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EXCRETORY SYSTEM. PP 993-998. FUNCTION. Every cell in the body produces metabolic waste. The skin, lungs, and kidneys make up this system. SKIN. Excretes water, salts, small amounts of nitrogenous wastes. LUNGS. Excretes water vapor and CO 2. URINARY SYSTEM.
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EXCRETORY SYSTEM PP 993-998
FUNCTION • Every cell in the body produces metabolic waste. • The skin, lungs, and kidneys make up this system.
SKIN • Excretes water, salts, small amounts of nitrogenous wastes LUNGS • Excretes water vapor and CO2
URINARY SYSTEM • Formation and excretion of urine • Mostly water to keep wastes dissolved and easier to excrete EX. kidney stones
FILTRATION • blood forced into kidneys to clean out urea, wastes, and various substances (from aorta/artery)
REABSORPTION • some substances return to blood maintain balance (through vena cava/vein)
ELIMINATION • Urine passes through the ureters to be stored in bladder until it is secreted through the urethra
URINE • Normally made of urea, water, salt and has a very light yellow color
WHAT URINE TELLS US • Proteins may leak into the urine if the kidney is damaged • Too dark in color indicates dehydration • Brown color indicates bleeding from the kidneys • Urine will have a high glucose count if the individual is diabetic • Low or no glucose indicates hypoglycemia, which results from too much insulin
Figure 44.19-2 Osmoreceptors inhypothalamus triggerrelease of ADH. Thirst Hypothalamus Drinking reducesblood osmolarityto set point. ADH Pituitarygland Increasedpermeability Distaltubule STIMULUS:Increase in bloodosmolarity (forinstance, aftersweating profusely) H2O reab-sorption helpsprevent furtherosmolarityincrease. Collecting duct Homeostasis:Blood osmolarity(300 mOsm/L)
HOMEOSTASIS • Urine production is regulated by the antidiuretic hormone (ADH) • An increase in water in your blood triggers the release of ADH, causing your kidneys to take up more water