Reception, Response and Coordination in Animals

Animals show irritability i.e. react to changes on their environment. These changes which are known as stimuli, are detected by receptors which are either sensory cells found in various parts of their bodies or sense organs like eyes, ears and tongue.

The stimuli are transmitted as impulses along nerves and a response is brought about by an effector.

Unlike plants, animals have two different but related systems of co-ordination. These are;

A. Nervous system

B. Endocrine (hormone) system

• The Nervous system

It is made up of nerve cells (nerves).

The nerves link up the receptors and the effectors enabling the animal to respond appropriately to stimuli.

The mammalian nervous system is composed of two parts:

(a) Central nervous system (CNS)

(b) Peripheral nervous system (PNS)

Central Nervous System (CNS)

It is made up of the brain and spinal cord.

It receives and integrates impulses from the receptors and then relays them to the effector organs.

It is the centre of co-ordination.

Peripheral nervous system (PNS)

It is made up of sensory nerves and motor nerves.

Sensory nerves transmit impulses from the receptors in sensory organs to the CNS.

Motor nerves transmit impulses from CNS to effector organs.