I/GCSE Biology - Kidneys (1)

In I/GCSE Biology, the topic of kidney is commonly asked in exam!

• The Kidneys help maintain the internal environment by:
  1. Filtering the blood
  2. Reabsorbing all the sugar
  3. Reabsorbing the dissolved ions needed by the body
  4. Reabsorbing as much water as the body needs
  5. Releasing urea, excess salts and excess water as urine.
• Blood is brought to the kidneys from the renal arteries. Urea and other substances are filtered out of the blood to form urine.
• The cleaned blood flows out of the renal veins and the urine is excreted.

In I/GCSE Biology, it's important to memorize dialysis as well!

Dialysis

• Renal dialysis ➡️ an artificial kidney machine which filters the blood.
• The word ‘dialysis’ means ‘splitting into two’ and refers to the way a patient’s blood is purified by separating off the unwanted waste products such as urea by the dialysis membrane.
• The kidney dialysis machine works like a real kidney.
• The filter in the machine is visking tubing. The tiny holes allow small molecules such as water, ions, and urea pass through but not big molecules such as cells and proteins.
• One side of the membrane the patient’s blood flows and the other side a special dialysis fluid which has to be changed every few hours.
• To achieve dialysis it’s usually easier to use a vein that is closest to the skin and also has a large lumen. However, the pressure in a vein is low so has to be attached to an artery for the necessary pressure.
• The kidney dialysis is a complex and expensive piece of apparatus. A kidney transplant is preferred.

In I/GCSE Biology, you should understand how kidney transplant works!

• Humans can live happily with one kidney but when both kidneys fail they would die in a week because of the poisonous waste building up in the blood.
• Do you remember the topic of immune system in I/GCSE Biology?
• The problem with kidney transplants is that they kidney is rejected by the person’s immune system and they begin to attack as it has foreign antigens. We say the organ has been rejected.
• There is a way to avoid this:

1. using a kidney from a close relative as they would have similar antigens.
2. The patient will need life-long medication to prevent the kidney being rejected. This suppresses the immune system so the patient may catch colds more easily.

And we're done with this topic! Well Done!

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Drafted by Alyssa (Biology)

References:

1. "Kidneys (Anatomy)", https://img.webmd.com/dtmcms/live/webmd/consumer_assets/site_images/articles/image_article_collections/anatomy_pages/Kidney2.jpg
2. "File:Hemodialysis-en.svg", https://upload.wikimedia.org/wikipedia/commons/thumb/9/93/Hemodialysis-en.svg/654px-Hemodialysis-en.svg.png
3. "Kidney Transplant", https://5.imimg.com/data5/GJ/AV/HQ/SELLER-10502356/kidney-transplant-500x500.png