Lecture AP Biology Chapter 44 Controlling the internal environment

After studying this chapter you will be able to understand: Three categories of nitrogenous waste, which animal groups produce each, and why; the components of a nephron, and what occurs in each regionl; how hormones affect water balance by acting on the nephron.

Ch 44 Warm-Up Draw and label the parts of a nephron What are the 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? Controlling the Internal Environment Chapter 44 What 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/loss  Excretion: removal of nitrogenous wastes from body Types of Nitrogenous Wastes: Wastes Ammonia – water soluble, very toxic; aquatic animals Urea – produced by liver; less toxic, conserves water; most vertebrates Uric acid – excreted as paste or crystals; birds & reptiles Types of Nitrogenous Wastes Various forms of excretory systems Protonephridia - Platyhelminthes (Planaria) Metanephridia - Annelida Malpighian tubules – Insects, arthropods Kidneys - Vertebrates How to make  Water and solutes enter filtrate; blood urine: cells and proteins remain in body fluid  Reclaim glucose, vitamins, hormones  Add toxins and excess ions  Filtrate leaves body as urine Mammalian Excretory System Nephrons: functional units of the kidney • Glomerulus: filtrate forced into Bowman’s capsule • Blood cells and proteins DO NOT enter filtrate Processing of blood filtrate: Proximal tubule: secretion & reabsorption change volume and composition of filtrate  Bicarbonate, NaCl, water is absorbed Descending loop of Henle: reabsorb water Ascending loop of Henle: reabsorb salt Distal tubule: K+ and NaCl levels regulated Collecting duct: filtrate becomes more concentrated; minimize water loss From blood filtrate to urine SECRETION FILTRATION REABSORPTION EXCRETION Hormones  Antidiuretic Hormone (ADH):  urine concentration, reduce H2O loss  Also called vasopressin  Renin/angiotensin II: raise blood pressure  Aldosterone:  Na+ reabsorption,  H2O retention, blood volume, pressure Blood Pressure Regulation  Urine exits kidney through Ureters  Bladder: Bladder stores urine  Urethra: Urethra urine exits body Believe it or not…  Your kidneys are only in long and weigh about        oz (weight of ½ unfinished can of pop) Usually we urinate 1.5-2.5 liters/day 44 gallons of blood is filtered by kidneys everyday-2 bathtubs full Fresh urine is cleaner than spit, cleaner than your hands after they have been washed and cleaner than the sandwich you will eat for lunch Gandhi drank urine every day (Tantric Yoga practice) Gladiators brushed their teeth with it Colonial housewives cleaned their home with it 1st football=pig bladder .. .Controlling the Internal Environment Chapter 44 What you must know:  Three categories of nitrogenous waste, which animal groups produce each, and why  The components of a... liters/day 44 gallons of blood is filtered by kidneys everyday-2 bathtubs full Fresh urine is cleaner than spit, cleaner than your hands after they have been washed and cleaner than the sandwich... body as urine Mammalian Excretory System Nephrons: functional units of the kidney • Glomerulus: filtrate forced into Bowman’s capsule • Blood cells and proteins DO NOT enter filtrate Processing of