Kidneys

Question 1

Function of Kidneys

Answer 1

• Regulates level of ions, waste products and water in the bloodstream

Question 2

Removing urea

Answer 2

• Filters urea made in liver from deamination, where excess amino acids are converted to fats and carbohydrates for storage

Question 3

Importance of regulating water concentration

Answer 3

• Too high -> cells absorb too much water via osmosis
• Cells will swell up and eventually burst
• Too low -> cells can’t absorb enough water
• Cells will dry out, shrivel and shrink

Question 4

Selective reabsorption

Answer 4

• Kidneys filter blood by absorbing small molecules like water, amino acids, glucose, urea (not proteins/cells)
• Useful products are reabsorbed, like glucose, water, but no urea

Question 5

Regulating low water concentration level in blood

Answer 5

• Low water concentration in blood stream detected by hypothalamus
• Pituitary gland stimulated to release ADH
• Kidney reabsorbs more water
• Less urine produced

Question 6

Regulating high water concentration in blood

Answer 6

• High water concentration in blood detected by hypothalamus
• Stops sending signals to pituitary gland
• Won’t release as much ADH
• Kidneys reabsorb less water
• More urine made

Question 7

Kidney failure

Answer 7

• waste products build up in blood stream
• unable to regulate water and ion levels
• can become sick and die

Question 8

Dialysis machine

Answer 8

• connect patients blood supply to dialysis machine
• blood goes into machine and comes into contact with dialysis fluid
• dialysis fluid contains same concentration of water/ions as healthy blood
• small molecules dissolve across partially permeable membrane due to concentration gradient
• to maintain gradient and prevent from reaching equilibrium, the fluid is regularly changed
• healthy filtered blood goes back into patient

Question 9

Cons of dialysis

Answer 9

• Time-consuming
• Very costly to run
• Risk of blood clots
• Risk of infection
• Has to be done continually for whole life

Question 10

Kidney transplant

Answer 10

• surgical procedure
• kidney taken from recently died person or an alive organ donor

Question 11

Cons of kidney transplant

Answer 11

• kidney may reject, attacked as foreign object by immune system
  -> can be suppressed by medication
• not enough available organs

Question 12

Pro of kidney transplants

Answer 12

• cheaper than dialysis