Presentation on theme: "Kidney and kidney dialysis revision"— Presentation transcript:
1Kidney and kidney dialysis revision B3 biology. Mrs Carpenter
2Outcomes (pupils will be able to:) TITLE: Photosynthesis - making the linksObjectives:To revise how the kidneys produce urine – grade BTo 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 AKEY WORDS:nephronureaultra-filtrationselective reabsorptionosmosisactive uptakekidneybladderureterconcentration gradientcapillaryglomerulusloop of Henlecollecting ductconvolutedsurface areamitochondriaOutcomes (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.
14How does the kidney work? Boardworks GCSE Separate Sciences 2009The KidneysHow does the kidney work?Teacher notesStage 1: Filtration occurs as an increased blood pressure forces smaller substances through the capillary wall into the Bowman’s capsule. The glomerulus is a ball of blood vesselsStage 2: In the first coiled tubule (proximal convoluted tubule) most reabsorption is by active transport. The cells of the first coiled tubule are packed with mitochondria, and have large brush borders to increase the surface area for reasborption.Stage 3 & 4: Substances move out of the loop on Henle by passive diffusion. The cells of the loop of Henle are thin, with no brush border and relatively few mitochondria.Stage 5: The collecting duct carries water to the ureter.
15ADH – Anti Diuretic Hormone Controls osmoregulationIt 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.
17Regulating water content Boardworks GCSE Separate Sciences 2009The KidneysRegulating water content
18Useful you tube clips on the kidney Renal Anatomy 1 - Kidney – YouTubeRenal Anatomy 2 - Nephron – YouTube
19Task - Can you now answer these questions? What causes the contents of the blood to leave the capillary and enter the nephron?By which process does selective re-absorption usually happen?What would you expect to find in a person’s urine?Which substances from the blood would you not expect to find in a person’s urine. Justify your answer.Describe what is meant by ‘selective reabsorption’.Why is it important to control the concentration of water in the blood?Cells in the kidney contain a large number of mitochondria. Use your knowledge of mitochondria to explain why.Suggest a reason why red blood cells and large proteins do not leave the capillary at the glomerulus.
20Nephron AnswersWhat causes the contents of the blood to leave the capillary and enter the nephron?By which process does selective re-absorption usually happen?What would you expect to find in a person’s urine?Which substances from the blood would you not expect to find in a person’s urine. Justify your answer.Describe what is meant by ‘selective reabsorption’.Why is it important to control the concentration of water in the blood?Cells in the kidney contain a large number of mitochondria. Use your knowledge of mitochondria to explain why.Suggest a reason why red blood cells and large proteins do not leave the capillary at the glomerulus.
22Kidney failureIf 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.
23DialysisTreatment by dialysis restores the concentrations of dissolved substances in the blood to normal levels and has to be carried out at regular intervals.
24Kidney dialysis process 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.
28In 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)
29Clip from my-gcsescience.com Kidney Transplant vs Dialysis (10 mins) – My GCSE Science
37To prevent rejection of the transplanted kidney: 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 usedthe recipient is treated with drugs that suppress the immune system – immuno-supressants
38Advantages over dialysis Normal kidney function – no build up of toxins like ureaPrevents high blood pressureTransplant is cheaper in the long runTransplant does not result in blood clots but there is a risk from dialysisThe anti-coagulants used in dialysis are not used in transplant – these may mean blood doesn’t clot properlyInfection risk in dialysisDon’t need to restrict diet or fluid intake after transplant but you do on dialysisLess social issues
39Disadvantages over dialysis RejectionTissue match needed so may not be availableImmuno-suppressants mean you may be vulnerable to other infectionsRisks associated with an operation
40Task – Evaluate the processes of kidney transplantation and kidney dialysis
41How do you now feel about this topic? Hunky dory, fine and dandy ma’amMiddling – still a bit confused (it’s my hormones, miss)!Not a hope, lady!