Urinary System 2009 revised - 1 Urinary System 2010 In...

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1 Urinary System 2010 In addition to web sites already suggested, you may want to visit: http://education.vetmed.vt.edu/Curriculum/VM8054/Labs/Lab23/lab23.htm# . I personally think the SIUSOM web site is the best for the renal system. Do not forget that the kidneys have been called the “the brain” below the diaphragm, but we know much more about the kidneys than we do about the brain, but it is very complex and involves much physiology. I have a textbook on renal pathology from 1966 which has 45 pages on renal anatomy and histology. If this book was written today, instead of 800+ pages, it would be 1600 pages and the anatomy and histology section would be expanded to 90 or more pages. In these notes, I have tried to give you some basic information about the physiology of the kidney as well as the histology. "The composition of the body is determined not by what the mouth takes in but by what the kidney keeps." (Homer Smith, renal physiologist) The urinary system consists of paired kidneys and ureters, the urinary bladder, and urethra. A. Functions: 1. Regulation of volume and composition of body fluid which includes salt and water balance, preservation of nutrients, excretion of wastes (urea), acid-base balance. 2. Filtration of blood (at a rate of 120 ml per minute), reabsorption of 99% of this filtrate which includes all glucose, amino acids, most of the water and salts, and secretion of K + , H + , NH 4 + , etc. This all results in approximately 1500 ml of urine per day after the kidney has filtered nearly 200,000 ml of blood per day; 3. Endocrine function includes secretion of rennin, erythropoietin, and Vitamin D (calcitriol, the active form of Vit D). B. Structure: the functional and structural unit of the kidney is the NEPHRON consisting of renal corpuscle (Bowman's capsule and the glomerulus), proximal convoluted tubule, loop of Henle, and distal convoluted tubule which lead to collecting tubules which join to form collecting ducts. Each nephron consists of vascular elements and tubular elements. Each kidney has over a million nephrons and the simple tubular epithelium measures approximately 25 miles. The kidneys are covered by a capsule, but within the parenchyma of the kidney, there is very little CT unlike most other glands. The kidney is divided into an outer cortex and a thicker inner medulla . All the renal glomeruli reside in the cortex but the bulk of the substance in the cortex are the proximal and distal convoluted tubules. The medulla has no glomeruli and consists mostly of renal tubules, the pars recta of the proximal tubule, loop of Henle, the pars recta of the distal tubule, and collecting ducts and blood vessels, capillaries, associated with these tubules. These tubules lie very close
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2 together forming the medullary pyramids. Separating the medullary pyramids are the renal columns of Bertin which contain some CT carrying the interlobar arteries C. The renal corpuscle is composed of two structures: Bowman’s capsule and the
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This note was uploaded on 11/08/2011 for the course SCIENCE 3254 taught by Professor Dr.shoupe during the Spring '11 term at Fort Valley State University .

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Urinary System 2009 revised - 1 Urinary System 2010 In...

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