Excretion in Humans Ch 11 for Karishma.pptx

Notes in slides for Class 11

1. Excretion in humans Chapter 11

2. Waste Organ to excrete Ammonia Kidneys Urea Kidneys Uric Acid Kidneys Excess water Kidneys, Skin Minerals Kidneys, Skin CO2 Lungs Bile pigments Liver Lactic Acid Liver O 2 Metabolic waste products and toxic substances are excretory products. Excretion is the process by which metabolic waste products and toxic substances are removed by the body of an organism.

3. Excretion is the process by which metabolic waste products and toxic substances are removed by the body of an organism. 5 5 5 2 2 What are nitrogenous waste products?

4. Kidneys are bean shaped organs. Average size of human Kidney is 10 to 13 cm long and 5 to 7 cm wide. The human urinary system consist of a pair of Kidneys, a pair of ureters, a urinary bladder and urethra. 5 5 5 5 2 5 5

5. Organ Hilus Is an elastic muscular bag to collect and store urine. Is the depressed portion of concave surface of kidney, where renal artery, renal vein and nerves are connected. Ureter Is located at the bottom of the bladder and control urination. Signals from brain activate these muscles to induce urination. Is a narrow tube that connects kidney to urinary bladder to transfer urine from kidney. Urinary Bladder Is the duct through which urine released from the bladder to outside of the body. Is an elastic muscular bag to collect and store urine. Urethra Is a narrow tube that connects kidney to urinary bladder to transfer urine from kidney. Is the duct through which urine released from the bladder to outside of the body. Sphincter Muscle Is the depressed portion of concave surface of kidney, where renal artery, renal vein and nerves are connected. Is located at the bottom of the bladder and control urination. Signals from brain activate these muscles to induce urination.

6. Organ Bowman’s Capsule Is the portion of tubule connect with multiple distal convoluted tubules which in to medulla region and further open in to renal pelvis. Is a cup-like structure at the beginning of nephron. Proximal convoluted tubule Is the U shaped portion of tubule that extends in pyramid from cortex region to medulla and back in to cortex. Is coiled tubule after capsule. Loop of Henl é Is a cup-like structure at the beginning of nephron. Is the U shaped portion of tubule that extends in pyramid from cortex region to medulla and back in to cortex. Distal convoluted tubule Is coiled tubule after capsule. Is the portion tubule that coiled again in cortex Collecting duct Is the portion tubule that coiled again in cortex . Is the portion of tubule connect with multiple distal convoluted tubules which in to medulla region and further open in to renal pelvis.

7. Blood enters the kidney by the renal artery, which branches out in to arterioles. Each arteriole further branches into a mass of blood capillaries in the bowman’s capsule. Blood leaving the glomerulus enters blood capillaries surrounding nephron. These blood capillaries then unit for form venules , which in turn join to form a branch of the renal vein. Blood enters the kidney by the renal artery, which branches out in to arterioles. Each arteriole further branches into a mass of blood capillaries in the bowman’s capsule. Blood leaving the glomerulus enters blood capillaries surrounding nephron. These blood capillaries then unit for form venules , which in turn join to form a branch of the renal vein. Blood enters the kidney by the renal artery, which branches out in to arterioles. Each arteriole further branches into a mass of blood capillaries in the bowman’s capsule. Blood leaving the glomerulus enters blood capillaries surrounding nephron. These blood capillaries then unit for form venules , which in turn join to form a branch of the renal vein.

8. Two main processes in each nephron Ultrafiltration of small molecules from the blood Selective reabsorption of useful substances

9. Ultrafiltration of small molecules from the blood Hydrostatic blood pressure (or high blood pressure) provides the main force required for the filtration. Basement membrane is partial (Semi) permeable membrane of glomerular blood capillaries. Acts like a very fine filter allows only water and very small molecules to pass through. Filtered: Glucose, Aminoacids , mineral salts and waste products Retained: Blood cells, platelets, proteins, fat and other large molecules. Filtrate (120cm 3 per minute) Useful molecules are needed for the body Large amount of water loss will dehydrate body

10. Selective reabsorption

11. Water 96.0g/100g Mineral salts (Mainly NaCl ) 1.8g /100g Urea 2.0 g /100g Other Nitrogenous Substances 0.2g /100g Normal Healthy Person Protein rich diet will increase Urea in urine Excess water or liquid consumption will increase water potential of blood, thus will increase the water content of urine. High intake of salty food will result in excess salt in urine Certain metabolic disorder (diseases) may also cause abnormal composition of urine. Example: excess amount of Glucose in urine of a person with diabetes mellitus. Composition of urine

12. Urine formation involves ultrafiltration and selective reabsorption useful substances. Ultrafiltration occurs through the basement membrane in the renal corpuscles because of the high hydrostatic pressure in the glomeruli. Useful substances in the filtrate in the nephron are taken back in the bloodstream by selective reabsorption. In a healthy person, urine normally consists of water, mineral salts, urea and other nitrogenous waste products. This composition may change depending on a persons diet and health. Guess the missing words

13. Osmoregulation Water potential of the blood depends on the amount of water and mineral salts in the plasma. Water potential of the blood has to be kept relatively constant. Water will enter in to cells if blood plasma is too diluted (too much of water): Cells will burst . Less water in plasma makes blood concentrated and water from cells move out in to plasma. Cells can not do their normal metabolic function and eventually make permanent damage of organs. The amount of water in the blood is controlled by antidiuretic hormone ( ADH ). ADH is produced by pituitary gland situated in hypothalamus of brain

14. Osmoregulation

15. Common causes of kidney failure High blood pressure Diabetes Alcohol abuse Physical dame due to severe accidents Complications as a result of major surgery. When one kidney fails, the person still can lead a normal life with the other kidney. But when both kidney fail, person could die without medical intervention. Kidney transplant Dialysis using dialysis machine Kidney failure

16. The dialysis fluid contains the same concentration of essential substances as healthy blood. This ensures that essential substances (such as glucose, amino acids and mineral salts) do not diffuse out of the blood and into the dialysis fluid. Furthermore, if the patient's blood lacks these essential substances, these substances will diffuse from the dialysis fluid into the blood.   The dialysis fluid does not contain metabolic waste products This sets up a concentration gradient that allows waste products such as urea, uric acid, creatinine, and excess water and mineral salts, to diffuse out of the tubing into the dialysis fluid. The waste products are removed from the blood. This maintains the correct solute composition and water potential of the blood . The tubing in the machine is narrow, long and coiled This increases the surface area to volume ratio which helps to speed up the rate of exchange of substances between the patient's blood and the dialysis fluid.   The direction of the blood flow is opposite to the flow of the dialysis fluid. This maintains the concentration gradient for the removal of waste products .