B3- Keeping Internal Conditions constant

Question 1

What are the advantages and disadvantages of using dialysis for kidney disease?

Answer 1

A- Available to all patients (no shortage).

A- No need for immunosuppressant drugs.

D- Patients must limit salt and protein intake.

D- Expensive for the NHS.

D- Regular dialysis sessions➡️Impact on the patient’s life.

Question 2

What happens when the body is too hot?

Answer 2

• Arteries supplying capillaries dilate (muscles relax). This increases blood flow into capillaries and near the surface of the skin to increase the amount of heat loss by radiation.
• Sweat glands secrete swear➡️Evaporation of sweat requires energy which comes from the skin’s surface so cools the skin down.

Question 3

What are the advantages and disadvantages of having a kidney transplant?

Answer 3

A- Patients can lead a more normal without having to watch what they eat and drink.

A- Cheaper for NHS overall.

D- Must take immunosuppressant drugs which increase risk of infection.

D- Shortage of organ donors.

D- Kidney only lasts 8-9 years on avergae.

D- Any operation carries risk.

Question 4

How can kidney disease be treated?

Answer 4

Either by dialysis or transplant.

Question 5

Why is insulin produced, and what does it do?

Answer 5

Insulin is produced when there is too much glucose in the blood.

Insulin converts glucose to glycogen for storage in the liver and muscles.

Question 6

What causes type 1 diabetes and how is it treated?

Answer 6

If the pancreas is unable to produce enough insulin, the blood glucose level may become too high.

Type 1 diabetes is traditionally treated with human insulin produced by genetically engineered bacteria. The diabetic must inject themselves with insulin before meals.

Question 7

How do the kidneys keep the body the same?

Answer 7

Kidneys keep water and ion concentration constant.

Question 8

What is urea?

Answer 8

Urea is produced in the liver when excess protein is taken in. This cannot be stored so the protein is broken down in urea.

Question 9

During exercise, why would the skin surface temperature decrease?

Answer 9

Increased sweating (1) which evaporates and uses energy, so cools the skin (1).

Question 10

What is in dialysis fluid?

Answer 10

Dialysis fluid contains the same concentration of useful substances as the body needs (water, glucose and ions) so the substances do not diffuse into the dialysis fluid.

There is no urea in the fluid, therefore urea in the blood diffuses into the fluid and so is removed from the blood.

Question 11

Why is body temperature kept the same?

Answer 11

The body is kept at 37^o so that enzymes can work quickly, but do not denature.

Question 12

What is meant by homeostatis?

Answer 12

This means keeping the body in the same/a steady state.

Question 13

What happens when the body is too cold?

Answer 13

• Arteries supplying capillaries constrict (muscles contract). This means less blood flows in capillaries and near the surface of the skin, so less heat is lost by radiation.
• We shiver (muscles contract quickly) which increases the rate of respiration and some energy released warms the blood.
• Hair stands erect➡️Traps warm layer of air (more in animals).

Question 14

What is a dialysis machine?

Answer 14

A dialysis machine carries out the same job as the kidneys. It filters the blood using a partially permeable membrane, and restores the concentration of substances in the blood back to normal.

Question 15

How is blood glucose level kept the same?

Answer 15

The pancreas releases insulin when blood glucose rises, and glucagon when blood glucose falls.

Question 16

Why must immunosuppressants be taken after a kidney transplant?

Answer 16

The antigens on the donor organ may be attacked as the recipient’s immune system sees the antigens as ‘foreign’. Therefore immunosuppressant drugs must be taken to prevent rejection.

Question 17

During exercise, why would the core body temperature increase?

Answer 17

Increased respiration, so more energy released.

Question 18

What new methods are being developed to treat type 1 diabetes?

Answer 18

• Pancreas transplants.
• Transplanting pancreas cells.
• Using embryonic stem cells to produce insulin secreting cells.
• Using adult stem cells from diabetic patients.
• Genetically engineering pancreas cells to make them work properly.

Question 19

What happens if body temperature is not kept constant?

Answer 19

• If body temperature is too low the respiratory ezymes work too slowly and too little energy is released.
• If body temperature is too high enzymes can denature.

Question 20

Where is blood temperature monitored?

Answer 20

Thermoregulatory centre in the brain (hypothalamus). This centre has receptors which detect the temperature of the blood flowing through the brain.

Question 21

What does a healthy kidney do?

Answer 21

A healthy kidney:

1. Filters the blood.
2. Reabsorbs all the sugar.
3. Reabsorbs as much water and ions as the body needs.
4. Releases urea, excess ions and water in the urine.

Question 22

Why is glucagon produced, and what does it do?

Answer 22

Glucagon is produced when there is not enough glucose in the blood.

Glucagon converts glycagen back to glucose.

Question 23

How is blood filtered in the kidneys?

Answer 23

Nephrons.