Excretion

Question 1

What are the metabolic reactions within the body do?

Answer 1

They are always creating waste products.

Question 2

What is excretion?

Answer 2

It is defined as the removal from organisms of toxic materials and substances in excess of requirement

Question 3

What are the two main sets of excretory organs for removing metabolic waste products?

Answer 3

The lungs that excrete carbon dioxide and the kidneys that excrete urea - excess salts and water.

Question 4

What supplies blood to the kidneys

Answer 4

The renal artery

Question 5

What returns blood from kidney to the rest of the circulation

Answer 5

The renal vein

Question 6

What is the job of the kidney

Answer 6

To filter urea and salts from the blood

Question 7

What allows urine to leave the body via the urethra?

Answer 7

The relaxation of the bladder sphincter.

Question 8

What is your urine?

Answer 8

Urine = urea + ions + toxins + water

Question 9

What happens to amino acids that are in excess

Answer 9

They are not stored. They are changed by the liver to urea.

Question 10

Why should a balanced diet contain protein

Answer 10

Balance diet will always contain proteins whose constituent amino acid’s will be used by the cells to manufacture the particular proteins we need.

Question 11

What is the name of the blood vessel that links the kidney with the inferior Vena cava

Answer 11

Renal vein

Question 12

Why is the removal of faeces not considered to be an important form of excretion?

Answer 12

Faeces are largely undigested Cellulose and lignin(fibre) that has never taken part in a chemical reaction in the body. These chemicals are therefore not excretory products.
The fact that the liver deals with the amino acid’s that have been absorbed from the alimentary can now, means that it is therefore involved in there assimilation.

Question 13

What is assimilation?

Answer 13

Is the movement of digestive food molecules into the cells of the body where they are used

Question 14

What happens during the assimilation of amino acid’s

Answer 14

That required amino acid are all linked together to make proteins some of which will be plasma proteins that are then released into the blood

Question 15

What happens to excess amino acid’s

Answer 15

During a process called daemination, it breaks them down into urea which is released into the blood and into a carbohydrate, which is converted into glycogen and stored into the cells of the liver.

Question 16

What is daemination

Answer 16

Is defined as the removal of the nitrogen containing part of amino acids to form urea

Question 17

Why can fruit be put into an atmosphere enriched with carbon dioxide

Answer 17

Corbin dioxide has a narcotic effect on living cells. Fruit can be sorted after picking in an atmosphere in enriched with carbon dioxide to slow down the cells metabolism and thus slowdown the ripening process.

Question 18

How is the kidney supplied with blood

Answer 18

From the renal artery

Question 19

What is the outer part of the kidney called

Answer 19

The cortex

Question 20

What is the inner part of the kidney called

Answer 20

The medulla

Question 21

What is in the centre of the kidney

Answer 21

Is a space from which the Ureter leads to the bladder

Question 22

What is the Glomerulus

Answer 22

In each kidney, the renal artery divides burst into Arterioles then into the capillaries . these capillaries form around 1 million minute clumps or knots. The correct name for one of these knots is that glomerulus

Question 23

What does the glomerulus supply?

Answer 23

Kidney tubules or nephron and each tubule starts with a cup shaped structure called a renal capsule.
All the renal capsules lie in the cortex of the kidney

Question 24

What happens under the pressure of the renal capsule

Answer 24

The blood in the knot of the capillaries is forced out through the capillary walls and through the walls of the capsule into the renal tubules. The high-pressure at filtration of the blood causes water, glucose, urea, salts and toxins to leave the blood and pass in to the tubule.

Question 25

What is selective reabsorption

Answer 25

Moving from a knot of capillaries, a capillary passes to the rest of the tubule and wrapped it self in close contact around the tubule. As the filtrate passes through the tubule , The capillary absorbs all of the substances that the body cannot afford to lose the following of reabsorbed into the blood;
All of the glucose unless the person is diabetic
Most of the water
Some of the salts

This leaves in the tubule a concentrated solution of urea, salts and toxins otherwise known as urine

Question 26

What is Osmoregulation

Answer 26

ensuring that the blood remains at a more or less constant concentration.

Question 27

How does kidney dialysis work

Answer 27

Kidney dialysis machine removes from a patient’s blood chemicals with small molecules (toxins, urea, and ions). What does not allow larger molecules such as plasma proteins or blood cells to leave the blood
This is achieved by passing the patient’s blood through dialysis tubing that is partially permeable (Permeable to only small particles)
This tubing is then placed in a dialysis or washing fluid which is continuously renewed and washes away the substances removed from the blood. By varied of the concentration of glucose and salts in the washing fluids, the amount of those substances that diffuse from the blood can be controlled and in this way, so can concentration of the plasma in the blood that is then returned to the patient.

Question 28

What are the advantages of having a kidney transplant

Answer 28

Permanent solution
Patient can live a normal life
Less expensive than dialysis
Fewer restrictions on diet

Question 29

What are the disadvantages of a transplant

Answer 29

There is a shortage of suitable donors
Anti rejection drugs would have to be taken
Transplanted kidney are made of foreign proteins causing the production of antibodies which may lead to rejection of the organ. The transplant is more likely to be successful if the donor is a close relative with a similar protein type.

Question 30

What is the advantage of dialysis

Answer 30

Immediate solution

Question 31

What is the disadvantage of dialysis

Answer 31

Needs to undergo every three days

Risk of infection

Question 32

Which part of the kidney do the glomeruli Lie?

Answer 32

The cortex

Question 33

Which substance is filtered from the blood by the kidneys but does not appear in the urine of a healthy persons blood.

Answer 33

Glucose