Kidneys and Excretory System

How Urination works htmhttp://health.howstuffworks.com/adam htm

Excretion The process of excretion involves the removal of metabolic waste. If wastes build up in the body, they become toxic. There are 4 main organs that work to remove waste from the body.

Excretion con’t 1.The skin - removes waste heat, some urea, and other materials found in sweat 2. The lungs - removes C02 3. The large intestine - removes solid wastes of the digestive process 4. The kidneys - removes urea, uric acid, extra water and salts

Anterior View of the Urinary System

Posterior View of the Urinary System

Questions page List 3 main functions of the kidney. a. Eliminates wastes b. regulation of water balance - Also regulation of pH - Also regulates blood pressure and is involved in the production of red blood cells.

Questions page con’t 2. What is deamination and why is it an important process? -Deamination is the removal of the amino groups from a protein (organic compound) -Amino groups = 2 H + 1 N

Questions page con’t 2 con’t -Deamination occurs in the liver -Important to convert excess amino acids into carbohydrates and other nutrient compounds

Questions page con’t 3. How does the formation of urea prevent poisoning? - Deamination produces ammonia, a water soluble gas. - Ammonia is extremely toxic and cannot be stored in the body. - The liver combines two molecules of ammonia with carbon dioxide to form urea. - Urea is 1000 times less toxic than ammonia. -Animals can store urea for short periods of time in their bodies -Permits the controlled excretion of urine

Questions page State the function… Bowman’s capsule: The filtration of water and dissolved solutes happens as blood is forced from the glomerulus to the Bowmen’s capsule Proximal tubule: Selective reabsorption of nutrients from filtrates back into the blood Loop of Henle: Reabsorption of water and salt Distal Tubule: secretion of substances from the blood to the urine Collecting duct: Urine formation

The urethra is the only part of the urinary system that differs between males and females. It is longer in males.

Questions page con’t 5. List and describe the 3 processes involved in urine formation. a.Filtration – involves the movement of fluids from the Bowman’s capsule to the glomerulus. b.Reabsorption – involves the movement of fluids from the nephron into the interstitial fluid and eventually the capillary net. c.Secretion – involves the selective transport of fluids from the capillary net into the nephron.