Presentation on theme: "Kidney and kidney dialysis revision B3 biology. Mrs Carpenter."— Presentation transcript:
Kidney and kidney dialysis revision B3 biology. Mrs Carpenter
TITLE: Photosynthesis - making the links Objectives: To revise how the kidneys produce urine – grade B To revise the explanation of the processes of ultra- filtration and selective reabsorption and link these to nephron structures – grade A/A* To revise kidney dialysis and be able to compare and contrast its function with the kidney - grade B – and be able to evaluate giving a detailed explanation in terms of diffusion and concentration gradients – grade A/A* To revise the adv and disadv of kidney transplantation – grade A KEY WORDS : nephron urea ultra-filtration selective reabsorption osmosis active uptake kidney bladder ureter concentration gradient capillary glomerulus loop of Henle collecting duct convoluted surface area mitochondria Outcomes (pupils will be able to:) Label and annotate a kidney diagram and be able to explain how urine is formed in the nephron. Be able to explain how kidney dialysis works and be able to compare it to normal kidney function. Be able to evaluate kidney transplantation and kidney dialysis.
Collecting duct leads onto the ureter Glomerulus Bowman’s capsule PCT DCT Loop of Henle
12 glomerulus branch of renal artery Bowman’s capsule branch of renal vein loop DCT PCT collecting duct capillaries
How does the kidney work?
ADH – Anti Diuretic Hormone Controls osmoregulation It is a hormone: a chemical messenger that travels in the blood to activate target cells. Hormones can act for a long period of time (compared to the nervous system) and they act in a general way ie if a cell has the necessary receptor it will be affected by the hormone.
Controlling water content
Regulating water content
Useful you tube clips on the kidney Renal Anatomy 1 - Kidney – YouTube Renal Anatomy 2 - Nephron – YouTube
Task - Can you now answer these questions? 1.What causes the contents of the blood to leave the capillary and enter the nephron? 2.By which process does selective re-absorption usually happen? 3.What would you expect to find in a person’s urine? 4.Which substances from the blood would you not expect to find in a person’s urine. Justify your answer. 5.Describe what is meant by ‘selective reabsorption’. 6.Why is it important to control the concentration of water in the blood? 7.Cells in the kidney contain a large number of mitochondria. Use your knowledge of mitochondria to explain why. 8.Suggest a reason why red blood cells and large proteins do not leave the capillary at the glomerulus.
Nephron Answers 1.What causes the contents of the blood to leave the capillary and enter the nephron? 2.By which process does selective re-absorption usually happen? 3.What would you expect to find in a person’s urine? 4.Which substances from the blood would you not expect to find in a person’s urine. Justify your answer. 5.Describe what is meant by ‘selective reabsorption’. 6.Why is it important to control the concentration of water in the blood? 7.Cells in the kidney contain a large number of mitochondria. Use your knowledge of mitochondria to explain why. 8.Suggest a reason why red blood cells and large proteins do not leave the capillary at the glomerulus.
Kidney transplant v kidney dialysis
Kidney failure If kidneys fail, they will not be able to clear enough urea and salts and a person will need to have their blood artificially filtered to remove it…otherwise the water balance of cells is destroyed and they may swell and burst due to OSMOSIS. Urea also poisons cells. The treatment is called dialysis and is done by a machine called a dialyser.
Dialysis Treatment by dialysis restores the concentrations of dissolved substances in the blood to normal levels and has to be carried out at regular intervals.
Blood enters machine from body (under pressure from radial artery). Pump (controls pressure and flow rate. Anticoagulant added to prevent clotting. Blood passes through dialysis membrane (equivalent to kidney nephrons). Bubble Trap removes any gas bubbles from blood. Blood is filtered then returned to the patient's radial vein. Kidney dialysis process
In a dialysis machine a person’s blood flows between partially permeable membranes. The dialysis fluid contains the same concentration of useful substances as the blood. This ensures that glucose and useful mineral ions are not lost. (they are in equilibrium) Urea passes out from the blood into the dialysis fluid (dialysate) by diffusion (it moves from high to low)
Clip from my-gcsescience.com Kidney Transplant vs Dialysis (10 mins) – My GCSE Science Kidney Transplant vs Dialysis (10 mins) – My GCSE Science
Other clips DocMikeEvans w GCSE - kidneys - YouTube
Task. Explain the process of kidney dialysis.
Task. How is the process of kidney dialysis comparable to the functioning of the normal kidney?
Can you do this exam q now?
Being on dialysis interferes in a person’s every day life – needing 4 hours of dialysis 3 or 4 times a week – often in hospital ….. …. Or at home
Transplant As dialysis is very invasive into a person life, many people want to have a transplant. Organs come either from ‘living’ donors or dead organ donors.
In kidney transplants a diseased kidney is replaced with a healthy one from a donor. However, the donor kidney may be rejected by the immune system unless precautions are taken. Antigens are proteins on the surface of cells. The recipient’s antibodies may attack the antigens on the donor organ as they do not recognise them as part of the recipient’s body. To prevent rejection of the transplanted kidney: – a donor kidney with a ‘tissue-type’ similar to that of the recipient is used – the recipient is treated with drugs that suppress the immune system – immuno-supressants
Advantages over dialysis Normal kidney function – no build up of toxins like urea Prevents high blood pressure Transplant is cheaper in the long run Transplant does not result in blood clots but there is a risk from dialysis The anti-coagulants used in dialysis are not used in transplant – these may mean blood doesn’t clot properly Infection risk in dialysis Don’t need to restrict diet or fluid intake after transplant but you do on dialysis Less social issues
Disadvantages over dialysis Rejection Tissue match needed so may not be available Immuno-suppressants mean you may be vulnerable to other infections Risks associated with an operation
Task – Evaluate the processes of kidney transplantation and kidney dialysis
How do you now feel about this topic? Hunky dory, fine and dandy ma’am Middling – still a bit confused (it’s my hormones, miss)! Not a hope, lady!