kidneys

Question 1

what was the three main roles of the kidneys?

Answer 1

removal of urea and other waste products and adjustment of salt levels and water content in the blood

Question 2

How did the kidneys carry out the three main roles?

Answer 2

by filtering stuff out of the blood under high-pressure and then re-absorbing the useful things

Question 3

what was the end product and what did it contain?

Answer 3

Urea and excess salts

Question 4

how is the blood cleaned from the heart, kidneys then out the body (5)

Answer 4

Blood from the aorta moves into the renal artery and into the kidney.
The kidney filters the blood and removes some water, urea and excess salts.
• Cleaned blood returns to the heart in the vena cava via renal vein
• The unfiltrated urine leaves the kidneys in the ureters and is stored in the bladder.
Urine is passed out of the body through the urethra.

Question 5

why was regulating water content important?

Answer 5

to keep the body cells functioning normally

Question 6

what would happen if the concentration of the water in the blood was too high?

Answer 6

The water will move into the body cells by osmosis which may swell and burst

Question 7

what happens if the concentration of the water in the blood is too less than

Answer 7

The water will move out of the cells into the blood by osmosis which causes the cells to shrink

Question 8

How do the kidneys help to regulate water content

Answer 8

By controlling how much water is reabsorbed and how much is lost in the urine?

Question 9

Why is removing excess salt important?

Answer 9

as it could mean too much or two little water is drawn into the cells by osmosis

Question 10

what is excretion / excretory system

Answer 10

removal of waste products of metabolisms and regulated water content of blood

Question 11

how is urea removed from the blood and body

Answer 11

By the kidneys and it is excreted from the body in urine

Question 12

What do the nephrons do and about how many are in each kidney

Answer 12

Filter the blood and about a million

Question 13

How is blood filtered in the capillary knot in the nephron?

Answer 13

blood is carried in an arteriole to the capillary not. The arteriole that enters the capillary nuts has a large diameter than the one leaving it which generates high pressure in the capillary knot which causes the liquid part of the blood to be forced out of the capillary knot into the bowman’s capsule. bigger molecules and blood cells can’t pass through the membrane and are not forced out.

Question 14

examples of liquid parts of the blood

Answer 14

Water urea, salt and glucose

Question 15

example of bigger molecules

Answer 15

Protein

Question 16

where does the filter liquid move from the Bowermans capsule?

Answer 16

tubules where all the glucose and some of the water and salts are reabsorbed into the blood capillaries that wrap around it

Question 17

what are useful substances are reabsorbed?

Answer 17

All the glucose is selectively reabsorbed and moved back
into the blood against the concentration gradient
Sufficient salts
Sufficient water, according to the level of hormone ADH

Question 18

what happens to whatever that isn’t reabsorbed?

Answer 18

They form urine and continues out the nephron via collecting duct which passes in the ureter and down to the bladder for storage then urine is excreted through the urethra

Question 19

how did doctors make sure that patient’s blood continues to get filtered even though the kidneys stopped working properly?

Answer 19

Dialysis machines or kidney transplants

Question 20

what is dialysis machine

Answer 20

they contain dialysis fluid which has the same concentration of salt and glucose as blood plasma. The barrier is permeable to things like salt and waste substances but not big molecules like proteins so the waste substances like urea, excess salt and water from the blood move across the membrane into the dialysis fluid

Question 21

what does it mean when a patient’s kidneys stopped working properly

Answer 21

they can’t filter their blood properly

Question 22

flow of dialysis fluid and blood to maintain what

Answer 22

Dialysis fluid and blood will flow counter current to each other to maintain a concentration gradient for diffusion of urea across the whole membrane.

Question 23

Advantages and disadvantages of dialysis

Answer 23

it can provide a patient with valuable time until a donor is found
A dialysis session has to be done regularly the three times a week with each session taking hours
restricted diet
an unpleasant experience

Question 24

what is the only cure for kidney failure

Answer 24

Kidney transplant

Question 25

why might patients have to wait a long time for a kidney transplant

Answer 25

people can live with only one kidney, so it is sometimes transplanted from volunteers which is usually a family member however the number of kidneys that are donated is much lower than the number of patients that need a kidney transplant

Question 26

how can a donor kidney be rejected?

Answer 26

By a patient’s immune system as it’s treated like a foreign body and attacked by antibodies

Question 27

1 advantage and 2 disadvantages of a kidney transplant

Answer 27

Can last 12-15 years with minimal medical intervention. Immunosuppressant drugs must be taken to avoid rejection. A donor must be found and must have a similar tissue type to the recipient, so a close family living donor is preferable.

Question 28

What is the amount of water reabsorbed in the kidney nephrons is controlled by?

Answer 28

anti diuretic hormone (ADH)

Question 29

The presence of what in the urine can indicate kidney damage or disease

Answer 29

Blood cells and proteins as they are usually not able to pass through the kidney membrane

Question 30

What can a high concentration of glucose in the urine indicate and how does this occur

Answer 30

that they have diabetes as in a healthy person almost all the glucose is reabsorbed in the nephron so it doesn’t enter the urine. However if a person has diabetes the concentration of glucose in the blood can become so high that the kidney can absorb it all.

Question 31

how can you test an artificial urine sample for glucose?

Answer 31

Add a few cm3 of the artificial urine sample to a boiling tube Add a few cm3 of Benedict’s Regent Place the boiling tube in water bath of 75° If glucose is present, a coloured precipitate will form eg brick red = high concentration

Question 32

how can you test an artificial urine sample for proteins?

Answer 32

Add a few cm3 of the artificial urine sample to a boiling tube Add a few cm3 of biuret solution shake the boiling tube gently if proteins are present, then the solution will turn violet if not it’ll stay blue

Question 33

how do you ensure the urea diffuses out of the blood into the dialysis fluid?

Answer 33

Dialysis fluid contains equal - concentration of glucose and salts that should not be removed from the blood. It contains no urea and so urea will diffuse from a high concentration in the blood out into the dialysis fluid which is then disposed of.

Question 34

what happens if the water content of the blood is too low

Answer 34

The brain detects the water content of the blood is too low. More ADH is released into the blood from the pituitary gland. Blood takes more ADH to the collecting duct of the kidney. The collecting duct becomes more permeable to water. osmosis. Water in the collecting duct is reabsorbed into the blood by A small volume of concentrated urine is released.

Question 35

What happens if the water content of the blood is too high?

Answer 35

The brain detects the water content of the blod is too high. Less ADH is released into the blood from the pituitary gland Blood takes less ADH to the collecting duct of the kidney The collecting duct becomes less permeable to water. Water is retained in the collecting duct A large volume of dilute urne is released.