 Students will be able to:  Discuss the role of the excretory system in maintaining homeostasis  Identify and discuss the structure and function of the urinary system  Explain how the kidneys/nephrons filter blood and produce urine  Discuss how disruption of homeostasis affects urine production

 Excretory System  Urine  Urea  Kidneys  Nephrons  Bladder  Ureters  Urethra

 Excretion: removal of harmful metabolic waste  Urinary System: The kidneys remove urine a combination of urea, salts, and water

 1. Elimination  The removal of harmful wastes from the body  2. Regulation  Control and balance the of blood  water, pH, salts

 Major Organs  2 kidneys -  filters blood, produce urine  2 ureters -  Tubes that carry urine from kidney to urinary bladder  1 urinary bladder -  stores urine  1 urethra -  Tube that carries urine outside of the body

 Main excretory organ  Location  Made up of millions of filtering units called nephrons

 The functional unit of the kidney  Renal artery, renal vein, capillaries  1. Filters the blood  Proteins and red blood cells do not enter nephron  Everything else in blood enters nephron (salt, water, glucose, amino acids)

 2. Reabsorption in the renal tubule:  Water via Osmosis  Active Transport of glucose, salt, amino acids in the renal tubule  Nutrients carried from nephron to the body via the circulatory system  After reabsorption what remains in tubule is urine

 Some proteins are broken down in the liver  The end result creates urea  When urea combines with water and salts you end up with urine

 Kidney Stones  Rock like crystals of minerals or salts that form in urinary tract  Symptoms: sharp mid- back pain, blood in urine, painful urination  Treatment: drink lots of water, heating pads for pain  Stones will pass, if too large must be surgically removed Record: 4,504 kidney stones! 22 stones passed in 24 hours

 Cause: uric acid crystals accumulate in joints  Symptoms: severe pain, tenderness, warmth & swelling in some joints (arthritis)  Treatment: no cure but can be treated/ controlled  Anti-inflammatory drugs  Drugs to decrease uric acid levels

 Cause: an infection when bacteria cling to the opening of the urethra & multiply  Symptoms: frequent urge to urinate, painful burning feeling during urination, milky/ cloudy urine, fever (if reaches kidneys)  Treatment: antibiotics

 Cirrhosis  Cause: overloading liver with toxins such as alcohol  Liver cells die & replaced by fat & connective tissue that are not able to carry out normal liver function  Symptoms: fatigue, loss appetite, abdominal pain, weight loss  Treatment: no reversal of damage!  Treatment can stop or delay progression

 Cause: bile not excreted properly & is reabsorbed by blood  Symptoms: skin & whites of eyes turn yellow  Treatment: phototherapy: breaks down bile into components that can pass through the body

 The kidneys maintain homeostasis by:  Regulating the water content of the blood (blood volume)  Maintaining blood pH  Removing waste products from the blood

 Although you are born with two kidneys, you can live with only one kidney.  If both kidneys malfunction, a kidney dialysis machine can artificially filter blood