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The Body Systems. The Excretory System. Organs of Excretion. EXCRETION: the process by which the body collects and removes wastes Liver Converts impurities and poisons to less harmful substances Forms urea to be transported safely to kidneys via the blood
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The Body Systems The Excretory System
Organs of Excretion • EXCRETION: the process by which the body collects and removes wastes • Liver • Converts impurities and poisons to less harmful substances • Forms urea to be transported safely to kidneys via the blood • Some things processed become a part of bile
Organs of Excretion • Lungs and Skin • Lungs remove carbon dioxide (and some water) when you exhale • Sweat glands in skin • Secrete water and urea in perspiration
Organs of Excretion • Kidneys • 2 – each the size of a fist • Filter urea and other wastes from blood • Wastes eliminated in urine • Main organs involved in water balance • Brain sends signals in the form of hormones to tell the kidneys to release more or less water • http://www.youtube.com/watch?v=4-15JUVxAm8
Filtration of Wastes • Each kidney contains about 1 million NEPHRONS – remove waste, produce urine • 2 Stages: needed materials and wastes removed from blood; needed materials returned to blood
Filtration of Wastes • Filtering Out Wastes • Blood enters kidneys, reaches GLOMERULUS - cluster of blood cells in a nephron • Everything filtered (urea, salts, glucose, water) and into capsule surrounding • Formation of Urine • Glucose and water filtered into blood • Other wastes stay in tube – fluid that remains is urine
Keeping Healthy • Drink Water • Dilutes waste products • Treat Infections • Urinary Tract Infections (UTI’s) – bacterial • When bacteria from digestive system comes in contact with the urethra • Frequent, painful urination; blood in urine • Prompt treatment with antibiotics – prevent from spreading to kidneys
Keeping Healthy • Preventing Kidney Stones • Pebble-like masses, most commonly calcium • VERY PAINFUL, but most usually will eventually pass • Drink plenty of water and low-sodium
Keeping Healthy • Treating Kidney Failure • Damaged from injury, diabetes, high BP • Unable to remove wastes and excess fluids • DIALYSIS: Machine filters wastes from blood; tubes run from machine, to body, and back to machine where wastes are eliminated; 3 times a week for 3-5 hours
Keeping Healthy • Treating Kidney Failure • Kidney Transplant • Damaged kidney replaced with a healthy kidney