removal of wastes


Post on 23-Feb-2016




0 download

Embed Size (px)


REMOVAL OF WASTES. Learning Objectives. EXCRETION Recall the origin of CO 2 and O 2 as waste products of metabolism. Recall that the lungs, kidneys and skin are organs of excretion. Understand how the kidney carries out its roles of excretion. STRUCTURE OF URINARY SYSTEM AND THE KIDNEYS - PowerPoint PPT Presentation



REMOVAL OF WASTES1Learning ObjectivesEXCRETIONRecall the origin of CO2 and O2 as waste products of metabolism.Recall that the lungs, kidneys and skin are organs of excretion.Understand how the kidney carries out its roles of excretion.STRUCTURE OF URINARY SYSTEM AND THE KIDNEYSDescribe the structure of the urinary system.Describe the structure of a nephron.2ExcretionSome products of chemical reactions that occur within cells are poisonous and so must be removed.Excretion is the removal from the body of:The ______ products of its chemical reactions.The excess ______ and _____ taken in with the diet.Spent __________.D____.Any other foreign substances taken into the alimentary canal and absorbed by the blood.

wastewatersaltshormonesrugs3Excretory Organs Lungs_________ (the breakdown of glucose) produces ______ ______, which is carried away from the cells by the _____, and removed in the _____.The loss of water vapour from the lungs is unavoidable, and not a method of controlling the water content of the body.carbon dioxide bloodlungsRespiration4Excretory Organs SkinWhen we ______, we expel water, sodium chloride (____) and traces of urea.The skin is not a true example of an excretory organ though, as sweating is a response to a rise in temperature, not a change in the blood composition.sweatsalt5Excretory Organs KidneysExcess amino acids are broken down in the ____, to form glycogen and ____. The ____ is removed from tissues by the _____, and expelled by the kidneys.Urea and uric acid from the breakdown of protein contain nitrogen nitrogenous waste products.When hormones have done their job, they are modified in the liver and excreted._____ is the watery solution excreted by the kidneys which contains the nitrogenous waste products, excess salts and ______, drugs, toxins and spent hormones.

bloodureaureaUrinewaterliverLiver detoxifies harmful chemicals eg alcohol. Breaks down proteins to release ammonia.


Highly toxic nitrogenous waste.In mammals, amphibians and shakes we covert this to less toxic compound called urea and remove it via urine use energy and water

In most aquatic animals it can pass in the form it is across fills and dissolves into surrounding water.

In birds, insects many reptiles covert to non toxic form uric acid (non soluble, white solid) which requires lots of energy to do but reduced water loss.

6Structure of the KidneysTwo kidneys.Fairly solid, oval-shaped structures.Red-brown in colour.Enclosed in a transparent membrane.Attached to the back of the abdominal cavity.Renal artery branches off from the aorta and supplies the kidneys with oxygenated blood.The renal vein takes deoxygenated blood back to the vena cava.7Ureter a tube that connects each kidney to the bladder.Renal tubules many capillaries and tiny tubes in the kidney tissue, held together with connective tissue.Cortex dark outer region of kidney.Medulla lighter, inner zone.Pelvis space where the ureter joins the kidney.Glomerulus a divided and coiled capillary leading from each arteriole. The renal artery divides up into many arterioles and capillaries in the cortex.8Renal capsule (Bowmans capsule) a cup-shaped organ almost entirely surrounding the glomerulus. It is a smooth semi-transparent membrane. The renal capsule leads to the renal tubule.Collecting duct the coiled and looped renal tubule leads to the collecting duct. The collecting duct passes through the medulla and opens into the pelvis.Nephron a single glomerulus with its renal capsule, renal tubule and capillaries.There are thousands of glomeruli in the cortex, and the surface area of their capillaries is very large.









A NEPHRONRenal capsule (Bowmans)Glomerulus(capillaries)Renal artery (blood with waste)Renal vein (blood without waste)Loop of HenleRenal tubuleCollecting duct17YOUR TURNLABEL KIDNEY AND NEPHRONWORKSHEET : 19: matchmaker removing wastesQUESTIONS

Learning ObjectivesULTRAFILTRATIONDescribe ultrafiltration in the Bowmans capsule and the composition of the glomerular filtrate.SELECTIVE REABSORPTIONUnderstand that water is reabsorbed into the blood from the collecting duct.Understand that selective reabsorption of glucose occurs at the proximal convoluted tubule.19UltrafiltrationThe process by which fluid is filtered out of the blood by the glomerulus into the Bowmans capsule.This allows the body to remove waste products and regulate the amount of water in the blood.The blood pressure in the glomerulus is very high.This causes small molecules like water with dissolved salts, glucose, urea and uric acid to leak out of the blood plasma through the capillary walls.Red blood cells and proteins are too large to filter out (similar to tissue fluid).20Selective ReabsorptionThis filtrate from the glomerulus (glomerular filtrate) collects in Bowmans capsule and trickles down to the renal tubule and collecting duct.The surrounding capillaries absorb back into the blood those substances that the body needs:All the glucose (occurs in the proximal convoluted tubule)Much of the waterSome of the saltsAll other substances not needed by the body (rest of salts, urea, uric acid, water) continue down the renal tubule into the pelvis, then onto the ureter to bladder.99% of the primary filtrate (but half or less of the urea) undergoes reabsorptionGlucose and amino acids reabsorbed by active transport against concentration gradient, also salts and sodium chloride which consumes a lot of energyWater absorbed via osmotic gradient.21Learning ObjectivesOSMOREGULATION AND ADHUnderstand how the kidney carries out its roles of osmoregulation.Describe the role of ADH in regulating the water content of the blood.

22OsmoregulationThe regulatory processes that keep the blood at a steady concentration.The body gains and loses a lot of water all the time.How/where?The kidneys keep the concentration of body fluids within very narrow limits.If the blood concentration is too dilute (too much water):Less water is reabsorbed by the renal tubulesSo more enters the bladderSo a large volume of dilute urine is produced.23If the blood is too concentrated, more water is reabsorbed from the renal tubules.If the body is short of water (e.g. after sweating profusely), only a small amount of urine is produced.The thirst centre in the brain is stimulated, to return the blood to its correct concentration.Because these processes regulate the osmotic strength of the blood, it is called osmoregulation.It is an example of homeostasis keeping the composition of the tissue fluid within narrow limits.24ADH (anti-diuretic hormone)Detected by the hypothalamus in the brain, and produced by the pituitary gland.ADH is secreted into the blood if the concentration is too high.ADH causes the kidneys to reabsorb more water from the glomerular filtrate back into the blood.The urine then becomes more concentrated, and less water is lost from the blood.The opposite will happen if the blood passing through the brain is too dilute.Alcohol:When large amounts of alcohol are consumed, large volume of dilute urine is produced. Excessive alcohol results in a dcrease in the release of ADH, from the pituitary gland. ADH necessary for the production of concentrated urine. A decrease in ADH levels then results in increase in urine production. Large amounts of water are excreted in dilute urine so therefore also causes dehydration. 25


View more >