B3.3 Homeostatis

Question 1

Name two waste products that have to be removed from the body.

Answer 1

1. Carbon Dioxide - removed when we breathe out.

2. Urea

Question 2

How does a healthy kidney produce urine? (5)

Answer 2

• First filtering the blood.
• Reabsorbing all the sugars
• Reabsorbing the dissolved ions needed by the body.
• Reabsorbing as much water as the body needs.
• Releasing urea, excess ions and water as urine.

Question 3

People who suffer from kidney failure may be treated by which two treatment procedures?

Answer 3

Kidney Dialysis machine

Healthy Kidney transplant

Question 4

Describe the process of how a dialysis machine works? (5)

Answer 4

• Restores the concentration of dissolved substances in the blood to normal levels, this must be carried out at regular intervals.
• Blood flows through partially permeable membranes.
• Dialysis fluid contains same concentration of useful substances as the blood.
• This ensures that glucose and useful mineral ions are not lost.
• Urea passes out from the blood into the dialysis fluid.

Question 5

Describe the process of how a kidney transplant works?

Answer 5

• Diseased kidney is replaced with a healthy one from a donor.

Question 6

Name one precaution that must be taken while having a kidney transplant?

Answer 6

The donor kidney may get rejected by the immune system, as the user’s antibodies may attack the antigens on the donor organ, as they don’t recognise them.

Question 7

How can you prevent the rejection of a healthy kidney?

Answer 7

• Use a donor kidney with a ‘tissue - type’ similar to that of the recipient.
• Recipient is treated with drugs that suppress the immune system.

Question 8

What are antigens?

Answer 8

Proteins on the surface of cells.

Question 9

What are the kidney tubules?

Answer 9

The structure in the kidney that filters and absorbs substances.

Question 10

True or False: Sweating helps to cool the body?

Answer 10

True

Question 11

Which organ is responsible for controlling and monitoring the body temperature?

Answer 11

Thermoregulatory centre (in the brain).

Question 12

What structure is in the Thermoregulatory centre that helps it to monitor and control temperature?

Answer 12

It has receptors sensitive to the temperature of the blood flowing through the brain.

Also temperature receptors in the skin send impulses to it, giving information about skin temperature.

Question 13

If the core temperature is too high, what are the two things that the body does?

Answer 13

• Blood vessels supplying the skin capillaries dilate (widen) to allow more blood flowing through the capillaries and more heat is lost.
• Sweat glands release more sweat which cools the body as it evaporates.

Question 14

If the core temperature is too low, what are the two things that the body does?

Answer 14

• Blood vessels supplying the skin capillaries constrict (narrow) to reduce the flow of blood through the capillaries.
• Muscles may ‘shiver’ - contraction requires respiration which releases some energy to warm the body.

Question 15

The blood glucose concentration is monitored and controlled by which organ?

Answer 15

Pancreas

Question 16

Where is insulin produced, and what is its role?

Answer 16

• Produced in the pancreas.

- Allows glucose to move from the blood to the cells.

Question 17

Where is glucagon produced, and what is its role?

Answer 17

• Produced in the pancreas.
• Produced when the blood glucose concentration levels fall.
• Causes glycogen to be converted back into glucose, and be released into the blood.

Question 18

What is type 1 diabetes?

Answer 18

A disease in which a person’s blood glucose concentration may rise to a high level because the pancreas does not produced enough insulin.

Question 19

How can type 1 diabetes be controlled?

Answer 19

Careful attention to diet, exercise or by injecting insulin.