5.2.8- Kidney failure

Question 1

What is glomerular filtration rate?

Answer 1

The rate at which fluid enters the nephrons
Normal reading: 90-120cm3 min-1
Figure below 60cm indicates that there may be some form of chronic kidney disease.
Figure below 15cm indicates kidney failure

Question 2

What are monoclonal antibodies?

Answer 2

Antibodies made from one type of cell - they are specific to one complementary molecule

Question 3

What is a renal dialysis?

Answer 3

A mechanism used to artificially regulate the concentrations of solutes in the blood

Question 4

What is kidney failure?

Answer 4

Unable to regulate the levels of water and electrolytes (substances from charged particles) in the body to remove waste products such as urea from the blood –> Leads to death.

Question 5

How can the Kidney function be assessed

Answer 5

Estimating the Glomerular filtration rate and by analysing the urine for substances such as proteins –> Proteins indicate the filtration mechanism has been damaged

Question 6

What are the causes of kidney failure?

Answer 6

Diabetes mellitus, heat disease, hypertension and infection

Question 7

What are the two main treatments for kidney failure?

Answer 7

Renal dialysis and kidney transplant

Question 8

What is renal dialysis?

Answer 8

1) Waste products, excess fluid and mineral ions are removed from the blood by passing it over a partially permeable dialysis membrane —> Allows the exchange of substances between the between the blood and the dialysis fluid.
2) The dialysis fluid contains the correct concentrations of mineral ions, urea, water and other substances found in blood plasma. –> Excess substances in blood diffuse across the membrane into the dialysis fluid –> Any substances that are too low in concentration diffuse into the blood from the dialysis fluid

Question 9

What is haemodialysis?

Answer 9

1) Blood from an artery or vein is passed into a machinery that contains artificial dialysis membrane shaped to form many artificial capillaries –> Increases the surface area for exchange
2) Heparin is added to avoid clotting,
3) There is a counter current between the dialysis and the flow of blood –> Improves efficiency of exchange as there is a concentration gradient
4) Any bubbles are removed before the blood is returned to the body via a vein
5) Usually performed at a clinic two or three times a week for several hours at each session.

Question 10

What is peritoneal dialysis?

Answer 10

1) Dialysis membrane in the body’s own abdonminal membrane (peritoneum)
2) Surgeon implants a permanent in the abdomen
3) Dialysis solution is poured through the tube and fills the space between the abdominal wall and organs.
4) Several hours, the used solution is drained from the abdomen
5) PD can be carried out at home or work, patient can walk around while having dialysis, sometimes known as ambulatory PD

Question 11

What is a kidney transplant?

Answer 11

1) Surgeon implants the new organ into lower abdomen and attaches it to the blood supply and the bladder.
2) Patients are given immunosupressants drugs to help prevent their minnue system recognising the new organ as a foreign object and rejecting it.

Question 12

What are the advantages of kidney transplants? (4 points)

Answer 12

1) Freedom from time-consuming renal dialysis
2) Feeling physically fitter
3) Improved quality of life - able to travel
4) Improved self-image, no longer have a feeling of being chronically ill

Question 13

What are the disadvantages of kidney transplants? (4 Points)

Answer 13

1) Need to take immunosuppressant drugs
2) need for major surgery under general anaesthetic
3) Need for regular checks for signs of rejection
4) Side effects of immunosuppressant drugs - fluid retention, high blood pressure, susceptibility to infections

Question 14

How can Urine be analysed?

Answer 14

1) If these metabolic products are not reabsorbed further down the nephron they can be detected in urine

Question 15

What can urine be tested for? (5 points)

Answer 15

1) Glucose in diagnosis of diabetes
2) Alcohol to determine blood alcohol levels in drivers
3) Many recreational drugs (tests may be carried at random at work - especially where there are safety issues related to the type of work)
4) Human chorionic gonadotrophin (hCG) in pregnancy testing
5) Anabolic steriods, to detect improper use in sporting competitions

Question 16

How do you test for pregnancy?

Answer 16

1) Once human embryo implanted in uterine lining
2) Produces a hormone called human chorionic gondadotrophin (hCG - small glycoprotein)
3) Urine poured onto test stick
4) hCG binds to mobile antibodies attached to a blue bead
5) Mobile antibodies move down test stick
6) If hCG is present, it binds to fixed antibodies holding bead in place - a blue line forms
7) Mobile antibodies with no hCG attatched bind to another fixed site to show the test is working

Question 17

How are tests for Anabolic steriods carried out?

Answer 17

• Non- medical uses for anabolic steroids are controversial because they can give advantage in competitive sports and they have dangerous side effects.
• Anabolic setiods have a half-life of about 16 hours and remain in the blood for many days. –> Relatively small molecules and can enter nephron easily. testing for anabolic steroids involves analysing a urine sample in a laboratory using gas chromatography