Nervous System Guidelines | PART 2 | Biology Class 12 | NEET | MDCAT | Lets Crack MDCAT

Nervous System Guidelines | PART 2 | Biology Class 12 | NEET | MDCAT | Lets Crack MDCAT
One of the most complex organ system to ever evolve, the human nervous system consists of two parts, namely:
Central Nervous System (consists of the brain and spinal cord)
Peripheral Nervous System (includes all the nerves of the body)
Central Nervous System
Central Nervous System (CNS) is often called the central processing unit of the body. It consists of the brain and the spinal cord.
Brain
The brain is one of the important, largest and central organ of the human nervous system. It is the control unit of the nervous system, which helps us in discovering new things, remembering and understanding, making decisions, and a lot more. It is enclosed within the skull, which provides frontal, lateral and dorsal protection. The human brain is composed of three major parts:
Forebrain: The anterior part of the brain, consists of Cerebrum, Hypothalamus and Thalamus.
Midbrain: The smaller and central part of the brainstem, consists of Tectum and Tegmentum.
Hindbrain: The central region of the brain, composed of Cerebellum, Medulla and Pons.
Also read: Human Brain
Spinal Cord
The spinal cord is a cylindrical bundle of nerve fibers and associated tissues enclosed within the spine and connect all parts of the body to the brain. It begins in continuation with the medulla and extends downwards. It is enclosed in a bony cage called vertebral column and surrounded by membranes called meninges. The spinal cord is concerned with spinal reflex actions and the conduction of nerve impulses to and from the brain.
Peripheral Nervous System
Peripheral Nervous System (PNS) is the lateral part of the nervous system that develops from the central nervous system which connects different parts of the body with the CNS. We carry out both voluntary and involuntary actions with the help of peripheral nerves.
Also refer: Peripheral Nervous System
PNS includes two types of nerve fibers:
Afferent nerve fibers - These are responsible for transmitting messages from tissues and organs to the CNS.
Efferent nerve-fibers - These are responsible for conveying messages from CNS to the corresponding peripheral organ.
Classification of the peripheral nervous system:
Somatic neural system (SNS): It is the neural system that controls the voluntary actions in the body by transmitting impulses from CNS to skeletal muscle cells. It consists of the somatic nerves.
Autonomic neural system (ANS): The autonomic neural system is involved in involuntary actions like regulation of physiological functions (digestion, respiration, salivation, etc.). It is a self-regulating system which conveys the impulses from the CNS to the smooth muscles and involuntary organs (heart, bladder and pupil). The autonomic neural system can be further divided into:
Sympathetic nervous system
Parasympathetic nervous system
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