Homeostasis

Question 0

What things need to be controlled?

Answer 0

Body temperature
Blood glucose levels
Water & ion content
Levels of waste products

Question 1

What is homeostasis?

Answer 1

Keeping internal conditions within a narrow range.

Question 2

What waste products have to be removed from the body in homeostasis?

Answer 2

Carbon dioxide & urea

Question 3

How is carbon dioxide produced and removed?

Answer 3

Produced by respiration and removed via lungs when we breathe out.

Question 4

How is urea produced and removed?

Answer 4

Produced by the liver from the breakdown of amino acids and removed by kidneys in urine which is temporarily stored in the bladder.

Question 5

What enters the body when we eat and drink?

Answer 5

Water and ions

Question 6

What happens if the water or ion content is wrong?

Answer 6

too much water may move out or into the cells and damage them.

Question 7

What is the function of the human kidney?

Answer 7

Filter blood, excrete unwanted substances, keep wanted substances.

Question 8

How does a healthy kidney produce urine?

Answer 8

1. filter the blood
2. reabsorbing all the sugar
3. reabsorbing dissolved ions needed by the body
4. reabsorbing as much water as the body needs
5. releasing urea, excess ions and water as urine.

Question 9

What are two methods of treating people with kidney failure?

Answer 9

Dialysis and kidney transplant

Question 10

What does dialysis do?

Answer 10

Restores the concentration of dissolved substances in the blood to normal levels.

Question 11

How often does dialysis need to be carried out?

Answer 11

At regular intervals

Question 12

How does dialysis work?

Answer 12

Blood flows between partially permeable membranes.
Dialysis fluid contains the same concentration of useful substances as the blood to ensure they don’t diffuse out of blood.
No urea in dialysis fluid so it diffuse out out blood.
Blood cells and large proteins can’t pass through dialysis membrane

Question 13

What is a kidney transplant?

Answer 13

Diseased kidney replaced with healthy one

Question 14

What is a problem with kidney transplants?

Answer 14

Recipients antibodies may attack the antigens on the donor organ because they recognise them as foreign.

Question 15

What are antigens?

Answer 15

Proteins on the surface of cells

Question 16

How can rejection be prevented?

Answer 16

New kidney must be a good tissue match
Recipient treated with drugs which suppress the immune system (immunosuppressant drugs) however this leaves them vulnerable to common infections

Question 17

What temperature must the human body be kept at and why?

Answer 17

37 degrees so that enzymes work efficiently

Question 18

What monitors and controls body temperature and how?

Answer 18

the thermoregulatory centre which is situated in the brain and has receptors which detect the temperature of the blood flowing through the brain.

Question 19

What to temperature receptors in the skins do?

Answer 19

send impulses to the thermoregulatory centre about skin temperature.

Question 20

What effect does sweating have on body temperature?

Answer 20

It cools the body down

Question 21

How can water loss be balanced?

Answer 21

Taking in more water through food and drink

Question 22

What happens to hair when core temperature is too high?

Answer 22

lie flat

Question 23

What happens to blood vessels near skin when core temperature too high?

Answer 23

Dilate to increase blood flow through skin capillaries. Energy is transferred by radiation so heat is lost

Question 24

What do sweat glands do when core temperature too high?

Answer 24

Release more sweat as it cools the body when it evaporates

Question 25

What happens to blood vessels when core temperature too low?

Answer 25

Constrict to decrease blood flow through skin capillaries so less heat is radiated

Question 26

What happens to hairs when core temp too low?

Answer 26

Pulled erect to trap insulating layer of air

Question 27

Why do we shiver when core temp too low?

Answer 27

Cause muscles to contract quickly so respiration required in which some of the energy released warms blood

Question 28

What monitors and controls blood glucose level?

Answer 28

pancreas

Question 29

What happens when glucose level are too high?

Answer 29

Pancreas produces insulin hormone Insulin causes glucose to move from blood to cells In liver, excess glucose converted to glycogen for storage

Question 30

What is glucagon?

Answer 30

hormone

Question 31

What happens when glucose levels too low?

Answer 31

Receptors in pancreas detect low level Pancreas release glucagon glucagon causes glycogen to be converted into glucose Glucose released back into blood

Question 32

What is type 1 diabetes?

Answer 32

High blood glucose level

Question 33

What causes type 1 diabetes?

Answer 33

Pancreas does not produce enough insulin

Question 34

How is type 1 diabetes controlled?

Answer 34

Injections of insulin | Careful attention to diet and levels of exercise

Question 35

How is type 1 diabetes traditionally treated?

Answer 35

Human insulin produced by genetically engineered bacteria

Question 36

When must a diabetic inject?

Answer 36

before meals