(6) Urinary System.pdf

URINARY SYSTEM urinary system consists of: 1. Two kidneys. 2. Two ureters. transitional epithelium 3. One urinary bladder. 4. One urethra.  e e 1 Functions of The kidneys...

URINARY SYSTEM urinary system consists of: 1. Two kidneys. 2. Two ureters. transitional epithelium 3. One urinary bladder. 4. One urethra.  e e 1 Functions of The kidneys e.de 1- Excrete urine (~ 1500 – 2000 ml urine / 24 hours). It contains metabolic waste products as urea, creatinine and uric acid e 2- Regulate water and electrolyte balance and maintain acid- princessingy base balance. 3- Produce renin hormone that shares in regulation of blood sees pressure. 4- Produce erythropoietin hormone that stimulates production of f erythrocytes. ITS Hydroxylates vitamin D3 to its active form  Structure of the Kidney three 1-The stroma of the kidney cd - C.T. capsule, reticular fibers and few collagenous bundles - The kidney divide in lobes and lobules 2-The parenchyma of the kidney is formed of the urineferous tubules * The cortex (outer) has a red colour,Malpighian Renal Corpuscles. * The medulla (inner) is light grey in colour ,medullary ray consists of a collecting tubule.  en Ats ies The Urineferons Tubule Is formed Of : A) Nephrons which are the active secretory part of the urineferous tubules. B) Collecting tubules which are the execratory part of the urineferous tubules.  The Nephron The nephron is the functional and structural unit of the kidney. Each nephron is formed of: presentincortex Techie 1-The Malpighain corpuscle. 2-The proximal and distal convoluted tubules. 3-The loop of Henle. presentinmedulla  TT Iility 1-The Malpighain renal corpuscle st The Malpighian Renal corpuscles form the glomerular filtrate by the process of dialysis, each corpuscle is formed of : 0 f 1-Bowman's Capsule. 2-Glomorular Capillaries. 3-Supporting Mesangial cells. 4-Afferent and Efferent arterioles.  The Bowman's Capsule The glomerular blood capillaries are surrounded a double- Its walled capsule called Bowman's capsule which is formed tee of two continuous layers of epithelium separated by capsular space : 1- Parietal layer of Bowman's capsule which is formed of simple squamous epithelium. T tes 2-Visceral layer which is adherent to the glomerular blood capillaries. It is formed of modified simple squamous cells known as podocytes.  podocyte have small foot-like processes (pedicles) form a fenestrated tester epithelium around the fenestrated capillaries of the glomerulus.  Mesangial cells ’ They are branched cells adherent to the surface of glomerular blood capillaries. They F act as structural support to podocytes and vessels.  Juxtaglomerular Complex ’ present under the distal convoluted tubule (DCT)fits between the afferent and efferent arterioles  Differences The proximal convoluted tubules distal convoluted tubules ’ Large diameter ’ Small diameter ’ More apical microvilli ’ less apical microvilli ’ They reabsorbed: water, ’ They reabsorbed: water NaCl, Ca and phosphate; and sodium glucose, amino acids and plasma proteins ’ They excrete: sodium, ’ They excrete creatinine, potassium and iodine and penicillin ammonium. The Juxtaglomerular complex consists of : t III 1- The macula dense: detect NaCl, renin 2-The mesangial cells support distribution 3-The glomerular cells: release renin Mesangiumextraglomerularcell  The Loop of Henle It is a U-shaped tube which connects the proximal with the distal convoluted tubules of each nephron. It is formed of the following 4 parts : 1-Thick Descending part lined with simple cuboidel cells 2-Thin Descending Part lined with simple squamous cells mess s 3-Thin Ascending Part lined with simple squanous cells. 4-Thick Ascending Part lined with simple cuboidal cells. Its ’ Functions of Heul's Loop : produce hypertonic urine.  The Collecting Tubules They are lined with simple cuboidal or simple columnar cells. ’ Function : the collecting tubules conduct and as concentrate urine through reabsorption of water and secretion of potassium