4.5.1 - Principles of Homeostasis Flashcards
Students should be able to explain that homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.
What is homeostasis?
Homeostasis is the regulation of conditions in the body to maintain a stable internal environment, in response to both internal and external conditions.
What internal conditions are controlled by homeostasis?
- body temperature
- water content of body
- blood glucose concentration
What does our body use to maintain the internal environment?
It uses an automatic control system.
What are the three main components of automatic control systems?
- receptors
- coordination centres
- effectors
What do receptors do?
Detect stimuli (change in environment), e.g. rise in temperature
What do coordination centres do?
Receive & process info (the change) from receptors, send signals & coordinate response of body. (brain, spinal cord, pancreas)
What do the effectors do?
Muscles or glands that carry out responses to stimuli and restore conditions in the body to optimum levels.
Which two systems send signals between the automatic control systems?
- nervous system
- endocrine system
What does the nervous system do?
Sends out very fast & precise electrical impulses through nerves, and responds quickly.
What does the endocrine system do?
Relies on hormones. It is slower, longer lasting, & more generalised than nervous system.
What is negative feedback?
When there is a change, this stimulus is detected and the body reverses (counteracts) the change and returns conditions to the optimum. E.g. if glucose levels are too high, it returns it back to normal. It is a continuous cycle.
What does homeostasis maintain optimal conditions for?
Enzyme action and cell functions.
