Excretion
- Created by: emews
- Created on: 02-11-17 17:26
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- Excretion
- Excretion is the removal of:
- Toxic materials
- Waste products of metabolism
- excess substances from organisms
- Excretion is not the same as egestion
- Plants
- Plants need to excrete excess carbon dioxide and oxygen
- Oxygen is a waste product of photosynthesis
- Human excretory organs
- sweat glands in the skin produce sweat. The water in sweat cools body down
- Excess carbon dioxide and some water vapour are exhaled
- The kidneys are organs of the urinary system
- urinary system
- blood is brought to the kidney in the renal artery. The kidneys filter the blood and then reabsorb useful materials such as glucose.
- Urine is taken from the kidneys to the bladder by the ureters.
- urine contains water, urea and salts
- Urea is produced in the liver when excess amino acids are broken down.
- the kidney
- The inner part of the kidney is called the medulla and the outer part is the cortex
- blood is filtered at high pressure to remove glucose, water, salts and urea
- The nephron
- Urine is produced in microscopic structures in the kidney called nephrons.
- The blood is put under high pressure
- ultrafiltration of the blood happens, in which water, ions, glucose and other small molecules pass into the tubule.
- collecting duct is responsible for:
- the selective reabsorption of water
- Sending urine to the ureter
- ADH
- The water content of the blood is controlled by a hormone called ADH.
- Different amounts of ADH are realeased into the bloodstream according to the concentration of the blood plasma.
- The diagrams show what happens when there is either too little or too much water in the blood.
- Excretion is the removal of:
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