Sinh học - Chương 44: Warm up

Ch. 44 Warm-UpDraw and label the parts of a nephron.What are the 4 main functions of a nephron?Where does each function in #2 above occur in a nephron?In the glomerulus, which substances are filtered? Which substances remain in the blood?Chapter 44Controlling the Internal EnvironmentWhat you must know:Three categories of nitrogenous waste, which animal groups produce each, and why.The components of a nephron, and what occurs in each region.How hormones affect water balance by acting on the nephron.Osmoregulation: control solute concentrations and balance water gain/lossExcretion: removal of nitrogenous wastes from bodyTypes of Nitrogenous Wastes:Ammonia – water soluble, very toxic; aquatic animalsUrea – produced by liver; less toxic, conserves water; most vertebratesUric acid – excreted as paste or crystals; birds & reptilesTypes of Nitrogenous WastesVarious forms of excretory systemsProtonephridia - Platyhelminthes (Planaria)Malpighian tubules – Insects, arthropodsMetanephridia - AnnelidaKidneys - VertebratesLeast  Most Complex:Protonephridium: closed tubes lacking an internal opening capped by a cellular unit called flame bulb. Urine passes out of small pores.Metanephridia: internal openings collect body fluids into a long tube surrounded by capillaries. Urine exits out pores.Malpighian tubes: remove N waste from hemolymph, located near digestive tract. Secretes dry waste with feces.Kidneys: compact organs containing tubules surrounded by capillaries. Functions in water and blood filtration, excretion of N waste and saltWater and solutes enter filtrate; blood cells and proteins remain in body fluid.Reclaim glucose, vitamins, hormonesAdd toxins and excess ionsFiltrate leaves body as urineHow to make urine:Mammalian Excretory SystemNephrons: functional units of the kidneyGlomerulus: filtrate forced into Bowman’s capsule.Blood cells and proteins DO NOT enter filtrateProcessing of blood filtrate:Proximal tubule: secretion & reabsorption change volume and composition of filtrateBicarbonate, NaCl, water is absorbedDescending loop of Henle: reabsorb waterAscending loop of Henle: reabsorb saltDistal tubule: K+ and NaCl levels regulatedCollecting duct: filtrate becomes more concentrated; minimize water lossFrom blood filtrate to urineFILTRATIONREABSORPTIONSECRETIONEXCRETIONAntidiuretic Hormone (ADH):  urine concentration, reduce H2O lossAlso called vasopressinRenin/angiotensin II: raise blood pressureAldosterone:  Na+ reabsorption,  H2O retention, blood volume, pressureHormonesBlood Pressure RegulationUrine exits kidney through UretersBladder: stores urineUrethra: urine exits bodyBelieve it or notYour kidneys are only 4 in long and weigh about 5 oz (weight of ½ unfinished can of pop)Usually we urinate 1.5-2.5 liters/day44 gallons of blood is filtered by kidneys everyday-2 bathtubs fullFresh urine is cleaner than spit, cleaner than your hands after they have been washed and cleaner than the sandwich you will eat for lunchGandhi drank urine every day (Tantric Yoga practice)Gladiators brushed their teeth with itColonial housewives cleaned their home with it1st football=pig bladder