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Excretory System. Metabolic Waste Removal. Organs of Excretory System. Lungs – CO2 and water Skin - Sweat Kidneys – Urine Liver – detoxification of blood These organs work with other body systems to keep the body in homeostasis. Excretion.
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Excretory System Metabolic Waste Removal
Organs of Excretory System • Lungs – CO2 and water • Skin - Sweat • Kidneys – Urine • Liver – detoxification of blood • These organs work with other body systems to keep the body in homeostasis.
Excretion • Excretion – is the process by which waste and excess substances are removed from the body. • If wastes from metabolism (metabolic wastes) are not removed from the body, the body will die. • Metabolic wastes come from chemical reactions in the cells of the human body
Major Metabolic Wastes • Carbon Dioxide • Nitrogen compounds • Ammonia • Urea • Uric acid • Mineral Salts • Sodium chloride • Potassium sulfate • All of these wastes are poisonous to the body in high concentrations
Nitrogen wastes • Nitrogen wastes are a by product of protein metabolism. • Amino groups are turned into ammonia, which in turn is converted to urea, dumped into the blood and filtered out by the kidneys. • Ammonia is converted to urea, a compound the body can tolerate at higher concentrations than ammonia.
Role of the Liver • Removes harmful substances such as bacteria, certain drugs, and nitrogenous wastes from the blood • In the liver the substances are changed into inactive or less poisonous forms • Inactive substances (urea) are returned to the blood stream and filtered and excreted by the kidneys.
The Skin • The skin performs a number of different functions one of them is excretion of wastes. • In sweat there is a small amount of urea and salts. • Sweat 99% water 1% Urea and Salts
Lungs • Excrete CO2 and Water • The end products of cellular respiration
Urinary System • Waste is filtered from the blood and collected as urine in each kidney. • Urine leaves the kidneys by ureters, and collects in the bladder. • The bladder can distend to store urine that eventually leaves through the urethra • The urinary system: • Kidneys • Ureters • Bladder • urethra
Urinary tract Kidneys Ureters Bladder Urethra Prostate Male Female
Kidneys • Bean shaped organs that are about 10cm long • Main Functions: • Remove wastes of cellular metabolism (metabolic waste) • Regulate the concentrations of the substances in the blood
Structure of the Kidneys • Kidney is made up of 3 parts • Cortex – outer part • Medulla – middle part • Pelvis – inner part • Blood is filtered in the cortex • Collecting ducts extend through the medulla • The filtered substances, called the filtrate, collect in the pelvis which are connected to the ureter
Nephrons • MOST important job of the kidney is to filter waste from blood • The filtering is done by the nephron. • There are about 1.25 million nephrons in each kidney
Components of The Nephron • Glomerulus: Arteriole blood is filtered under high pressure. • Bowman's Capsule: surrounds the glomerulus and collects the filtrate
Component of Nephrons Continued • Proximal Convoluted Tubule • Loop of Henle • Distal Convoluted Tubule • All of these nephron structures aid in the reabsorption of materials needed for the body.
The Nephron Function • The nephron consists of a ball of blood capillaries called the glomerulus • Blood flows into the kidney through the renal artery, which branches into capillaries associated with the glomerulus.
The Nephron Function Continued • Arterial pressure causes water and solutes from the blood to filter into the Bowmans Capsule which surrounds the glomerulus • The Filtrate flows through the proximal convoluted tubule, loop of Henle, and then into the distal convoluted tubule. • The distal tubule empties into a collecting duct. Which carries urine to the pelvis of the Kidney
The nephron has three functions: • Glomerular filtration of water and solutes from the blood. • Tubular reabsorption of water and conserved molecules back into the blood. • Excretion of urine from collecting tubes
WOW that’s a big filter • Nephrons filter 125 ml of body fluid per minute; filtering the entire body fluid component 16 times each day. • In a 24 hour period nephrons produce 180 liters of filtrate, of which 178.5 (99%) liters are reabsorbed. • The remaining 1.5 liters forms urine.
Disruption of Kidney Function • Infection, environmental toxins such as mercury, and genetic disease can have devastating results by causing disruption of kidney function. Many kidney problems can be treated by dialysis, where a machine acts as a kidney. Kidney transplants are an alternative to dialysis.