Homeostasis and the Kidneys

Question 1

What is homeostasis?

Answer 1

The maintenance of a constant internal environment.

Question 2

What are the six things to be controlled?

Answer 2

1. Body temperature
2. Water content
3. Ion content
4. Blood sugar levels
5. Carbon dioxide
6. Urea

Question 3

Why must body temperature be regulated?

Answer 3

1. Enzymes won’t work

2. Important reactions disrupted

Question 4

How is body temperature monitored?

Answer 4

Thermoregulatory centre in brain receives impulses from blood temperature in brain and in skin.

Question 5

What happens if you’re too hot?

Answer 5

1. Hairs lie flat.
2. Sweat produced and evaporates, taking away heat
3. Blood vessels dilate, so more blood flows closer to surface - easier for heat to be transferred to environment

Question 6

What happens if you’re too cold?

Answer 6

1. Hairs stand up to trap insulating layer of air
2. No sweat produced
3. Blood vessels constrict to close off skin blood supply
4. Shiver - respiration generates warmth

Question 7

What do the kidneys do?

Answer 7

1. Removal of urea
2. Adjustment of ions
3. Adjustment of water content

Question 8

What is urea?

Answer 8

A waste product of the conversion of amino acids into fats and carbohydrates.

Question 9

Why must urea be removed?

Answer 9

Poisonous.

Question 10

How is urea removed?

Answer 10

1. Released into blood by liver.
2. Kidney filters it out of blood.
3. Stored in bladder and excreted.

Question 11

What are the consequences of wrong ion content?

Answer 11

Disrupted osmotic balance.

Question 12

How are excess ions removed?

Answer 12

Kidneys.

Question 13

How is water lost from the body?

Answer 13

1. Urine
2. Sweat
3. Air breathed out

Question 14

How is water balanced in the body?

Answer 14

1. Liquids consumed
2. Amount sweated out
3. Amount excreted by the kidneys in urine

Question 15

How do sports drinks work?

Answer 15

1. Water and ions replace those lost in sweat

2. Sugar replaces sugar used by muscles

Question 16

How does ultrafiltration work?

Answer 16

1. High pressure squeezes blood through membrane
2. Water, urea, ions and sugar enter Bowman’s capsule
3. Big molecules stay in blood

Question 17

What is reabsorbed by the kidney?

Answer 17

1. All the sugar
2. Some ions
3. Some water

Question 18

How are ions reabsorbed into the blood?

Answer 18

Active transport.

Question 19

What happens to substances that aren’t reabsorbed?

Answer 19

Continue out of nephron into ureter and down to bladder as urine.

Question 20

What happens if the kidneys don’t work properly?

Answer 20

1. Waste substances build up in the blood
2. You cannot control the ion and water levels in your body
3. Eventual death

Question 21

What are the two treatments for kidney failure?

Answer 21

1. Dialysis

2. Kidney transplant

Question 22

Why does dialysis have to be done regularly?

Answer 22

1. Keep concentrations of dissolved substances in the blood at normal levels
2. Remove waste substances

Question 23

Why aren’t dissolved ions and glucose lost from the blood during dialysis?

Answer 23

The dialysis fluid has the same concentration of dissolved ions and glucose as healthy blood.

Question 24

What is the problem with dialysis?

Answer 24

Blood clots or infections.

Question 25

Where do healthy kidneys come from?

Answer 25

1. People who died and are on the organ donor register. | 2. Live organ donors.

Question 26

Why are donor kidneys rejected?

Answer 26

The foreign antigens on the donor kidney are attacked by the patient's antigens.

Question 27

What precautions are taken to reduce chance of organ rejection?

Answer 27

1. Donors are chosen by tissue type | 2. Immunosuppressive drugs

Question 28

How does glucose enter the blood?

Answer 28

Carbohydrates are absorbed into the blood by the gut.

Question 29

How is glucose removed from the blood?

Answer 29

1. Normal cell metabolism | 2. Vigorous exercise (much more)

Question 30

What happens if blood glucose level is too high?

Answer 30

1. Insulin secreted by pancreas 2. Liver turns glucose into glycogen 3. Insulin removed by liver

Question 31

What happens if blood glucose level is too low?

Answer 31

1. Glucagon secreted by pancreas 2. Liver turns glycogen into glucose 3. Glucagon removed by liver

Question 32

What is type one diabetes caused by?

Answer 32

Lack of insulin.

Question 33

What happens if type one diabetes isn't treated?

Answer 33

Blood glucose can rise to a level that can kill them.

Question 34

How can blood glucose level be controlled?

Answer 34

1. Controlling diet (less sugar) 2. Exercise 3. Insulin therapy

Question 35

How does insulin therapy work?

Answer 35

Injecting insulin so that glucose is removed from the blood once the food has been digested.

Question 36

Where did insulin used to come from?

Answer 36

Pig and cow pancreases.

Question 37

What was wrong with animal insulin?

Answer 37

Caused adverse reactions.

Question 38

What is the problem with insulin therapy?

Answer 38

Not as accurate as an actual pancreas.

Question 39

What is the problem with a pancreas implant?

Answer 39

Could cause tissue rejection - immunosuppressive drugs are expensive and have serious side-effects.

Question 40

What modern research could eliminate organ rejection?

Answer 40

Artificial pancreases and stem cell research.