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Excretory System. Functions. removes dangerous , unnecessary, or excess materials from the body allows the body to maintain homeostasis (stable internal environment). A. Important Organs. Skin: excretes sweat (excess water, salts, and urea)
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Functions • removes dangerous, unnecessary, or excess materials from the body • allows the body to maintain homeostasis (stable internal environment)
A. Important Organs • Skin: excretes sweat (excess water, salts, and urea) • Urea: toxic compound (amino acids energy) • Lungs: excretes CO2 (cellular respiration)
Liver: breaks down toxins (ammonia urea) • Maintains blood glucose levels • Large intestine: reabsorbs water and excretes waste
Kidneys: remove waste from blood, maintain blood pH, regulate H2O content of blood • Ureter: tube that carries urine from kidney to bladder • Bladder: where urine is stored before being excreted • Urethra: tube through which urine is excreted
B. Nephron • Filtration: renal artery brings waste-filled blood to the kidneys • In the glomerulus (capillaries), water and dissolved particles (filtrate) are pulled out of the blood into the Bowman’s capsule • filtrate: water, salts, urea, glucose, amino acids, vitamins
Reabsorption: in proximal tubule, water and nutrients are reabsorbed by the capillaries • Loop of Henle: urine is concentrated and water is conserved • 99% of water is reabsorbed
Secretion: in the distal tubule, wastes that were not initially filtered out are removed from the blood • Collecting duct: filtrate, now called urine, is emptied here • Renal vein returns purified blood to body