CBIO 2210 week 10 notes
CBIO 2210 week 10 notes CBIO2210
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This 3 page Class Notes was uploaded by Elise Weidner on Wednesday March 30, 2016. The Class Notes belongs to CBIO2210 at University of Georgia taught by Rob Nichols in Spring 2016. Since its upload, it has received 11 views. For similar materials see Anatomy and Physiology II in Anatomy at University of Georgia.
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Date Created: 03/30/16
CBIO 2210 Notes 3/22/16 Urinary System: Chapter 25 Renal Functions Kidneys make urine from blood o The kidneys filter blood but there is an intermediate fluid called filtrate before the end product of urine Removal of… o toxins, o metabolic wastes (4 major types), o excess ions (ex: calcium, hydrogen ions (pH) ) from blood Regulation of… o blood volume, o chemical composition, o pH Gluconeogenesis during prolonged fasting o Making glucose out of non-carbohydrates o Keeps blood sugar from falling Endocrine functions o Erythropoietin (hormone that kidneys produce during low O2 levels): regulation of RBC production Regulation of blood pressure o Renin (enzyme released by kidneys): regulation of blood pressure and kidney function Synthesis of vitamin D precursor o Vitamin D needed to absorb Calcium 4 Nitrogenous wastes Each have nitrogen molecule Ammonia (removed ammonia from amino acids is called deamination) o Very dangerous and toxic to red blood cells in moderate amounts o Liver adds CO2 to ammonia to make it Urea Urea o Ammonia removed from protein with CO2 added Uric acid o Made from excessive adenine and guanine from DNA or RNA Creatinine o Creatine in muscles can be used to convert ADP to ATP and becomes creatinine o Mostly comes from cardiac and skeletal muscle o More accurate indicator if kidney malfunction than other wastes (if high in blood and low in urine) Renal Microanatomy Nephrons: the structural and functional units that form urine o Tubules that receive blood and change it to urine Approx. 1 million / kidney 2 main parts: o Renal corpuscle: Glomerulus (tuft/cluster of capillaries) + Bowman’s capsule (surrounds glomerulus) o Renal tubule: begins as a cup-shaped glomerular (Bowman’s) capsule surrounding the glomerulus Fenestrated glomerular endothelium o allows filtrate to pass from plasma into the glomerular capsule Nephron Types Cortical (85%) o More in cortex of kidney Juxtamedullary (15%) o Nephron loop that dips deep in medulla o Do 80% of water reabsorption Juxtaglomerular Apparatus (JGA) Regulates filtrate formation and systemic blood pressure Involves modified portions of the: o distal convoluted tubule o afferent arteriole of glomerulus 2 important populations of cells: o granular cells (or JG cells) enlarged smooth muscle cells around afferent arteriole Can constrict secretory granules containing renin mechanoreceptors that detect changes in BP o macula densa DCT cells that are chemoreceptors responding to changes in NaCl concentrations of filtrate Filtration Membrane Porous membrane between the blood and the capsular space Consists of: o fenestrated endothelium of the glomerular capillaries o visceral membrane of the glomerular capsule: podocytes with foot processes and filtration slits podocytes control how much blood flows through tube by covering or uncovering holes (like recorder) o Gel-like basement membrane: fused basal lamellae of the two other layers Allows passage of water and solutes smaller than most plasma proteins o fenestrations prevent filtration of blood cells o negatively charged basement membrane repels large anions such as plasma proteins o Slit diaphragms also repel macromolecules Kidney Physiology: Mechanisms of Urine Formation The kidneys filter the body’s entire plasma volume (3 liters) > 60 times / day 99% gets reabsorbed back into body Filtrate o blood plasma minus proteins Urine o contains metabolic wastes and un-needed substances o <1% of total filtrate (what happens to the other 99%?)