Why is excretion necessary In order for cells to stay alive they must continually intake water and other molecules The cells would continue to get bigger and bigger if they only took in molecules ID: 1036474
Download Presentation The PPT/PDF document "Excretory System Function and Parts" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
1. Excretory SystemFunction and Parts
2. Why is excretion necessary?In order for cells to stay alive, they must continually intake water and other molecules.The cells would continue to get bigger and bigger if they only took in moleculesThey must also export moleculesThese molecules may be important signaling molecules such as hormones, or they may be molecules of glucose on their way to other cells, or they may be waste products of cellular metabolism that cells need to dispose.
3. Waste ProductsCarbon dioxide – a waste product of cellular respiration is dumped into the blood stream and eventually removed by the lungsAmmonia (NH3) is removed through waterThis waste comes from the cells breakdown of old proteins It is also what makes bleach smell, so in high concentrations it is poisonous to the cells and must be removed
4. Removal of AmmoniaOnce excreted into the blood stream by cells, it is carried to the liver where it is converted from ammonia into urea which is much less toxicIt is then carried from the liver to the kidneys where it is removed
5. The Job of the KidneysThey are responsible for cleaning the blood by removing metabolic wastes, excess solutes, and excess water and excreting them as urineBesides removing urea, it also removes excess salts or glucose, the remnants of drugs (reason for urine tests), and excess water.
6. Regulation of Water LevelsIf the blood becomes too dilute or too concentrated with solutes, then it can interfere with normal cellular activity. Recall hypertonic, hypotonic & isotonic solutions!The kidneys are able to regulate water concentration in the blood by removing excess water if the blood is too dilute or conserving water in the blood if it is not dilute enough
7. The Hard-working KidneysThe two kidneys in the body receive between 1100 – 2000 liters (1160 – 2100 quarts or 500 gallons) of blood per day – about the volume of a car!Because the body has only about 5.6 liters of blood, your blood runs through the kidneys to be cleaned about once every four minutes.
8.
9. The Kidney
10. Formation of UrineIf there is too much water in the blood, then it is removed and put in urine.If there is not enough water in the blood, the kidneys will not remove it.If there is too much urea or other solutes in the blood, the kidneys will remove these excess solutes.By regulating solute numbers and water volume, the kidneys normally maintain homeostasis in blood solute concentration.
11. Factors that affect kidney functionAntidiuretic hormone (ADH) – prevents excess water loss from kidneysAlcohol – inhibits secretion of ADH = more urine volumeAldosterone – prevents excess loss of sodium and water from kidneysCaffeine – increases rate of salt and water loss from kidneysIncreased blood pressure – increase rate of water loss from kidneys.
12. SummaryStructures2 Kidneys2 Ureters1 Bladder1 UrethraFunctionsTo remove solid and liquid wastes from the blood stream.To reach an isotonic equilibrium in the blood.
13. When good organs go bad…This is a cross section of a normal kidneyThis is the outside of a kidney that has lost blood flow to the tan area & the cells have died.
14.
15. The excretory system eliminates nonsolid wastes from the body.Nonsolid wastes are eliminated through lungs, skin, and kidneys. Lungs exhale carbon dioxide and water vapor.Sweat glands in skin release excess water and salts.Kidneys filter and clean the blood to produce urine. skinlungskidneysuretersurinary bladderurethra
16. Kidneys have three basic functions in maintaining homeostasis.remove waste from bloodhelp to maintain electrolyte, pH, and fluid balances release key hormones
17. The kidneys help to maintain homeostasis by filtering the blood.Kidneys are a pair of bean-shaped organs.two layers: medulla and cortexfiltering units called nephrons renal artery and renal veincortexmedullarenal arteryrenal veinureter (to bladder)
18. Nephrons clean the blood and produce urine.4. Glomerulus-filters and cleans the blood5. Bowman’s Capsule-holds the filtrate, molecules are reabsorbed into the capillaries to balance the blood chemically6. Loop of Henle-Water is reabsorbed.7. Collecting ducts-collect urine from nephrons andsend it to the ureter.from bodyto bodyto bodyfrom other nephrons loop of Henle
19. Nephrons clean the blood and produce urine.Nephrons are the filtering units in the kidneys.They clean and rebalance the blood to produce urine.from bodyto bodyto bodyfrom other nephrons loop of Henle
20. Nephrons clean the blood in a three-step process.The first step is filtration of the blood.FILTRATIONWater,electrolytes,aminoacids,glucose,urea, and other small molecules diffuse out of the blood,creating the filtrate.1GlomerulusBowman’s capsule
21. The first step is filtration of the blood. The second step is reabsorption of materials.The third step is excretion of materials. from bodyto bodycollecting ductfrom other nephronsloop of HenleREABSORPTIONAs the filtrate enters the rest of the tubule ,most of the materials are reabsorbed into the blood.Materials not reabsorbed make up the urine,which flows into the loop of Henle.2EXCRETIONIn the loop of Henle,water can be reabsorbed one final time to reduce the volume of urine.The remaining urine flows into a collecting duct that leads to the ureter.3
22. Injury and disease can damage kidney functions.A kidney transplant can replaced damaged kidney. recipient and donor tissue must match drugs prevent tissue rejectionThe daughter and son in this photo donated a kidney and liver tissue to their mother.
23. Dialysis can be used to filter and clean the blood.