COMMUNICATION
HOMEOSTASIS
___
INTRODUCTION
To increase survival chances, organisms need to respond to changes in their internal and
external environment (stimuli) and coordinate different functions of specialised cells, organs
and organ systems to operate efficiently.
Cell signalling (nervous system and endocrine system)
1 cell releases a chemical that has an effect on the target cell which responds to the signal
Cell can transfer signals :
- locally btw neurons at synapses (with neurotransmitters)
- Distantly : hormones travel in the bloodstream
Homeostasis
Maintains a constant internal environment for optimal conditions for enzyme action and all cell
functions, despite fluctuations in the external environment.
1. negative feedback
Reverses change detected
HOMEOSTASIS
___
INTRODUCTION
To increase survival chances, organisms need to respond to changes in their internal and
external environment (stimuli) and coordinate different functions of specialised cells, organs
and organ systems to operate efficiently.
Cell signalling (nervous system and endocrine system)
1 cell releases a chemical that has an effect on the target cell which responds to the signal
Cell can transfer signals :
- locally btw neurons at synapses (with neurotransmitters)
- Distantly : hormones travel in the bloodstream
Homeostasis
Maintains a constant internal environment for optimal conditions for enzyme action and all cell
functions, despite fluctuations in the external environment.
1. negative feedback
Reverses change detected
