Nervous System

A stimulus which exceeds the threshold level is required to generate an action potential.

Intensity and amplitude are related. Our ear perceives some frequencies to be louder than others.

The limbic system is also involved in memory and learning. Choices A and C refer to the reticular formation of the brain. Choice D is performed by the thalamus.

Hypothalamus is the main visceral control centre of body homeostasis. It is the autonomic control centre from which orders flow to lower CNS centres for execution.

Optic disc is where no rods or cones exist as the nerves and blood vessels pass out through the choroid and sclera here.

The tectorial membrane lies over the hair cells of the organ of Corti (which sits on the basilar membrane).

Spinal reflexes do not require processing by the brain. Hence they are not useful for choice C and are present even after brain death.

A neurotransmitter is released from within one neuron and crosses the cleft to bind with the receptor in the membrane of the next cell.

Cerebellum subconsciously provides precise timing and appropriate patterns of learned skilled skeletal muscle contraction for smooth coordinated movements, posture and agility.

The myelin sheath insulates the axon. That is, it prevents ions from crossing the plasma membrane except at the nodes of Ranvier, where the sheath is absent.