Question

What are the three main parts of the human nervous system?What are their main functions?

Answer 1

Human nervous system, the system that activates the brain and spinal cord from sensory receptors and conducts impulses back to other parts of the body.

Complete Answer:
The nervous system has three major components:
(I) The brain and the spinal cord make up the Central nervous system.
(II) The peripheral nervous system consists of nerves that branch off the spinal cord and spread to all areas of the body.
(III) Autonomic Nervous System

- The brain plays a central role in regulating most of the body's functions, including consciousness, gestures, sensations, emotions, speech, and memory.
- Some reflex movements can occur through spinal cord pathways without the involvement of brain structures. The spinal cord is attached to a segment of the brain called the brainstem and passes via the spinal canal.
- The cranial nerves are leaving the brainstem.
- Nerve roots leave the spinal cord on both sides of the body.
- The central nervous system (CNS) serves as a recovery centre for the nervous system. It collects information and sends information to the peripheral nervous system.
- The brain collects and interprets the sensory input sent out of the spinal cord. Both the brain and spinal cord are covered by a three-layer coating of connective tissue called meninges.
- The primary function of the peripheral nervous system is to link the brain and spinal cord to the rest of the body and to the external environment.
- This is done by nerves that carry information from sensory receptors in the eyes , ears, skin, nose, and tongue, as well as stretch receptors and nociceptors in muscles , glands, and other internal organs.
- As the CNS absorbs these varied signals and formulates a response, the motor nerves of the - PNS innervate the organs and mediate the contraction or relaxation of the skeletal, smooth or cardiac muscle.
- Thus, the PNS controls internal homeostasis through the autonomic nervous system, modulating respiration, heart rate , blood pressure, digestion, and immune response.
- The peripheral nervous system also regulates the release of secretions from most of the exocrine glands. The PNS innervates the muscles around the sense organs, so it is involved in chewing, swallowing, biting and talking.

Note: The nervous system transmits signals, including internal organs, between the brain and the rest of the body. Thus, the operation of the nervous system regulates the ability to move, breathe, see, remember, and more.