Homeostasis 1 Flashcards
Overview, The Nervous system, The eye, Thermoregulation.
Homeostasis
The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.
Why do the internal conditions of your body need to be regulated?
To maintain the optimum conditions for cells to function properly and for enzyme action.
What does homeostasis include the control of in the human body?
-Blood glucose concentration
-Body temperature
-Water levels
What do automatic control systems do?
Regulate your internal environment.
What can automatic control systems involve?
-Nervous responses
-Chemical responses
What do all control systems include?
-Receptor cells
-Coordination centres
-Effectors
Receptors
Cells which detect stimuli
Stimuli
Changes in the (internal or external) environment
Give examples of coordination centres in the human body.
-Brain
-Spinal Chord
-Pancreas
What do coordination centres do?
Interpret a change and organise a response.
What two things can effectors be?
-Muscles
-Glands
What do effectors do?
Bring about responses which restore optimum levels.
Examples of negative feedback
-The control of blood glucose concentration
-The control of body temperature
In what order are signals passed along the control system?
receptor ➔ coordination centre ➔ effector
What do muscles do when stimulated?
Contract
What do glands do when stimulated?
Secrete hormones
Why does the endocrine system act more generally across the body?
It involves releasing hormones into the blood stream which means they spread throughout the entire body.
Why is the nervous system much faster acting than the endocrine system?
It relies on electrical impulses that can travel very quickly.
Homeostasis relies on a system of what?
negative feedback
Negative feedback
A mechanism which your automatic control systems use to keep your internal environment stable.
How does negative feedback work?
Any change in a system causes an action that reverses that change.
Whenever the levels of something get too high they’re brought back down, and whenever the levels of something get too low, they’re brought back up.
What does the nervous system enable humans to do?
React with their surroundings and coordinate their behaviour.
What is the CNS?
Central nervous system.
What is the central nervous system made of in vertebrates? (animals with backbones)
-Brain
-Spinal chord