Co-ordination Through Nervous System
It is that phenomenon in which different activities of the different organs and the entire organism are regulated in an organized manner. In the nervous system the brain and the spinal act as coordinators
STEPS INVOLVED IN CO-ORDINATION
(1) The passing of information in the form of external or internal stimuli to the co-ordination.
(2) Interpreting the information in co-ordination and conveying the relevant orders to the effects.
(3) The responding of the effects in accordance with the order received from the Coordinator.
If we want to have co-ordination through the nervous system then we should try to know how animals receive stimuli and respond to them.
In the human body, three types of structure are present which concern the stimuli and responses. These structures are known as:
These are the organs that receive external stimuli and transmit them to the brain or spinal cord.
A neuron is a single nerve cell that has a cell body and a nucleus.
These are the organs that give a response on receiving orders from the nervous system. Effectors exit in the form of glands and muscles.
TYPES OF NEURON
There are two types of neurons.
1. SENSORY NEURON
These are the neurons that carry impulses to the central nervous system (brain and spinal cord).
2. MOTOR NEURONS
These neurons carry impulses from the central nervous system to the effectors.
STRUCTURE OF NEURON
A neuron is a single cell that has a cell body having a nucleus. At one end of the cell there exist many fine branches known as dendrites. At the other end of the cell, the body is prolonged into a long fiber known as Axon.
Generally, the axon has branches at its end. Some axons is as long as more than one meter. Many nerve fibers join together to form a nerve.
3. NERVE IMPULSE
All sensory organs send information to the brain in the form of an electric impulse. These dendrites of a neuron and pass through nerve fibers on to the next neuron. The impulse that reaches the brain through nerves and the spinal cord is interpreted by the brain cells. After interpretation of impulses, the brain sends a back impulse through a different set of nerves to the organs which carry out or respond to the instruction of the brain.
Human actions are of two types:
- Voluntary Action
- Involuntary Action.
The actions which involve the thinking part of the brain are called voluntary actions. Walking, Talking, Singing, and playing is examples of voluntary actions.
Such action which does not involve any thinking part of the brain is called involuntary Actions. Body actions such as hear best respiration, digestion, and excretion are examples of involuntary actions.
This action takes place without involving the brain. This is a kind of involving action which is called reflex action. For the performance of Reflex Action the parts are involved given below:
- Receptor (any part of the body).
- Sensory Nerves.
- Motor Nerves.
- Brain or Spinal cord.
- Effectors (Muscles or Glands).
When a needle is accidentally struck into your finger you pull away from your hand immediately although the prick is felt quite late.
The events which occur in reflex action are given below in serial order.
- First of all sensory neurons are stimulated by the receptors of the hand.
- Sensory neurons send an impulse to the associated neurons lying in the spinal cord of the central nervous system.
- Afterward, the impulse is conveyed by associative neurons to the motor hand.
- At this stage, the impulse is carried by motor neurons to the muscles of the hand.
- Finally the muscles of the hand react to motor impulse due to which the hand-pulled away immediately from the needle.
(1) Watering of mouth on smelling or seeing good food.
(2) Blinking of eyes when are exposed to strong light.
(3) Erection of hairs due to terror.
(4) Increasing of a heartbeat on hearing some loud sound or bad news.
(5) Shivering due to cold.