Kidney function and failure

Question 1

What are the filtration units in the kidneys called?

Answer 1

Nephrons

Question 2

What happens in ultrafiltration? (2)
Squeeze
Membranes

Answer 2

High pressure is built up which squeezes water urea, ions and sugars out of the blood into the Bowman’s capsule
The membranes between the blood vessels and the Bowman’s capsules act like filters so big molecules like proteins and BCells are not squeezed out, they stay in the blood.

Question 3

Describe a single Nephron - a filtration unit in a kidney

1. Blood in…
2. The web, C
3. The molecules
4. Capillaries
5. Blood off…
6. Urine off…

Answer 3

The blood flows in through the renal artery
The artery splits up and looks like a web touching a backwards C called a Bowman’s capsule
The filtrated molecules flow down a winding yellow tubule
The winding yellow tube is tangled with a series of red tubes, the capillary network where reabsorbtion takes place
The capillaries rejoin to form the renal vein
The yellow tube meats the collecting duct which transports the urine into the bladder

Question 4

What is reabsorbed?
What happens through reabsorbtion?
S
I
W

Answer 4

Useful substances
All the sugar is reabsorbed, through active transport against the concentration gradient
Sufficient ions are reabsorbed, excess ions are not, through active transport
Sufficient water is reabsorbed

Question 5

How are the excess products wasted from the filtration in the kidneys?

Answer 5

Urea etc continue out of the Nephron and down into the ureter into the bladder as urine

Question 6

Each kidney contains about ….Nephrons

Answer 6

1 million

Question 7

What are the two treatments for kidney failure to keep people alive?

Answer 7

Regular dialysis treatment where machines do the jobs of the kidneysor a kidney transplant

Question 8

What do the kidneys do?

Answer 8

Remove waste substances from the blood

Question 9

What happens if the kidneys don’t work properly?

Answer 9

Waste substances build up in the blood and you lose your ability to control the ion and water levels in the blood, this eventually results in death.

Question 10

Where are the problems you can get with kidney failure?

Answer 10

Heart, bones, nervous system, mouth etc

Question 11

What do dialysis machines do?

Answer 11

Filter the blood

Question 12

Why does dialysis have to be done regularly? (2)

Answer 12

To keep the concentrations of dissolved substances in the blood at normal levels and to remove waste substances

Question 13

What happens in a dialysis machine?
Flow
P to what?
In the dialysis fluid
This means that...
So only... using what transport?

Answer 13

The person’s blood flows alongside a SELECTIVELY permeable barrier surrounded by dialysis fluid.
It is permeable to ions, waste substances but not big molecules like proteins, just like the kidney membrane
The dialysis fluid has the same concentration of dissolved ions and glucose as healthy blood.
This means the useful dissolved ions and glucose won’t be lost from the blood during dialysis.
This means only waste substances (urea) and excess ions and water diffuse across the barrier

Question 14

How often and for how long to dialysis patients need treatment?

Answer 14

Three times a week for 3-4 hours

Question 15

What can dialysis cause?

Answer 15

Blood clots or infections

Question 16

What is the problem with transplanted organs?

Answer 16

They are rejected by the body

Question 17

What is the only cure for kidney disease?

Answer 17

Kidney transplant

Question 18

What are healthy kidneys usually transplanted from?

Or?

Answer 18

People who have died suddenly, car accidents por ejemplo, who have an organ donor card or are on the register, provided their relatives give the ‘go ahead’.
From people who have two healthy ones and volunteer

Question 19

What are the kidneys rejected by?

How and with what?

Answer 19

The patient’s immune system

The foreign antigens on the donor kidney are attacked by the patient’s antibodies

Question 20

How are rejections to kidneys prevented?
The same …. What is this based on?
What are used to stop what?

Answer 20

A donor with the same tissue type that closely matches is used. The tissue type is based on antigens, the proteins on the surfaces of most cells.
Drugs are used to treat the patient to supress the immune system so that it won’t attack the transplant

Question 21

What are the negatives for dialysis …

and transplants?

Answer 21

.. the machines are expensive for the NHS, the process is time consuming and boring and not a plesent experience
Transplants are cheaper and can put an end to the hours spent on the dialysis machines but the waiting lists are long. If you do get a similar tissue type there is still a chance of it being rejected.
Taking the immunosupressents makes the patient vulnerable to illness.