| what is meant by excretion? | the process of ridding the body of waste products |
| what is the name given to the process of excreting un-digestable food? | egestion |
| name three waste products of metabolism | carbon dioxide, water, urea |
| what are the two functions of the kidneys? | to get rid of waste (urea) and to regulate levels of other substances (water and ions) |
| what is deamination? | the process of forming urea in the liver from excess amino acids |
| what happens if you have too high or low levels of ions? | it can damage your cells |
| what happens if you have too high or low levels of water | - too high levels can cause your cells to swell and burst
- too low levels can cause your cells to lose water and shrink |
| what are three ways we lose water? | via the skin (sweating) via the lungs (breathing) and via the kidneys (urinating) |
| what is the function of tubules? | to absorb small molecules and reabsorb useful molecules back into the bloodstream |
| what are examples of things that tubules will reabsorb into the bloodstream? | glucose (always), water and ions (sometimes) |
| what will tubules never reabsorb? | urea |
| what is the process that the tubules carry out called? | selective reabsorbtion |
| what is the function of the hypothalmus? | to detect water concentration. |
| what does the hypothalmus do if water levels are too low, and what is the result of this action? | the hypothalmus sends a signal to the pituitary gland to release a hormone called ADH.
ADH will encourage water to be reabsorbed in the kidneys
less urine will be produced |
| what does the hypothalmus do if water levels in the body are too high? | no signals will be sent to the pituitary gland
less ADH will be produced
less water will be absorbed by the kidneys
more urine will be produced |
| what is the process of water regulation an example of? | a negative feedback loop |
