Homeostasis Flashcards
What is Homeostasis?
The maintenance of a constant internal enviroment e.g. body water content
What does the Hypothalamus in the brain do?
Monitors temperature of the blood
What are the main ways how the body controls temperature?
Sweating
Shivering
Amount of blood flow near the skin (Vasoconstriction and vasodilation)
What happens when skin hairs stand on end?
Traps a layer of air which provides insulation for the conduction of heat (less heat loss)
What happens when less sweat is released?
Less heat loss via evaporation (less heat loss)
What happens when Vasoconstriction occurs?
Capillaries near the surface of the skin get narrower
Less blood flows through capilliaries near surface
Less heat loss through radiation
What happens when skin hairs lie flat?
Insulating layer is not formed (more heat loss)
What happens when more sweat is released?
The sweat evaporates and heat energy is taken away from the skin
What happens when Vasodilation occurs?
Capilliaries near surface of skin get wider
More blood will flow through them
Therefore more heat will be lost through radiation
What is Osmoregulation?
The regulation of water levels within the body
How can water levels be changed in the body?
Adjusting the permeability of the collecting duct in the nephrons (kidney)
What happens when water levels are low?
Hypothalamus tells the pituitry gland to release more ADH
ADH goes into capilliaries near the collecting ducts and binds with receptors on surface of collecting duct cells
This triggers the wall of collecting duct to become more permeable to water
Therefore more water is reabsorbed into the blood
And urine is more concentrated
