CNS acts as a control Centre of the whole nervous system.
It contains brain and spinal cord.
Brain
Human brain is enclosed in a bony skull called cranium. It divided into following parts.
1. Forebrain
It is the largest part of the brain. It consists of three main parts
I. Cerebrum
II. Thalamus
III. Hypothalamus
Cerebrum is the topmost and the largest part of the brain.
It controls many actions like thinking, feelings, emotions, seeing, hearing, perceptions, memory, speech, decision making, etc.
Inside cerebrum there is a small structure called thalamus. It controls many sensory functions.
Hypothalamus lies at the base of thalamus. It controls body temperature, hunger and thirst.
2. Midbrain
It is a small part of the brain that is present below cerebrum. It receives information from sense organs and sends messages to concerned part.
3. Hindbrain
It consists of three main parts
I. Cerebellum
II. Pons
III. Medulla oblongata
Cerebellum lies under the back part of cerebrum. It acts as a controller for maintaining balance and accurate movements.
Pons is oval structure and present beneath the midbrain.
It controls many function like sleeping, swallowing, equilibrium and taste etc.
Medulla oblongata is connected with the spinal cord. It controls heartbeat, breathing and digestion etc. it also keeps working when rest of brain goes to sleep.
4. Spinal Cord
It is an extension of medulla oblongata. It runs backwards inside the backbone up to its lower end.
It creates a link between brain and different body parts. It also controls some reflex actions and some other involuntary actions.