B3 - Controlling internal

Question 1

What’s homeostasis

Answer 1

Keeping the conditions within a narrow range constant

Question 2

In the body what must be kept constant

Answer 2

Temperature 
Water 
Ions
Waste levels
Blood
Glucose

Question 3

What are the waste products that need to be removed from the body?

Answer 3

Urea
Excess water
Carbon dioxide

Question 4

How is urea made

Answer 4

Produced in the liver from the breakdown of amino acids, temporarily stored in the bladder and filtrated by the kidneys and passed trough urine

Question 5

What exactly do the kidneys do?

Answer 5

Filter the blood

Reabsorb ALL the glucose
Reabsorbing needed ions
Reabsorbing needed water

Releases urea (picked up along the way) excess ions and water

Question 6

What is dialysis

Answer 6

A replacement for kidneys

Blood passes through tubes and passes dialysis liquid through a partially permeable membrane and absorbs the waste.

Question 7

Advantages and disadvantages of dialysis

Answer 7

A - Better than death

D - Regular hospital trips (3 times a week) Could be for life

Question 8

Why might the body reject a kidney?

Answer 8

There lie antigens on the surface of the cells which can be seen as foreign so the recipients body attacks them thinking they’re dangerous.

Question 9

What are immunosuppressant drugs

Answer 9

Drugs to prevent rejection

Question 10

Why must body temperature be kept the same?

Answer 10

At 37 degrees so that enzymes can work efficiently and not denature

Question 11

How does the body regulate temperature in the body?

Answer 11

In the thermoregulatory centre in the brain
Receptor cells detect the blood temperature flowing through the brain
Skin receptors also send signals to the centre to tell the temperature and whether to increase or reduce blood flow

Question 12

How does sweating cool the body

Answer 12

More water is lost from the body when it’s hot due to increase rate of evaporation.

Question 13

If core temperature rises what does the brain do

Answer 13

• Blood vessels dilate allowing more blood to flow through, more energy is radiated away
• Sweat glands produce more sweat
• Body hair lies flat

Question 14

If core temperature falls what does the brain do

Answer 14

• Blood vessels constricts so blood flow decreases, less energy is radiated
• No sweat is produced
• Body hair stands erect and traps a layer of insulating air
• When we shiver our muscles contract and this requires energy so our blood warms

Question 15

Name 5 things doctors have to consider when prescribing different treatments

Answer 15

General health
Length the patient has been on dialysis
Costs
Risks of infection
Ethical issues such as the waiting list and whether the wealthy can get to the front

Question 16

What monitors our blood glucose and how

Answer 16

The pancreas
If there is too much glucose in our blood the pancreas produces insulin which causes the glucose to move from the blood to the cells

Question 17

In the liver what happens to excess glucose?

Answer 17

Converted to glycogen for storage

Question 18

Why do children and the elderly have to be considered for temperature change

Answer 18

Children have a large sa to volume so they release a lot of energy and dehydrate quickly when it’s hot which means enzymes denature

The elderly die from hypothermia because they do not move, muscle contract and cant release energy

Question 19

What if no, or little levels of insulin are created?

Answer 19

Blood glucose levels become too high and this is known as type 1 diabetes

Question 20

What happens when insulin is released

Answer 20

Causes the blood glucose level to fall
If it gets too low receptors in the pancreas detect it. So, the pancreas releases glucagon which causes the stored glycogen to change back into glucose.

Question 21

How is type 1 diabetes treated

Answer 21

Genetically engineered bacteria with human insulin which must be injected before every meal for the rest of their life

Question 22

Name some new methods created that can help cure type 1 diabetes

Answer 22

Pancreas transplants

Embryonic stem cells