Renal System Introduction PDF

‫”كلما ازددت علما ‪...‬كلما احسست وكأنني ازداد جهال ‪...‬اينشتين“‬ ‫‪Biochemistry Department‬‬ ‫‪Body Fluids‬‬ ‫‪Part 1‬‬ ‫‪Urine‬‬  Urinary system or renal system 1) kidneys are two bean shaped organs found on the left an...

‫”كلما ازددت علما ‪...‬كلما احسست وكأنني ازداد جهال ‪...‬اينشتين“‬ ‫‪Biochemistry Department‬‬ ‫‪Body Fluids‬‬ ‫‪Part 1‬‬ ‫‪Urine‬‬  Urinary system or renal system 1) kidneys are two bean shaped organs found on the left and right sides of the body responsible for clearance of substances from the blood. 2) Ureters are channels, through which urine is transported from the kidneys to the bladder. 3) Bladder collects and stores urine from the kidneys. 4) Urethra is thin tube that passes urine to the external environment. Nephron: is the structural and functional unit of the kidney. A healthy adult has 1,200,000 nephrons in each kidney. Each one is capable of forming urine by its self. It composed of : Glomerulus Tubules 1) Glomerular capillaries. 1) Proximal convoluted tubules. 2) Bowman’s capsule. 2) loop of Henle. 3) Distal convoluted tubules. 4) collecting duct. Steps of urine formation: 1)Filtration (glomerular filtration): non- selective. 2)Reabsorption (tubular reabsorption): selective. ( Tubules Blood ) 3) Secretion (tubular secretion): Highly selective. ( Blood Tubules ) *Escape Filtration *large waste product  Functions of the kidneys b) Regulatory function (Main Function) Extracellular fluid volume and blood pressure a) Excretory Ions ( Reabsorption Na+ / Excretion H+ , Cl- & function NH3 ) Remove any metabolic pH : waste product * Acidosis : Conserve HCO3- & Eliminate H+ *Alkalosis : Conserve H+ & Eliminate HCO3-  d) Metabolic Role 1) Detoxification Process by which toxic substances are c) Endocrine function converted into more soluble and less toxic Erythropoietin substances which are eliminated through Hormone urine Ex: Release Renin Inactivation of Histamine By Histaminase enzyme 2) Vitamin D3 activation by renal enzyme  Hormonal regulation: 1- Anti-diuretic hormone: H2O reabsorption. 2- Aldosterone: H2O & Na reabsorption. 3- Parathyroid hormone: Ca reabsorption Homeostasis: Renal threshold: The tendency of biological Maximum capacity of kidney system to maintain a for reabsorption condition of balance within EX: its internal environment Glucose renal threshold is *Kidney: Homeostatic 180mg/dl regulation (Balance between (If: plasma glucose level reabsorption and >180mg/dl, it will appear in excretion) urine) EX: Water and ions balance  Composition of the urine 95% water 5% solutes Organic substances Inorganic substance (a) Non protein nitrogenous compounds. Chloride (b) Proteins ( small amount Phosphate ) and other Sulphates compounds( Sugars , Calcium Hormones , Vitamins , Potassium Enzymes ) Sodium  Types of urine sample: Urine sample How Why a. Morning urine The bladder is emptied Detection of low sample before the bed time and concentration the first morning urine is substances collected. a. Random urine The sample is collected at Routine examination sample anytime a. Mid-stream urine The initial portion is Urine culture sample. allowed to escape while the mid stream portion is collected. WHY?! a. 24 hour urine Collect all the urine during Quantitative