BIOH 370 1st Edition Lecture 25Outline of Last Lecture Digestive System Lecture Day 3I. Large IntestineII. Phases of Digestion1. Cephalic Phase2. Gastric Phase3. Intestinal PhaseIII. Digestion1. Carbohydrate Digestion2. Protein Digestion3. Lipid DigestionIV. HormonesV. DefecationVI. Digestive System Developmental AspectsVII. ObesityVIII. Roux en Y Gastric Bypass (RYGB)IX. Metabolism and NutritionX. Metabolism During Absorptive State and Post-absorptive StateXI. ATP- Anabolic and Catabolic ReactionsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.XII. Oxidation-Reductions (redox) ReactionsXIII. Carbohydrate MetabolismXIV. ChemiosmosisXV. Glucose Anabolism and CatabolismXVI. Lipid Metabolism- Lipid Anabolism and CatabolismXVII. Protein MetabolismXVIII. VitaminsXIX. Key Molecules at Metabolic CrossroadsXX. NutritionXXI. Heat and Energy BalanceXXII. Regulation of Body Temperature XXIII. Heat StrokeXXIV. FeverXXV. Homeostatic ImbalancesOutline of Current Lecture Urinary SystemI. Urinary System FunctionsII. Renal AnatomyIII. Blood and Nerve SupplyIV. The NephronV. Renal CorpuscleVI. Glomerular FiltrationVII. Juxtaglomerular Apparatus (JGA) VIII. Renal AutoregulationIX. Renal TubuleCurrent LectureUrinary SystemI. Urinary System Functions:a. Consists of the kidneys, ureters, bladder, and urethrab. Maintains homeostasis by managing the volume and composition of fluid reservoirs, primarily bloodc. Regulation of blood ionic composition- Na+, K+, Cl–d. Regulation of blood pH- H+, HCO3–e. Regulation of blood volume- H20f. Regulation of blood pressureg. Maintenance of blood osmolarityh. Production of hormones- Calcitrol and Erythropoietini. Regulation of blood glucose levelj. Excretion of metabolic wastes and foreign substances (drugs or toxins)II. Renal Anatomy: kidneys are retroperitoneal, partly protected by the lower ribsIII. Blood and Nerve Supply:- Renal arteries deliver ~ 1/4 (1200 ml) of cardiac output to the kidneys each minute- Arterial flow into and venous flow out of the kidneys follow similar paths- Nerve supply is via sympathetic fibers from the renal plexusIV. The Nephron:- Structural and functional units that form urine- ~1 million per kidney- Two main parts1. Glomerulus : a tuft of capillaries 2. Renal tubule: begins as cup-shaped glomerular (Bowman’s) capsule surrounding the glomerulusThe kidneys filter the body’s entire plasma volume 60 times each day• Glomerular filtration, • tubular reabsorption • tubular secretion• Filtrate• Blood plasma minus proteins• Urine• <1% of total filtrate• Contains metabolic wastes and unneeded substancesV. Renal Corpuscle:- The glomerular endothelial cells have large pores (fenestrations) and are leaky.- Basal lamina lies between endothelium and podocytes.- Podocytes form pedicels, between which are filtration slits.VI. Glomerular Filtration•• Driven by blood pressure• Opposed by capsular hydrostatic pressure and blood colloid osmotic pressure• Water and small molecules move out of the glomerulus.• In one day, 150–180 liters of water pass out into the glomerular capsule.• Glomerular filtration rate – amount of filtrate formed by both kidneys each minute• Homeostasis requires kidneys to maintain a relatively constant GFR• Too high – substances pass too quickly and are not reabsorbed• Too low – nearly all reabsorbed and some waste products not adequately excretedVII. Juxtaglomerular Apparatus (JGA): senses NaCl and Blood Pressure- Granular cells (juxtaglomerular, or JG cells)1. Enlarged, smooth muscle cells of arteriole2. Secretory granules contain renin3. Act as mechanoreceptors that sense blood pressure- Macula densa1. Tall, closely packed cells of the ascending limb2. Act as chemoreceptors that sense NaCl content of filtrate- Extraglomerularmesangial cells 1. Interconnected with gap junctions2. May pass signals between macula densa and granular cells- Glomerular filtration rate – amount of filtrate formed by both kidneys each minute1. Homeostasis requires kidneys to maintain a relatively constant GFRa. Too high – substances pass too quickly and are not reabsorbedb. Too low – nearly all reabsorbed and some waste products not adequately excreted- GFR averages 125mL/min in males and 105mL/min in females- Controlled by:Renal AutoregulationNeural RegulationHormonal RegulationVIII. Renal Autoregulation- Myogenic Mechanism- Smooth muscle cells in afferent arterioles contract in response to elevated blood pressure- Tubuloglomerular Feedback1. High GFR diminishes reabsorption2. Macula Densa inhibits release of nitric oxide3. Afferent arterioles constrict- Substances that are filtered reabsorbed and excreted in urine dailyIX. Renal Tubule:- The filtrate passes from the glomerular capsule to the renal tubule1. Proximal Convoluted Tubule2. Nephron Loop Descending Loop Ascending Loop3. Distal Convoluted