Excretory Systems

Excretion Secrete (get rid of) waste from the body –Way of maintaining homeostasis (balance) in the body HOMEOSTASISHOMEOSTASIS Waste

Organs of Excretion Lungs Skin Liver Waste: Waste: Urine

The Kidney Purpose: Filter wastes from blood and keep useful nutrients Waste products –During processing: nitrogen from broken down amino acids –Final waste product: Urine

Nephrons 1.Impurities of blood are filtered out 2. Wastes are collected 3. Purified blood returns to circulation

Pathway 1.Filtrate in blood enters through the renal artery –Contains waste (high concentration of nitrogen) and high concentration of salt

Pathway 2. Glomerulus Ball of capillaries within the Bowman’s Capsule –Fluid and soluble materials (i.e. glucose & amino acids) filter out of the blood into the Bowman’s capsule –Resulting fluid called filtrate

Pathway 3.Loop of Henle -Glucose is moved to descending tubule through active transport -Amino acids moved through passive transport -Wastes and useful materials are directly exchanged between tiny tubes and surrounding capillaries

Pathway 4a. Renal Vein –Blood is cleansed with proper water and salt balance 4b. Collecting Duct –Collects wastes called urine Contains –Greater concentrations of urea (N, H, O, C) –Very little water –No glucose or amino acids

Pathway: Ureter 5.Ureter -Moves urine to the bladder from the kidney -Urine contains high concentration of urea

Pathway 6. Bladder -Stores urine 7.Urethra - Moves urine out of the body

Pathway Summary

MalfunctionCauseSymptom High amount of nitrogen wastes Urine darker than normal Kidney Damage Caused by - Diabetes Glucose in urine (water follows glucose) Increased frequency of urination Dehydration

Malfunctions: Cont’d Kidney Stones Cause: Calcium, Magnesium, Uric Acid, Salt form together Symptoms: Intense lower back pain, blood in urine Gout Cause: Uric acid crystallizes and is deposited into the joints Diet, genetic disposition Symptoms: Joint pain Fever

Malfunctions: Cont’d Urinary Tract Infection Cause –Bacteria enter into the ureter –Ureter becomes inflamed Symptoms –Frequent painful urination

Malfunctions: Cont’d Hepatitis Cause: Virus Inflammation of the liver Symptoms: Jaundiced

Dialysis Machine that removes wastes from the blood –Go 3 times a week –Takes 2-3 hours each time