpolarization rather than depolarization?
1. proprioceptors
2. nociceptors
3. olfactory receptors
4. rods and cones

Each time the sodium-potassium pump works, it transports:
1. three sodium ions to the outside and brings two potassium ions to the inside
2. two sodium ions to the outside and brings three potassium ions to the inside
3. three potassium ions to the outside and brings two sodium ions to the inside
4. two potassium ions to the outside and brings two potassium ions to the inside

The autonomic neural system relays impulse from the CNS to:

In the human eye, there are three types of cones – red blue and green. When these cones are stimulated equally, a sensation for which of the following colors would be produced?

Most of the neurons in the cerebral cortex are:

When a neuron is resting, the axonal membrane is comparatively:
1. More permeable to sodium ions than for potassium ions
2. More permeable to potassium ions than for sodium ions
3. Equally permeable for potassium and sodium ions
4. Impermeable to sodium and potassium ions