Kidneys

Question 1

What is the function of the renal vein?

Answer 1

takes “cleaned” blood away from kidneys

Question 2

What is the function of the aorta?

Answer 2

main artery supplying oxygenated blood to body

Question 3

What is the function of the renal artery?

Answer 3

brings blood containing “waste” to the kidneys

Question 4

What is the function of the urethra?

Answer 4

carries urine out of the body

Question 5

What is the function of the ureter?

Answer 5

carried urine to the bladder

Question 6

What is the function of the bladder?

Answer 6

muscular sac that stores urine (~700cm³)

Question 7

What is the function of the sphincter muscle?

Answer 7

keeps bladder closed

Question 8

What is the function of the medulla?

Answer 8

lighter middle layer of kidney

Question 9

What is the function of the pelvis (kidney)?

Answer 9

central cavity which collects urine

Question 10

What is the function of the cortex (kidney)?

Answer 10

darker outer layer

Question 11

What is the function of the nephron?

Answer 11

filtration unit (where urine is produced)

Question 12

What is the function of the vena cava?

Answer 12

main vein returning blood to the heart

Question 13

How is waste removed throughout the body?

Answer 13

• Mouth (exhalation) - carbon dioxide and water.
• Skin (sweat) - urea, water and salt.
• Kidneys (urine) - urea, water and salt.

Question 14

Why do we need to remove urea, water, and salt?

Answer 14

• Urea is toxic.
• Excess water has an osmotic effect.
• Excess salt (mineral ions) has an osmotic effect.

Question 15

How does drinking water affect urine production?

Answer 15

• A high water concentration in the blood is bad because it can go into the body cells and make them explode.
• Urine volume increases, so the blood water concentration drops.

Question 16

How does being thirty affect urine production?

Answer 16

• Low water concentration in the blood is bad because water then leaves the cells.
• The urine volume decreases, so the blood water concentration increases.

Question 17

How does eating salty food affect urine production?

Answer 17

• High solute concentration in the blood is bad because water leaves the cells and so they shrink.
• The urine volume decreases, so the blood water concentration increases.

Question 18

Why does the blood become deoxygenated in the PCT?

Answer 18

• Active transport happens in the PCT, and that requires energy. The energy comes from respiration, which requires oxygen. The oxygen is taken from the blood and therefore the blood becomes deoxygenated.

Question 19

What happens when one eats a meal with protein?

Answer 19

• The protein is broken down into amino acids.
• The amino acids go through the ileum and most are taken to the cells.
• The excess amino acids are taken to the liver and become urea.

Question 20

Where does ultrafiltration take place?

Answer 20

• The glomerulus and Bowman’s capsule.

Question 21

What happens during ultrafiltration?

Answer 21

• Uncleaned blood arrives at a high pressure in the glomerulus.
• Small molecules are squeezed through gaps in the wall of the glomerulus and the Bowman’s capsule.
• Large molecules and cells stay in the blood as they are too large to fit through the gaps.
• The result is a filtrate contains small molecules and there is filtered blood containing large molecules.

Question 22

Where does selective reabsorption take place?

Answer 22

• In the proximal convoluted tubule (PCT).

Question 23

What happens during selective reabsorption?

Answer 23

• Useful molecules such as glucose, amino acids and salt are re-absorbed into the bloodstream by active transport.
• Some water moves back into the bloodstream by osmosis.
• Urea stays in the filtrate.
• The result is a filtrate containing urea.

Question 24

Why do th cells lining the PCT have lots of mitochondria?

Answer 24

• Mitochondria have lots of energy (powerhouse of the cell), which is needed for active transport.

Question 25

Why is urea not reabsorbed?

Answer 25

• The carrier proteins are specific to one molecule, and there are no carrier proteins for the urea.

Question 26

Why would there be glucose found in the urine?

Answer 26

• If someone has diabetes, there will be too much glucose in their bloodstream because the insulin in their body is not effective. The PCT doesn't have enough carrier proteins to take away the excess of glucose in the blood - not all the glucose is filtered out.

Question 27

How does being thirsty affect ADH production?

Answer 27

* There is a low water concentration in the blood. * Osmoreceptors in the hypothalamus detect this. * Hypothalamus stimulates pituitary gland to release ADH. * ADH works on the collecting ducts so that they are more permeable to water. * More water is reabsorbed into bloodstream. * Less urine is produced. * Water concentration increases, no more ADH released.

Question 28

How does drinking water affect ADH production?

Answer 28

* High water concentration in blood. * Osmoreceptors in the hypothalamus detect this. * Hypothalamus does not stimulate pituitary gland to release ADH. * Collecting ducts are less permeable to water. * Less water is reabsorbed into bloodstream. * More urine is produced. * Water concentration decreases, ADH is produced once we need it again.

Question 29

How does eating lots of salty food affect ADH production?

Answer 29

* There is a high solute concentration in the blood. * Osmoreceptors in the hypothalamus detect this. * Hypothalamus stimulates pituitary gland to release ADH. * ADH works on the collecting ducts so that they are more permeable to water. * More water is reabsorbed into bloodstream. * Less urine is produced. * Water concentration increases, no more ADH released.

Question 30

Why is kidney failure a threat to life?

Answer 30

* Urea is toxic - must be removed. | * Water and salt affect solute concentration, too much of either could have a bad osmotic effect.

Question 31

How does a dialysis machine work?

Answer 31

* Uncleaned blood taken from a vein enters the dialysis machine and flows between dialysis membranes. * Dialysis fluid contains salt, amino acids, glucose and water in normal blood concentration but no urea. * Urea, excess salt and excess water diffuse from the blood through the selectively permeable membranes into the dialysis fluid. * Dialysis fluid is discarded as waste while cleaned blood leaves the dialysis machine and travels back to the body.

Question 32

Why is the blood taken from a vein rather than an artery into the dialysis machine?

Answer 32

* Veins have a lower pressure than arteries, so the blood flow speed can be controlled. * Veins are closer to the surface and therefore more easily accessed.

Question 33

Why is a warm water bath used for dialysis?

Answer 33

• The blood needs to return to the body at a normal temperature, otherwise the cold blood would kill you.

Question 34

Why is there a blood thinner for dialysis?

Answer 34

• To ensure the blood doesn't clot.

Question 35

What are the disadvantages with kidney transplants?

Answer 35

* Lack of donors. * Risk of rejection - patient has to be on immunosuppressant drugs for the rest of their life. * Anti-rejection drugs mean that the patient will have a worse immune system - higher risk of infection.