Types of Coordination

The tissues and organs in the bodies of multicellular organisms do not work independently of each other. They work together performing their many tasks as the needs of the whole body. This means that these activities are coordinated. Coordination also enables the organism to respond to happenings in the world around it.


When we are writing something, our hands and fingers work in collaboration with our muscles, eyes, thoughts etc. and then very intricate movements result.

One familiar example of coordination is the way in which muscles work together during movement. When a player runs to catch a ball, he uses hundreds of muscles to move his arms, legs and back. His nervous system uses information from his sense organs and coordinates these muscles. Due to this coordination, the muscles contract in the correct sequence, power and length of time. But that is not all. Such activities involve many other kinds of coordination. For example; breathing and heartbeat rates are increased, blood pressure is adjusted, and extra heat is removed fast from the body.

How does it happen?

Life activities are controlled and coordinated i.e. body works as one unit, in which its different organs and systems cooperate and work in harmony with each other.

Types of Coordination

There are two types of coordination in organisms:

i. Nervous coordination brought about by nervous system.

ii. Chemical coordination brought about by endocrine system.

Coordination also takes place in unicellular organisms. The response to stimuli is brought about through chemicals.

Animals have both the nervous and chemical coordination systems in their bodies while plants and other organisms have only chemical coordination.

Coordinated Action

A coordinated action has five components;

    1. Stimulus
    2. Receptor
    3. Coordinator
    4. Effector
    5. Response

1- Stimuli

What happens when we touch a snail? We might have seen the flowers of sunflower plant moving towards the sun. What could be the reason for all this? Touch, light etc. are factors that can bring about certain responses in living organisms. These factors are called stimuli. We can define a stimulus as any change in environment (external and internal), which can provoke a response in organism. More examples of stimuli are heat, cold, pressure, sound waves, presence of chemicals, microbial infections etc.

2- Receptors

Stimuli are detected by special organs, tissues or cells of body. For example sound waves are detected by ears, light is detected by eyes, chemicals in air are detected by nose and so on. The organs, tissues or cells which are specifically built to detect particular type of stimuli are called receptors.

3- Coordinators

These are the organs that receive information from receptors and send messages to particular organs for proper action. In nervous coordination, brain and spinal cord are coordinators. They receive information and send messages through neurons in the form of nerve impulses. On the other hand, in chemical coordination, various endocrine glands play the role of coordinators. They receive information in the form of various chemicals and send messages by secreting particular hormones in blood.

4- Effectors

These are the parts of body which receive messages from coordinators and produce particular responses. In nervous coordination, neurons carry messages from coordinators (brain and spinal cord) to muscles and glands, which act as effectors. In chemical coordination, particular hormones carry messages from coordinators (endocrine glands) to particular target tissues, which act as effectors. For some hormones, nephrons act as effectors. Similarly, bones and liver act as effectors for many hormones.

5- Response

On receiving the message from coordinators, the effector performs action. This action is called response. For example, pulling our hand away from something very hot and the movement of the flower of sunflower towards light are responses. Usually, nervous coordination produces immediate but short-living responses while chemical coordination produces slow but long-living responses.

Nervous and chemical coordination
Nervous and chemical coordination

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