Regulation of Body Fluids and Excretion: Urinary System, Liver and Metabolic Waste Management

Apuntes

YEAR 11 HUMAN BIOLOGY Regulation of the Composition of Body Fluids Learning Outcomes ⚫the excretory system regulates the chemical composition of body fluids by removing metabolic wastes and retaining the proper amounts of water, salts, and nutrients; components of this system include the kidneys, liver, lungs, and skin functioning at the organ level ⚫deamination of amino acids in the liver produces urea, which then is transported to the kidneys for removal ⚫the nephrons in the kidney facilitate three basic processes: filtration, reabsorption and secretion during urine formation to maintain the composition of body fluids (hormone control is not required) Homeostatic Functions of the Urinary System 5 Homeostatic Functions of Urinary System 1. Regulate blood volume and blood pressure: ⯍ by adjusting volume of water lost in urine 2. Regulate plasma ion concentrations: ⯍ sodium, potassium, and chloride ions (by controlling quantities lost in urine) ⯍ calcium ion levels 3. Help stabilize blood pH: ⯍ by controlling loss of hydrogen ions and bicarbonate ions in urine 4. Conserve valuable nutrients: ⯍ by preventing excretion while excreting organic waste products 5. Assist liver to detoxify...