JH-KEADLE The Excretory System

Organs of the Excretory System sweat glands lungs

The Excretory System Functions The excretory system collects wastes produced by cells and removes them from the body Urea (waste from breakdown of protein) helps maintain homeostasis by maintaining water balance and eliminating liquid waste

Organs of the Excretory System kidneys – major organs of the excretory system that filters blood and eliminates urea, excess water, and other wastes

Organs of the Excretory System

Organs of the Excretory System ureters – two narrow tubes that urine flows through to get to the bladder

Organs of the Excretory System urinary bladder – sac-like, muscular organ that stores urine

Organs of the Excretory System urethra – tube that urine travels to leave the body

The Filtering Process Every drop of blood in your body passes through the kidneys and is filtered 300 times a day nephrons – tiny structures that filter blood in the kidneys

Filtering Out Waste After entering the kidneys, blood flows through smaller and smaller arteries The blood eventually reaches a cluster of capillaries called nephrons In the nephron, urea, glucose, other chemicals, and some water move out of the blood and into the nephron

Filtering Out Waste Blood cells and proteins stay in the capillaries Glucose, water, and small amounts of other substances are reabsorbed into the blood stream Urea and other wastes stay in the nephrons

Filtering Out Waste The liquid left in the tube is urine The urine moves down the ureters and into the bladder When the bladder is full, you feel the urge to urinate

Filtering Summary 1. both wastes and needed materials are filtered out of the blood 2. the needed material is returned to the blood 3. the waste is eliminated in the urine

Analyzing Urine Some medical problems can be found by testing urine Glucose – diabetes Protein – kidney failure Drug residue – drug abuse

Other Organs of Excretion There are other organs in our body that can excrete substances Lungs – carbon dioxide and water Skin – sweat, water, some chemicals Liver – breaks down molecules, recycles hemoglobin and turns it into bile

Body systems that work with the respiratory system; Depends on the circulatory system to move the waste from the cell and deliver it to the kidneys, the respiratory system to remove carbon dioxide and the integumentary system to remove salts as sweat

Comparing Cells to Body What cell organelle helps to break down waste? lysosomes What cell organelle packages waste? golgi body