<p> Mercer County Community College Science/Allied Health</p><p>Bio 104 Lecture Outline Urinary System Course Coordinator: Chapters: 24, 25</p><p>L. Falkow 3/05</p><p>I. Introduction</p><p>A. Components 1. Kidneys nephron 2. Ureters 3. Urinary bladder 4. Urethra</p><p>B. Functions 1. Regulate blood volume and BP</p><p>2. Regulate concentration of ions </p><p>3. Regulate blood pH</p><p>4. Eliminate waste products</p><p>5. Help liver in detoxification of poisons</p><p>II. The Kidneys A. Gross Anatomy 1. Location</p><p>2. Size and shape</p><p>3. Surrounding structures: a. liver, colon, duodenum</p><p> stomach, pancreas, jejunum, colon</p><p> b. fat and CT innermost: renal capsule middle: adipose capsule outermost: renal fascia</p><p>Clinical condition: floating kidney</p><p> c. adrenal glands</p><p> d. ureters</p><p>B. Sectional Anatomy 1. hilus (hilum) 2. cortex 3. medulla 4. renal pyramids 5. renal papilla 6. renal columns 7. renal pelvis 8. minor and major calyx (calyces)</p><p>C. The Nephron = renal corpuscle + renal tubule</p><p>1. Renal corpuscle a. Bowman's capsule parietal epithelium: </p><p> capsular space:</p><p> visceral epithelium: b. Glomerular capillaries</p><p> filtration membrane:</p><p>Glomerulonephritis -</p><p>2. Tubules</p><p> a. proximal convoluted tubules (pct)</p><p> function</p><p> b. loop of Henle </p><p> descending limb</p><p> ascending limb</p><p> c. distal convoluted tubules (dct)</p><p> function</p><p> d. Juxtaglomerular apparatus (JGA) = macula densa + juxtaglomerular cells EPO (hormone)</p><p> renin (enzyme) When BP is too low, JG cells secrete renin. Renin-angiotensin system is activated and angiotensin is formed which ______BP.</p><p> e. Collecting System</p><p> collecting ducts</p><p> papillary ducts</p><p>Urine collecting duct papillary duct --> minor calyx ---> major calyx ---> renal pelvis ---> ureter ---> urinary bladder ---> urethra ---> OUTSIDE the body</p><p>3. Nephrons (2 types): cortical</p><p> juxtamedullary</p><p>D. Blood Supply to the Kidneys</p><p>1. Route of blood: Renal artery -----> ______----> Interlobar arteries</p><p>---> Arcuate arteries ----> ______------> Afferent arteriole</p><p>---> Glomerulus ----> ______----> Peritubular capillaries, Vasa recta</p><p>------> Interlobular veins ------> ______------> </p><p>Interlobar veins ------> Segmental veins ---> ______</p><p>2. Distinctive features: a. 2 capillary beds</p><p> b. efferent arteriole</p><p>More resistance to flow out of the glomerulus than going into the glomerulus.</p><p>III. Renal Physiology</p><p>A. Basic Principles of Urine Formation waste products: urea</p><p> creatinine</p><p> uric acid</p><p> processes: filtration</p><p> reabsorption</p><p> secretion</p><p>B. Filtration</p><p>1. Pressures</p><p> glomerular hydrostatic press. (GHP)</p><p> capsular hydrostatic press. (CsHP)</p><p> blood colloid osmotic pressure (BCOP)</p><p>Filtration pressure (FP) = (GHP - CsHP) - BCOP</p><p>2. Glomerular Filtration Rate (GFR) = 125 ml/min ---> 180 liters/day</p><p>3. Glomerular filtrate Small molecules and ions can pass through filtration slits:</p><p>Ions Nutrients Wastes H2O Na+ glucose urea K+ a.a. creatinine Cl- ammonia</p><p>HCO3- uric acid</p><p>C. Reabsorption 1. ~ 99% of filtrate is reabsorbed</p><p>2. Only certain substances are reabsorbed:</p><p>H2O, ions, glucose, a.a.</p><p>3. Reabsorption occurs by: facilitated diffusion active transport diffusion osmosis countercurrent</p><p>Hydrostatic pressure in peritubular capillaries -</p><p>Osmotic pressure in peritubular capillaries -</p><p>===> osmotic pull is stronger and diffusion gradient is set up that is greater in</p><p> the peritubular capillaries than the hydrostatic force OUT of these capillaries.</p><p>===> much of H20, ions, a.a. are reabsorbed (returned) to the blood.</p><p>D. Countercurrent multiplication - based on arrangement of:</p><p>1. increasing concentration of salt, progressing from cortex ---> tip of medullary pyramid</p><p>2. max. conc. that can develop: ~ 1200 mOsm/l 3. fluid delivered to dct is hypotonic (~1/3 of solute conc. as the pct)</p><p>Functions: ** 1) efficient way to reabsorb water and solutes before filtrate (tubular fluid) reaches dct and collecting system</p><p>** 2) sets up a concentration gradient that allows passive reabsorption of water from tubular fluid in collecting system E. Secretion -</p><p>Ions Wastes Others K+, H+ ammonia neurotransmitters creatinine histamine some drugs</p><p>1. rids body of certain materials</p><p>2. controls blood pH by secretion of: H+ and NH4+ ---> urine pct loop of Henle dct collecting system</p><p>F. Control of Urine volume and Osmolarity</p><p> obligatory water reabsorption</p><p> facultative water reabsorption</p><p>ADH: If solute conc. is too high in blood (ex. salt): hypothalamus ---> post. pituitary ---> plasma ADH </p><p>---> increased H2O reabsorption in dct and collecting system</p><p> diabetes insipidus: deficiency of ADH</p><p>Aldosterone:</p><p>G. Vasa Recta</p><p>H. Summary of Renal Function</p><p>I. Composition of Urine</p><p> pH Specific Gravity</p><p>H2O Volume Color Odor Bacteria</p><p>IV. The Ureters, Urinary bladder, and Urethra</p><p>A. Ureters 1. Characteristics 2. Histology</p><p>3 tissue layers:</p><p> calculi =</p><p>B. Urinary bladder</p><p>1. Characteristics</p><p> rugae</p><p> trigone</p><p>2. Histology</p><p> detrusor muscle</p><p>C. Urethra</p><p> external urethral sphincter</p><p>Female Male size: 3-5 cm 18-20 cm walls: ext. sphincter: urinary & reproductive passageways: separate together</p><p> parts: single 3 parts: structure prostatic membranous penile </p><p>D. Micturition</p><p>1. micturition reflex</p><p> combination of involuntary and voluntary responses</p><p>V. Clinical Situations</p><p>Glomerulonephritis</p><p>Hemodialysis</p><p>Calculi</p>