The Human Body: The Excretory System Textbook Chapter 34 Review Topic 1

Function Removes toxins and wastes which build up in the body as a result of metabolism Regulates the amount of fluid and salts in the body and maintains pH of the blood Helps regulate homeostasis

Parts Lungs Excretes carbon dioxide Skin Excretes water and salts contained in sweat Kidneys Major excretory organ in the body

Kidneys Bean-shaped Filters out wastes, water and salts from the blood Two regions Renal cortex ~ outer region Renal medulla ~ inner region

Contains microscopic tubules and blood vessels Renal pelvis ~ center of kidney where these filters are found

Nephron filtration Each kidney has 1 million filtering units called nephrons Blood enters each Nephron through a long tube surrounded by capillaries called a glomerulus Surrounded by the Bowman’s capsule

Renal artery transports nutrients and wastes to the kidney Branches into smaller blood vessels forming the glomerulus Blood vessel walls are thin and under high pressure

Urea ~ nitrogenous waste product containing water and substances dissolved in water Pushed through capillary walls into the Bowman’s capsule Red blood cells and proteins are too large and remain in the blood stream

Reabsorption/formation of urine Filtrate collects in the Bowman’s capsule and flows through renal tubules (loop of Henle and collecting tubule) Most water and useful substances (ex. glucose, minerals) are reabsorbed back into blood stream (reabsorption)

Excess fluids and toxic substances are collected to form urine Leaves the kidneys through ducts called ureters Urine is stored in the urinary bladder Exits the body through the urethra

Each kidney filters 180 L of blood a day in adults to produce 1.5 L of urine Process requires large amounts of energy Use 20-25% of your body’s oxygen intake for their internal energy requirements! Controls pH balance by absorbing or filtering out acids or bases to regulate pH of the blood

Urinary System BrainPop

Kidney Disorders Infections Start as bladder infections which spread to kidney Fever, chills, mid-/lower-back pain Can be caused by blockages If untreated, kidneys can scar causing a loss in function Can be treated with antibiotics

Nephritis Inflammation (painful swelling) of the glomeruli Cause by blockages Blood in urine, swelling of body tissues, protein in urine Can improve on its own but may require a special diet or prescription drugs to treat the infection

Kidney Stones Crystallized solid (calcium compound) which forms in the kidney Small stones can be passed out in urine Larger stones are broken up using ultrasonic sound waves or removed using surgery

Diabetes/High Blood Pressure Causes reduced kidney function or kidney failure Illegal/Prescription Drugs Can cause kidney damage

Treatments Dialysis An artificial kidney machine filters out wastes and toxins from a patient’s blood

Two types Blood is passed through the machine temporarily to be filtered and cleaned, then returned (3-4 hours/3 days week) Membrane lining the abdomen acts as an artificial kidney by injecting it with a special fluid through a small tube attached to the patients body to collect draining wastes ( min/daily)