Homeostasis Flashcards
What is homeostasis
The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external change
Internal conditions
- Blood glucose concentration
- Water levels
- Body temperature
Control systems in the body:
- Cells called receptors, which detect changes in the environment (stimuli)
- Coordination centres (brain, spinal cord, pancreas) receive and process information from receptors.
- Effectors, muscles or glands which bring about responses that restore optimum levels.
How does the body react to being too hot
- Blood vessels dilate to increase blood flow which releasees heat.
- Hair lies flat to reduce the layer of air insulation.
- More sweat is produced for cooling by evaporation.
How does the body react to being too cold
- Blood vessels constrict to reduce blood flow so less heat is lost.
- Hair stands up to increase the area of air insulation.
- Little to no sweat is produced.
How does the body react when blood glucose levels are too low
- Pancreas detects low glucose level.
- Pancreas releases glucagon into the blood
- Glucagon converts the glycogen in the liver back to glucose, which is released into the blood to restore the glucose levels.
How does the body react when blood glucose levels are too high.
- Pancreas detects high level of blood glucose.
- Pancreas releases more insulin into the blood.
- Cells absorb more glucose.
- Liver converts glucose into glycogen.
- Glucose level is restored.
How does the body react to low levels of water in the blood stream
- Hypothalamus detects the level of water in the blood.
- ADH hormone is produced.
What is vasoconstriction
When blood vessels constrict on the surface of the skin to conserve heat.
What is vasodilation
When blood vessels dilate on the surface of the skin to reduce temperature.
What is thermoregulation
The control of body temperature
