Kidney Functions and Malfunctions

What Kidney Functions and Malfunctions covers

Kidney Functions and Malfunctions is examined in all three written papers — the specification states that Components 01, 02 and 03 can each assess content from any of the five modules, so nothing is confined to one paper. It covers excretion and the gross structure of the kidney, the nephron: ultrafiltration and selective reabsorption, investigating the composition of urine, plasma and filtrate, osmoregulation and the action of ADH, the kidney as an endocrine gland and kidney failure and dialysis, transplantation and the future of transplant surgery.

The 6 subtopics

Each one has its own page.

• Excretion and the gross structure of the kidneyRecall questions on excretion, deamination in the liver and its products, why ammonia becomes urea, the cortex, medulla, renal pyramids and pelvis, the renal artery and vein, the path of urine, renal blood flow, and dissecting a kidney safely.Open →
• The nephron: ultrafiltration and selective reabsorptionRecall questions on the parts of the nephron, ultrafiltration through endothelium, basement membrane and podocytes, what glomerular filtrate contains, reabsorption of glucose by co-transport in the proximal convoluted tubule, the loop of Henle and collecting duct, and the distal convoluted tubule.Open →
• Investigating the composition of urine, plasma and filtrateRecall questions on why mock samples are used, testing for glucose, protein and urea, what filtrate should not contain, artery and vein comparisons, and colorimetric measurement.Open →
• Osmoregulation and the action of ADHRecall questions on where the osmoreceptors sit, the route ADH takes, cyclic AMP and aquaporins in the collecting duct, and the feedback response to drinking heavily or sweating.Open →
• The kidney as an endocrine gland and kidney failureRecall questions on the hormone that drives erythrocyte production, renin and angiotensin II raising blood pressure, the causes of kidney damage, albumin in urine, and estimating filtration rate.Open →
• Dialysis, transplantation and the future of transplant surgeryRecall questions on the composition of dialysis fluid and countercurrent flow, haemodialysis and peritoneal dialysis compared, kidney transplants, tissue matching and immunosuppressants, living donors, and therapeutic cloning, its ethics, reproductive cloning and induced pluripotent stem cells.Open →

What you need to know

Answer each one before you reveal it.

Take Kidney Functions and Malfunctions further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Ureter vs Urethra

  Ureter: the tube that carries urine from the kidney down to the bladder, where it is stored. Urethra: the tube that carries urine from the bladder out of the body.

• Afferent arteriole vs Efferent arteriole

  Afferent arteriole: the wider vessel bringing blood into the glomerulus, delivering more blood than can leave at the same rate. Efferent arteriole: the narrower vessel taking blood away from the glomerulus, whose narrow lumen raises the hydrostatic pressure behind it.

• Renin vs Erythropoietin

  Renin: an enzyme released by the kidney when blood pressure or blood sodium falls, starting the cascade that produces angiotensin II. Erythropoietin: a hormone released by the kidney when the oxygen concentration of the blood falls, which makes the bone marrow produce more red cells.

Questions from this topic

Each one with the model answer underneath.

1. 1

   Define excretion.

   Model answer

   Excretion is the removal from the body of the waste products of metabolism.

2. 2

   Why can the body not simply store surplus amino acids?

   Model answer

   Amino acids contain nitrogen and cannot be stored as protein or converted directly into fat or carbohydrate, so any surplus must have its amino group removed and be excreted.

3. 3

   What is deamination, and in which cells does it take place?

   Model answer

   Deamination is the removal of the amino group from an amino acid, and it takes place in the cells of the liver.

4. 4

   Name the two products formed when an amino acid is deaminated, and state what happens to each.

   Model answer

   Ammonia, which is converted into urea, and a keto acid, which is either respired to release energy or converted into glycogen or fat for storage.

5. 5

   Why is ammonia converted into urea rather than being excreted as it is?

   Model answer

   Ammonia is extremely soluble and highly toxic even at low concentrations, so the liver converts it into urea, which is far less toxic and can be carried safely in the blood until the kidney removes it.

6. 6

   How is urea carried from the liver to the kidney?

   Model answer

   It is carried dissolved in the blood plasma, leaving the liver in the hepatic vein and reaching the kidney through the renal artery.

What is inside Levo

Six ways to work the same material.

Kidney Functions and Malfunctions revision questions

What does Kidney Functions and Malfunctions cover in OCR A-Level Biology B?

6 subtopics: excretion and the gross structure of the kidney, the nephron: ultrafiltration and selective reabsorption, investigating the composition of urine, plasma and filtrate, osmoregulation and the action of adh, the kidney as an endocrine gland and kidney failure and dialysis, transplantation and the future of transplant surgery. Each one has its own page with questions and model answers.

How is Kidney Functions and Malfunctions organised?

By the OCR H422 specification, subtopic by subtopic, so it matches the order you are taught it in.