80 likes | 201 Views
The Urinary System & Excretion. Detoxification of the Blood. The Urinary System. Remember!. The liver detoxifies the blood by removing poisonous substances and detoxifying them. the Deamination of amino acids produces ammonia, a poison, which is then converted to urea.
E N D
The Urinary System & Excretion Detoxification of the Blood
Remember! • The liver detoxifies the blood by removing poisonous substances and detoxifying them. • the Deamination of amino acids produces ammonia, a poison, which is then converted to urea. • Drug metabolism – break down of toxic substances like alcohol and medicinal products like tylenol,acetominaphen. • These products are then removed by the kidneys in the production of urine.
Functions of the Urinary System • The kidneys produce urine that is eliminated from the body. • Four functions occur during this production to help maintain homeostasis.
1. Excretion of Metabolic Wastes • The most common is nitrogenous wastes. • Amino acid breakdown ends in urea production. NH3 + CO2 • Some ammonia, NH3 is excreted as ammonium, NH4. • Creatine phosphate is a high energy reserve of phosphates for ATP production in muscles cells. Creatinine is the metabolic waste. • Nucleotide breakdown results in uric acid waste.
2. Maintenance of Water-Salt Balance • The kidneys help maintain blood pressure at its set point or homeostasis. 120/80 mmHg • Blood volume is closely linked to salt content! • Salts such as NaCl, have the ability to cause osmosis. • The more salts in the blood, the greater the blood volume, the greater the blood pressure. • Other ion maintenance in the blood such as K+, HCO3-, & Ca2+.
3. Maintenance of Acid-Base Balance • Blood pH remains between the body’s set point of 7.38 and 7.4. • If blood pH drops, becomes acidic, H+ are secreted,(excreted)and HCO3- are reabsorbed. • If blood pH rises, the opposite occurs. • H+ + NH3 NH4, if conditions are acidic. Which substance acts as a buffer? • Urine has a pH of ~ 6 due the acidic nature of foods eaten.
4. Secretion of Hormones • The kidneys aid the endocrine system with hormone production and secretion. • Renin is produced by the juxtaglomerular apparatus and released in response to low blood pressure. • This leads to the release of aldosterone from the adrenal cortex which promotes the reabsorption of Na+. • Kidneys also secrete erythropoietin in response to the low oxygen carrying capacity of the blood and rbc production is increased. • Kidneys help activate vitamin D, a hormone-like substance to promote Ca2+ absorption from the digestive tract.