Biology Unit 3 - Kidneys, Dialysis and homeostasis

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What must be controlled and kept constant in the body?
Temperature, blood glucose, water, ion content and levels of waste.
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What waste products need to be removed from the body?
Carbon dioxide produced in respiration removed via the lungs when we exhale. Urea, produced in the liver from the breakdown of amino acids, removed by the kidneys in the urine and temporarily stored in the bladder.
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What is meant by homeostasis?
Keeping the internal conditions of the body carefully controlled within a narrow range.
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Why do water and ion content need to be controlled?
Water and ion content must be controlled because if water or ion content are wrong, too much water could move in or out of cells and this could damage the cells
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How many kidneys does the body have?
Two kidneys
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What are the main functions of the kidney?
To filter the blood, by excreting substances you do not want and reabsorbing substances we need
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How does a healthy kidney produce urine?
1. The kidney filters the blood. 2.Reabsorbs all the sugar, dissolved ions needed by the body, and as much water as the body needs 3. Kidney releases urea, excess ions and water in the urine.
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Where is urea stored and what is made from?
Urea is stored in the liver and its the product of the breakdown of amino acids.
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Why is dialysis necessary for some people?
If a patient's kidneys do not work they can be kept alive by dialysis.
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Explain the process of dialysis.
Arterial blood passes through blood thinners (anticoagulants) into dialysis machine. Dialysis fluid is pumped into the machine. Blood flows over a partially permeable membrane. Excess substances like urea diffuses out of blood.
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Why does dialysis fluid contain glucose and mineral ions?
Dialysis fluid contains the same concentration of useful substances that the patient's blood does, eg/gluocose and mineral ions, so they do not diffuse out of the blood or need to be reabsorbed.
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How does the blood know which substances need to diffuse out of the dialysis membrane?
Apart from the glucose and mineral ions, if the concentration of one substance eg/salt is greater on one side of the membrane it will diffuse in or out down the concentration gradient.
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What cannot pass through the dialysis membrane?
Blood cells and large proteins.
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Why is urea diffused out of the blood?
Because the concentration of urea is greater in the blood than in the dialysis fluid, it so it diffuses out down the concentration gradient.
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How does clean blood get back into veins after going through the dialysis machine?
Clean blood goes through a bubble trap to remove any bubbles and returns to the patient's vien.
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Why can a donor kidney be rejected by our immune system?
Antigens on cells of the donated kidney may be different to the recipient's antigens. Therefore whiteblood cells will be stimulated to produce antibodies and attack new kidney.
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Which chemical gives urine a yellow colour?
Urobilin
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How do we prevent kidney rejection?
Use a kidney with the same tissue type. Use immunosupressant drugs.
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Name some advantages of dialysis.
No major surgery is needed. No waiting lists- people will not suffer.
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Name some disadvantages of dialysis.
One's diet must be controlled very carefully. Dialysis must be carried out at regular intervals and this takes 8 hours several times a week- restriction on normal life.
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Name three advantages of kidney transplants.
No need for dialysis. The recipient can lead a relatively normal life. The patient's diet does not need to be carefully controlled.
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Name some disadvantages of a kidney transplant.
Surgery has risks. Possibility of kidney rejection. Immunosuppresant drugs must be taken for life- this can leave patients vulnerable to other diseases or virus'. A donated kidney only lasts for about 9 years. Religious reasons.
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Other cards in this set

Card 2

Front

What waste products need to be removed from the body?

Back

Carbon dioxide produced in respiration removed via the lungs when we exhale. Urea, produced in the liver from the breakdown of amino acids, removed by the kidneys in the urine and temporarily stored in the bladder.

Card 3

Front

What is meant by homeostasis?

Back

Preview of the front of card 3

Card 4

Front

Why do water and ion content need to be controlled?

Back

Preview of the front of card 4

Card 5

Front

How many kidneys does the body have?

Back

Preview of the front of card 5
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