“In the multicellular organisms various activities of the body are controlled and regulated by a specific system called as nervous system”
In humans and animals the nervous system is formed by specific types of cells, these cells are called neurons. Each nerve cell consists of nerve cells and nerve fibres. Nerve fibres are of two types Axon and Dendron.
Nervous System in Human:
Nervous system of humans and other vertebrates is divided into two parts-1. Central Nervous System 2. Peripheral nervous system
(1) Central Nervous System: It controls and regulates the whole body organ. It’s like the central processing unit of our body. It includes two parts: Brain and Spinal cord.
–Brain: Brain controls various biological activities of the human body. It is the central organ of human nervous system.
Function of brain: 1)Brain is the center of various sensations such as visual and auditory. 2) It stimulates the behavior for cold, heat, touch and light. 3) It controls the involuntary actions of nervous system and also hunger, thirst, heat, sleep, fatigue, hatred, sexual activities. 4) Control voluntary movements. 5) Control the heart beat and respiratory rate. 6) It is the center of feelings, emotions, intelligence, memory, reasons and will.
–Spinal Cord: It is situated inside the neural canal of the vertebral column. It is surrounded by three layers of connective tissue. In spinal chord the white matter is present outwardly and grey matter inwardly. In between this three layers cerebro spinal fluid is present. Spinal fluid protects the spinal fluid from external shocks.
Function of Spinal Cord: 1) Conducts sensory information from the peripheral nervous system to the brain. 2) Coordinate and regulate the reflex action.
(2) Peripheral Nervous System: Peripheral nervous system contains all the nerves that lies outside the central nervous system. It’s primary function is to connect the central nervous system to the organs, limbs and skins. It allows the brain and spinal cord to recieve and send information to other parts of the body, which allows us to react to stimuli in our environment.