Introduction
Irritability (sensitivity) – is the ability to detect and respond to changes in the environment.
Stimulus- is changes in the environment (variation in conditions which can produce a change in activity of part or the whole organism).
Response –is the change in activity by the organism.
Receptor – body part that receive stimuli.
Effector – body part that bring about response.
Co-ordination – the linking of all activities that takes place from detection of a stimulus to the response by the organism.
In order for sensitivity and response to be effected there must be
- receptors to receive the stimuli,
- coordinator to integrate information received,
- transmission systems to conduct the stimuli
- effectors to respond to the stimuli.
Animals, unlike plants, have two different but related systems of co-ordination, the nervous system and the endocrine system.