The Excretory System Excretion ● The process by which the body collects and removes wastes ● Several organs involved in excretion ○ Minor Role ■ Liver ■ Lungs ■ Skin ○ Major Role ■ Kidneys ■ Large Intestine ■ Bladder ■ Urethra Liver ● Converts impurities and poisons in the body to less harmful substances ● Makes urea ○ Substance formed from a waste product of protein breakdown ● Some of these substances become a part of bile ● After aiding fat digestion in the small intestine, bile is eliminated from the body during stool Lungs and Skin ● Lungs ○ When you exhale lungs remove ■ Carbon Dioxide ■ Some water ○ Why can you see your breathe when it's cold outside? ● Skin ○ Sweat glands ■ Water ■ Urea Kidneys ● 2 kidneys, about the size of your fist ● Major organ of urinary system ○ Urine- Watery fluid produced by kidneys ● Filter urea and other wastes from blood ● Wastes are eliminated through urine ● Maintain water balance ○ Hot day (sweating) and little water consumption ■ Kidneys do not release much water ○ Cool day (no sweat) and drink plenty of water ■ Kidneys release more water ● Homeostasis ○ Stable internal environment The Urinary System ● Kidney ○ The kidneys produce urine by filtering urea and other wastes from the blood. ● Ureter ○ One ureter extends from each kidney. The ureters carry urine from the kidneys to the bladder. ● Bladder ○ The bladder is a saclike muscular organ that stores urine. ● Urethra ○ Urine travels through the urethra as it exits the body. Filtration of Wastes ● Nephrons ○ Tiny filtering units that remove wastes and produce urine ■ First both needed materials and wastes are filtered from the blood ■ Then, the needed materials are returned to the blood, and wastes are eliminated Nephron ● Blood flows from an artery into a nephron ● In the glomerulus, urea, water, glucose and other materials are filtered from the blood. ● Materials pass through the long twisting tube, surrounded by blood vessels. ● In the tube, the water and glucose are reabsorbed into your blood. ● Most of the urea and other waste stay in the tube. ● Liquid remaining in the tube is urine. Keeping Healthy ● Drinking plenty of water ○ Can dilute harmful substances ● Medical Checkups ○ Urine Tests ■ Glucose - diabetes ■ Protein - High blood pressure ● Urinary Tract Infections (UTI) ○ Bacterial infection of the urethra or bladder ○ Bacteria from digestive system come in contact with the urethra ■ Frequent painful urination ■ Blood in urine ● Prompt treatment with antibiotics ● Can lead to kidney damage Kidney Disease ● Kidney Stones ○ Pebble like masses that form in the kidney ○ Very painful ○ Most pass through excretory system on own ○ May have to have stone shattered ○ Low-sodium diet to reduce risk ● Kidney Failure ○ Result of injury, diabetes, or high blood pressure ○ Kidneys unable to remove excess waste and fluid ■ Kidney Dialysis ● Machine is used to filter waste and excess fluid from blood ● Tubes carry blood from the body through the machine ● Performed 3 times a week for 3-5 hours ■ Kidney Transplant ● Patients damaged kidney is replaced with a healthy kidney from another person.