B12

Question 1

What’s the optimum temp for enzymes in the body?

Answer 1

37 degrees C

Question 2

What does the thermoregulatory centre in the brain contain?

Answer 2

It contains receptors that are sensitive to the temp of the blood flowing through the brain

Question 3

How does the body measure the core temperature?

Answer 3

Temperature receptor cells in the hypolamus

Question 4

What do lungs remove?

Answer 4

Lungs remove carbon dioxide, a product of respiration

Question 5

What does the liver do?

Answer 5

The liver converts excess protein into urea

Question 6

What does the skin remove?

Answer 6

The skin provides a surface for small amounts of water and salt to move out of the body.

Question 7

What does the kidney remove?

Answer 7

The kidneys filter the blood, removing urea and excess water and salt, which forms urine. Urine is stored in the bladder before being excreted from the body.

Question 8

How is urea formed ?

Answer 8

Excess amino acids in the body are broken down by the liver, producing a waste substance called urea

Question 9

What is deamination?

Answer 9

Deamination is the removal of the amino group from the amino acid forming toxic ammonia, which is then immediatly converted into urea. The urea is then sent to the kidneys

Question 10

How is urine made?

Answer 10

The kidneys make urine by taking waste products outmof your blood

Question 11

Explain the process of filtration in the kidneys

Answer 11

Substances are filtered out of the blood as it passes through the kidneys.

Question 12

Why does carbon dioxide have to be removed from the body? And how is it removed?

Answer 12

Carbon dioxide is produced by the body cells during respiration and it must be removed from the body because dissolved carbon dioxide produces an acidic solution and this would effect the working enzymes in your cells. It diffuses from the blood into the air in the alveoli of your lungs. This air containing the excreted carbon dioxide is removed from your body when you exhale. As a side effect of exhalation, you lose water when the moist air from inside your lungs is forced out of the body.

Question 13

Why does urea have to be removed from your body? How is it removed?

Answer 13

It has to be removed because urea is poisonous and if levels build up in your body this will cause extensive damage to the cells. It is filtered out your blood by the kidneys and is then passed out the body in the urine produced by the kidneys, along with any excess water and salt

Question 14

How are water and minerals removed from the body?

Answer 14

Water, mineral ions, and urea are lost from the body in several ways.
Some of these methods give no control over the amount of the various substances lost to the environment.

Control:
-Urea, excess water, and excess mineral ions are removed from the body via the kidneys, then excreted in the urine.

No Control:
-Water leaves the lungs every time you exhale
-Water, mineral ions, and urea are lost through the skin in sweat

Question 15

What is the function of the kidneys?

Answer 15

Your kidneys are important for homeostasis in the water balance of your body.

If you are short of water, your kidneys conserve it. You produce very little, very concentrated urine and water is saved for use in your body.

If you drink too much water then your kidneys produce lots of dilute urine to get rid of the excess.

The concentration of mineral ions in your body is also important. You take in differing amounts of mineral ions with your food. Some are lost through your skin when you sweat. Your kidneys remove excess mineral ions and excrete them in your urine.

Question 16

What is selective reabsorption?

Answer 16

Useful substances like glucose, mineral ions and the right amount of water are then absorbed back into the blood.

Question 17

Proteins cant be stored in the body.
What happens to excess amino acids?

Answer 17

Excess amino acids are converted into fats and carbohydrates, which can be stored

Question 18

How is the concentration of urine controlled?

Answer 18

The concentration of urine is controlled by a hormone called anti-diuretic hormone (ADH)

The brain monitors the water content of the blood and instructs the pituitary gland to release ADH into the blood according to how much is needed

Question 19

The whole process of water content regulation is controlled by ….

Answer 19

Negative feedback meaning if the water content gets too high or too low a mechanism will be triggered that brings it back to normal (homeostasis)

Question 20

What happens if the water content inside the body is too much?

Answer 20

• A receptor in the brain detects that the water content is too high
• The coordination centre in the brain recieves the information and coordinates a response
• The pituitary gland releases less ADH, so less water is reabsorbed from the kidney tubules

Question 21

What happens if the content of water inside the body is too low?

Answer 21

• A receptor in the brain detects that the water content is too low
• The coordination centre in the brain recieves the information and coordinates a response
• The pituitary gland releases more ADH, so more water is reabsorbed from the kidney tubules

Question 22

What are some problems that could happen with kidneys?

Answer 22

Kidney stones:
- High salt and minerals in your diet can lead to stones precipitating out
- Extremely painful
- Has to be excreted from the body in the urine

Renal damage / failure:
- The kidney is no longer able to filter blood effective

Question 23

What is dialysis?

Answer 23

The function of the kidney is carried out artificially

Question 24

What do dialysis machines do?

Answer 24

In a dialysis machine the person’s blood flows between partially permeable membranes, surrounded by dialysis fluid. It’s permeable to things like ions and waste substances, but not big molecules like protein

Question 25

What does the dialysis fluid contain?

Answer 25

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

This means that useful dissolved ions and glucose won’t be lost from the blood during dialysis.

Only waste substances (such as urea) and excess ions and water diffuse across the barrier.

Question 26

How often do patients have to have dialysis treatment?

Answer 26

They have to have a dialysis session 3 times a week and each session is about 3-4 hours

Question 27

What are the disadvantages/Advantages of dialysis?

Answer 27

Disadvantages:
- Dialysis may cause blood clots or infections
- Not a pleasant experience and is very expensive to run
Advantages:
- Dialysis can buy a patient with kidney failure valuable time until a organ donor is found

Question 28

Where are kidneys usually transplanted from?

Answer 28

Healthy kidneys are usually transplanted from people who have died suddenly.
The person who died has to be on the organ donor register or carry a donor card

Kidneys can also be transplanted from people who are still alive ( as we have 2 of them ) but there is a small risk to the person donating the kidney

Question 29

What are the risks when donating a kidney?

Answer 29

There is also a risk that the donor kidney can be rejected by the patient’s immune system. The patient is treated with drugs to prevent this but it can still happen.

Question 30

What are the advantages / disadvantages of a kindey transplant?

Answer 30

Advantages:
Transplants are cheaper (in the long run) than dialysis and they can put an end to the hours patients have to spend on dialysis

Disadavntages:
But there are long waiting lists for kidneys

Question 31

What happens when kidneys don’t work properly? ( why is it a threat to life )

Answer 31

If the kidneys don’t work properly, waste substances build up in the blood and you lose your ability to control the levels of ions and water in your body. Eventually, this results in death.

Question 32

On what process does dialysis depend on?

Answer 32

Diffusion, down concentration gradient

Question 33

What does your body do when your too hot ?

Answer 33

1) Sweat is produced by sweat glands and evaporates from the skin. This transfers energy to the environment.

2) The blood vessels supplying the skin dilate so more blow flows closer to the surface of the skin. This is called vasodilation. This helps transfer energy from the skin to the environment.

Question 34

What does your body do when your too cold ?

Answer 34

1) Hairs stand up to trap and insulating layer of air
2) No sweat is produced
3) Blood vessels supplying skin capillaries constrict to close off the skin’s blood supply. This is called vasoconstriction
4) When your cold you shiver (your muscles contract automatically). This needs respiration which transfers energy to warm the body