Cells, tissues and organs All living organisms are made up of cells. Large numbers of cells group together to form tissue. Tissues can combine to form organs.

Kidney function The kidneys act as sieves. As blood passes through they filter out: Water Glucose Urea (waste) Ions (salt) Blood cells and large molecules, such as proteins, stay in the blood (they are too big to be filtered). Then the kidneys reabsorb what the body requires. The rest of the filtered chemicals go to the bladder to make up urine. A question you may like to ask about kidneys: Q. What do you think gets reabsorbed? A. Glucose (sugars) for respiration; as much water and salt as the body requires.

Kidney failure You have two kidneys, but you can manage with just one. But if both kidneys fail, urea (waste) rises and the body is poisoned. So if your kidneys fail, there are 2 options: Option 1: Dialysis You are attached to a kidney machine via a tube from a vein. Your blood flows into the machine, is cleansed, and returns to your body. You are attached for about 5 hours, 3 times per week. Option 2: A kidney transplant You have an operation to remove your failed kidney and replace it with a working kidney from a donor. One or both kidneys may need to be transplanted Questions you may like to ask about kidney failure: Q. How would you feel about being attached to a kidney machine?

Dialysis or transplant? Kidney dialysis works quite well, but is a time-consuming burden. Apart from taking drugs to stop their body rejecting the new kidney, someone with a successful transplant can lead a completely normal life. A transplant costs about £42,000 for the operation plus £6,500 a year in drugs and check-ups. BUT Dialysis isn’t cheap – about £23,000 per year, for life. Watch the film about Andrew Samuel waiting for a transplant Q: How long after a transplant would it be before the NHS starts saving money, compared to keeping the patient on dialysis? A: About two and a half years. Q: If a 20 year old has a kidney transplant and lives to 80, roughly how much money would the NHS save? A: Cost of dialysis: 60 years x £23,000 = £1,380,000. Cost of transplant: (60 years x £6,500) + £42,000 = £432,000. Saving: £948,000 – roughly one million pounds.

Where do the donor kidneys come from? A living person can donate one kidney. To donate a kidney (or any organ) after death, you have to have died in hospital – they have to be removed quickly. Most people die at home so there is a serious shortage of donor kidneys for transplant. There are around 7,000 people waiting for a kidney transplant. Around 2,000 kidney transplants are carried out annually and each year 2,000 more people go on the kidney transplant list Important: this topic needs to be handled with sensitivity. Please be aware that some students may have lost a friend or relative in tragic circumstances. If appropriate, this is a chance to talk about why it is so important for anyone who joins the Organ Donor Register to discuss their decision with their close family. Many organ donation opportunities are lost because next of kin are unaware of the deceased’s wish to donate, which places doctors in a very difficult position. Most donor kidneys come from patients who have died while on a ventilator following a severe brain injury. Q: Why do organs need to be removed from a dead person quickly? A: Organs are made of living tissue which will die if it is not supplied with oxygen and glucose for cell respiration.

Organ transplants After death, the following organs can be donated for organ transplant: kidneys heart liver lungs pancreas small bowel In life, some organs can be donated too: kidneys, because we can manage with just one. part of the liver, because it can regenerate (grow back) part of the lung part of the small bowel (small intestine) For a successful organ match, the donor and transplant patient ideally should have compatible: Blood group and Human Leukocyte Antigen type Some questions you may like to ask about organ transplants: Q. Why can’t we donate a heart in life? A. We only have one heart, which is essential to pumping blood around our bodies. Q. An organ transplant is most likely to be successful if the transplanted organ is from an identical twin. Why? An identical twin has the best genetic match, so blood type and tissue type will be most compatible. Q. Why might someone be willing to donate a kidney, or part of their liver, lungs or bowel, while they are alive? A. They can still enjoy a normal, healthy life and will have saved or vastly improved the life of someone else, who me be a close friend or relative.

Blood group Group A: Group B: Group AB: Group O: Can receive from: Can receive from Group A and Group O Can receive from Group B and Group O Can receive from all groups Can only receive from Group O Can donate to: Can donate to Group A and Group AB Can donate to Group B and Group AB Can donate to Group AB Can donate to all groups The key point for all pupils is that a transplant patient can only accept a donated kidney from somebody who belongs to a compatible blood group.

Matching donor organs to recipients – Human Leukocyte Antigen (HLA) tissue type A kidney donor needs to be a close HLA type match with the recipient. HLA type can make the difference between a patient’s body accepting or rejecting a donated organ. HLA type is defined by six principal pieces of protein: HLA antigens. Each newly discovered HLA antigen has been numbered. Doctors aim for at least a four HLA match between a donor and patient. Which of these donors is the best match for someone in need of a kidney transplant, with HLA numbers 2 3 6 9 10 13? Recipient 1: 2 6 7 10 11 13 Recipient 2: 3 6 8 9 11 12 Recipient 3: 2 6 9 10 12 13 Details of the HLA tissue type system fall outside most exam specifications, it’s just the principle that is required for the class activity that follows.