A million nephrons in one kidney

• Resources Structure
• Key Stage 4
• Biology
• IX. Homeostasis
• 43. Regulation of the amount and composition of systemic fluids by the kidneys

• Exam Specifications
• Key Stage 4
• AQA GCSE Science A (4461) Biology
• I. Biology 1a – Human Biology
• 1. How do human bodies respond to changes inside them and to their environment?
• Internal conditions which are controlled include: - the water content of the body - the ion content of the body - temperature - blood sugar levels
• AQA GCSE Additional Science (4463) Biology
• II. Biology 2
• 7. How do our bodies keep internal conditions constant?
• Waste products which have to be removed from the body include: - carbon dioxide produced by respiration, - urea produced in the liver by the breakdown of excess amino acids.
• Internal conditions which are controlled include the water content of the body, the ion content of the body, temperature and blood sugar levels.
• If the water or ion content of the body is wrong, too much water may move into or out of the cells and damage them. Water and ions enter the body when we eat and drink.
• Sweating helps to cool the body. More water is lost when it is hot, and more water has to be taken as drink or in food to balance this loss.
• AQA GCSE Biology (4411)
• III.Biology 3
• 4. How do exchanges in the kidney help us to maintain the internal environment in mammals and how has biology helped us to treat kidney disease?
• to evaluate the advantages and disadvantages of treating kidney failure by dialysis or kidney transplant.
• A healthy kidney produces urine by: - first filtering the blood - reabsorbing all the sugar - reabsorbing the dissolved ions needed by the body - reabsorbing as much water as the body needs - releasing urea, excess ions and water as urine.
• Sugar and dissolved ions may be actively absorbed against a concentration gradient.
• People who suffer from kidney failure may be treated either by using a kidney dialysis machine or by having a healthy kidney transplanted.
• Treatment by dialysis restores the concentrations of dissolved substances in the blood to normal levels. The dialysis fluid contains the same concentration of useful substances as the blood.
• A kidney transplant enables a diseased kidney to be replaced with a healthy one from a donor. However, the donor kidney may be rejected by the immune system unless precautions are taken.
• To prevent rejection of the transplanted kidney: - a donor kidney with a ‘tissue-type’ similar to that of the recipient is used - the recipient is treated with drugs that suppress the immune system.
• II. Biology 1
• 1.How do human bodies respond to changes inside them and to their environment?
• Internal conditions which are controlled include: - the water content of the body, - the ion content of the body, - temperature, - blood sugar levels.
• III.Biology 2
• 7. How do our bodies keep internal conditions constant?
• If the water or ion content of the body is wrong, too much water may move into or out of the cells and damage them. Water and ions enter the body when we eat and drink.
• Sweating helps to cool the body. More water is lost when it is hot, and more water has to be taken as drink or in food to balance this loss.
• Waste products which have to be removed from the body include: - carbon dioxide produced by respiration, - urea produced in the liver by the breakdown of excess amino acids.
• Internal conditions which are controlled include the water content of the body, the ion content of the body, temperature and blood sugar levels.

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