Homeostasis = maintenance of a constant internal environment.
Can be affectedby exercise, temperature, blood oxygen levels and salt levels.
Artificial Homeostasis = needed when the body's control systems dont work correctly.
Incubators = help premature babies to survive by controlling temperature and oxygen levels.
Artifical and body systems have ....
- processing centres
Negative Feedback = maintenance of a steady state by reversing the change in conditions.
Antagonistic Effectors = act as opposites to one another.
Hot climates = body temperature too high = sweating
Cold climates = body temperature too low = shivering
Hypothalamus = part of the brain responsible for maintaining homeostasis.
Vasodilation = blood vessels in skin dilate in hot conditions
Vasoconstriction = blood vessels in skin constrict in cold conditions
Heat Stroke = an uncontrolled increase in your body temperature.
Hypothermia = cause when core body temperature falls below 35 degrees celcious
Kidneys = filter your blood to remove urea and to balance levels of water and chemicals
Water level high - kidneys reabsorb less water - large amount of dilute urine
Water level low - kidneys reabsorb more water - small amount of concentrated urine
Amount of water that needs to be reabsorbed into blood plasma depends on ....
- external temperature
- fluid intake
- salt intake
Alcohol causes large amount of dilute urine to be produced
Ecstasy causes small amount of concentrated urine to be produced
Anti Diuretic Hormone = controls concentration of urine. Released into your blood via the pituitary gland.
Alcohol - ADH suppressed - more water leaves the body in urine
Ecstasy - too much ADH produced - too much water remains in the blood
Diffusion = movement of substances from high to low concentration
Substances that move in and out of cells by diffusion include....
- carbon dioxide
- dissolved food
Osmosis = movement of water from high to low concentration
Active Transport = movement of substances against a concentrated gradient (requires energy)
Enzymes = protein molecules that speed up the rate of chemical reactions in cells.
Denatured enzyme = structure of the enzyme is permanently destroyed and stops working.
Active Site = place where the molecule fits into the enzyme
The shape of the active site is affected by...
- pH level