We start with interaction functions remembering what you studied last year and I guess you have already known
What is interaction ?
All living beings interact with their environment and with other living beings to survive. lnteraction enables living beings to receive and respond to a stimulus.
Stimuli. These are detectable changes in the internal or external environment. They provoke responses. Stimuli can be:
Physical: light, sound, temperature, pressure, etc.
Chemical: the presence or absence of chemical substances
Biotic: changes caused by the presence of other living beings
• Receptors. These are structures which receive stimuli from the external or internal environment. In animals, the receptors are the sense organs.
• Coordination systems. These consist of organs which process information received by the receptors and produce a response.
• Responsive organs, also called effectors. These are structures which produce responses, such as muscles and glands in animals.
Coordination systems work together to process information received from stimuli and to produce appropriate responses. Human being as most animals have two coordination systems: the nervous system and the endocrine system.
• The nervous system regulates the body's activities and responses. lt works by means of specialised cells called neurons which transmit information in the form of nerve impulses.
• The endocrine system regulates and coordinates the body functions by means of chemical substances called hormones.
In animals, stimuli are processed and analysed quickly. Responses are immediate.