Question

Compare the following.
A. Central Neural System (CNS) and Peripheral Neural System (PNS)
B. Resting potential and action potential
C. Choroid and retina

Answer 1

The nervous system is composed of two major parts such as Central Nervous System (CNS) and Peripheral Nervous System (PNS). It thus represents the commanding centre of the body.

Complete answer:
(a) CENTRAL NEURAL SYSTEM (CNS) VS PERIPHERAL NEURAL SYSTEM (PNS)
The Central nervous system (CNS) acts as the most important coordinating centre of the body which contains the brain and spinal cord. Each part of the system plays a significant role in communicating the information throughout the body.
The Peripheral nervous system (PNS) consists of a vast network of spinal and cranial nerves which are interlinked to the brain and spinal cord of Central Nervous system (CNS) along with the different parts of the body. It performs the role of allowing the brain and spinal cord to send and receive information throughout the other areas of the body.
The primary function of CNS and PNS is to serve as a relation between the brain, spinal cord and the rest of the body which includes the body's muscle glands, and sense receptors.
(b) RESTING POTENTIAL VS ACTION POTENTIAL
Resting potential is concerned with what happens when a neuron is at rest. It is the electrical potential difference across the nerve fibre/ plasma membrane when it does not conduct any nerve impulse or stimulus. The cell membrane is more permeable to Potassium (K+) ions than to Sodium (Na+) ions.
Action potential takes place when a neuron sends information away from the cell membrane. It is the electrical potential difference across nerve fibre/ plasma membranes when stimulus is applied or conducts nerve impulse at any site. The cell membrane is more permeable to Sodium (Na+) ions than to Potassium (K+) ions.
(c) CHOROID VS RETIN
Choroid is the mid vascular layer of the eye which contains numerous blood vessels. The presence of such blood vessels provides nutrients and oxygen to the retina and other tissues.
Retina is found in the innermost thin layer of the nervous coat of the eyeball. It includes photoreceptor cells, rods and cones that are associated with twilight and colour vision respectively. It also converts the light into neural signals and then sends it to the brain.

Note: The nervous system performs three primary functions such as sensory input (to gather information from the body), integration of data (occurs only in the brain) and motor output (impulses are conducted from brain and spinal cord after processing the information).