Co-ordination and Response in Humans Flashcards
Define homeostasis
The regulation of the internal conditions of a cell or an organism
Explain why homeostasis is necessary
To maintain the right conditions for an organisms enzymes and all cell functions to function optimally
so that the necessary reactions can happen and the organism can live
Name two examples of homeostasis in humans
- Control of water content
- Control of body temperature
What is the optimum core body temperature for humans?
37 degrees celcius
Explain why maintaining core body temperature is important
A temperature change of more thean 2 degrees would stop essential enzymes from functioning properly
What happens to enzymes when body temp gets too high/low
When it gets too high, enzymes denature. When it gets too low, enzyme activity decreases
Explain 3 cooling mechanisms in humans
Vasodilation of skin capillaries- this means arterioles relax, relaxing capilleries and supplying them with a greater amount of blood which then loses heat to the environment due to radiation
Sweating - Sweat is secreted through sweat glands, cooling the skin by evaporation which uses heat energy from the body to convert liquid water into vapour
Flattening of hairs- Hair erector muscles relax, causing hairs to lie flat which stops them from making an insulating layer trapping warm air and allowing heat to leave by radiation
Explain 3 heating mechanisms in humans
Vasoconstriction- muscles in arteriole walls contract, causing arterioles to contrict and decreasing blood supply through the capilleries. This only stops heat loss, though, and is not necessarily a heating mechanism
Shivering- shivering is a reflex action where muscles rapidly contract and relax repeatedly, generating sufficient heat energy to warm the blood and raise core body temp
Erection of hair- Hair erector muscles contract, raising the hair on the skin and forming an insulating layer of hair which traps hot air and stops heat loss by radiation
