The Kidneys

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  • Created by: Christie
  • Created on: 14-05-13 11:50
What 3 main roles do the kidneys perform?
Removal of urea from the blood, adjustment of ion levels in the blood, adjustment of water content in the blood
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What are Nephrons?
Filtration units in the kidneys
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Explain the process of ultrafiltration
A high pressure is built up which squeezes water, urea, ions and glucose out of the blood into the Bowman's capsule. The glomerulus and the Bowman's capsule act like filters so big molecules e.g. proteins and blood cells are not squeezed out.
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Explain the process of reabsorption
As the liquid flows along the nephron useful substances are reabsorbed e.g. all glucose and water. Glucose is moved out of the nephron and back into the blood against the concentration gradient. Sufficient water is reabsorbed according to ADH levels
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What is osmoregulation?
The process of maintaining the right water content in the body
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What happens to waste substances?
Urea and excess water continue out of the nephron and into the ureter, then down into the bladder as urine where they're released through the urethra
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Water content is controlled by a 'what' feedback system?
Negative
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Explain the process of negative feedback
Where changes in the environment trigger a response that counteracts the changes. This means that the internal environment stays at the level at which the cells work best.
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What hormones controls the amount of water reabsorbed in the kidney nephrons?
Anti-diuretic hormone (ADH)
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Explain how negative feedback brings the water level in the blood back to normal through negative feedback.
Water loss - pituitary gland releases more ADH - ADH makes kidney reabsorb more water. // Water gain - pituitary gland releases less ADH - lack of ADH means kidney reabsorbs less water.
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How does a dialysis machine work?
Dialysis fluid has the same concentration of salts and glucose as blood plasma, therefore those aren't removed from the blood. The barrier is permeable to ions and waste substances (not big molecules), so these move across into the dialysis fluid.
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What can be done to cure Kidney disease?
A kidney transplant
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Where are healthy kidneys usually transplanted from?
People who have died suddenly who are on the organ donor register or that carry a donor card.
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To prevent a kidney being rejected by a patients immune system, what precautions are taken?
A donor with a tissue type that closely matches the patients is chosen. The patient is given drugs that suppress the immune system, so their immune system won't attack the kidney.
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Other cards in this set

Card 2

Front

What are Nephrons?

Back

Filtration units in the kidneys

Card 3

Front

Explain the process of ultrafiltration

Back

Preview of the front of card 3

Card 4

Front

Explain the process of reabsorption

Back

Preview of the front of card 4

Card 5

Front

What is osmoregulation?

Back

Preview of the front of card 5
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