Y khoa - Dược - Chapter 31: The urinary system

31The UrinarySystemLearning Outcomes (cont.)31.1 Describe the structure, location, and functions of the kidney. 31.2 Explain how nephrons filter blood and form urine. Learning Outcomes (cont.)31.3 Compare the locations, structures, and functions of the ureters, bladder, and urethra.31.4 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the urinary system. IntroductionSystem functions to remove waste products from the bloodNephrons filter the blood and form the urineUrinary System OrgansKidneysUretersBladderUrethraThe KidneysMaintain homeostasisRemove metabolic waste productsSecrete hormonesErythropoietin Renin Retroperitoneal at level of lumbar vertebraeKidneysBackThe Kidneys (cont.)Renal sinus Concave depression on the kidney's surfaceHilum Renal pelvis Expansion of the ureter Divides into calycesKidneyRenal cortex – outermost layerRenal medullaMiddle portion Divides into renal pyramidsRenal column – between pyramidsThe Kidneys (cont.)KidneyBackNephronsRenal corpuscle Glomerulus ~ capillariesBowman’s capsuleNephron NephronsRenal tubules – extend from Bowman’s capsuleProximal convoluted tubuleLoop of HenleDistal convoluted tubuleNephron Nephrons (cont.)Afferent arteriolesRenal arteryEfferent arteriolesPeritubular CapillariesRenal veinNephron Glomerulus BackApply Your KnowledgeWhat is the function of the kidney?ANSWER: Maintain hemostasis by removing metabolic waste products from the blood, secreting erythropoietin to help regulate RBC production, and secreting renin to help regulate the BP.Correct!Urine FormationGlomerular FiltrationOccurs in renal corpusclesFluid part of the blood Into Bowman’s capsuleBecomes glomerular filtrateGlomerulus Urine Formation (cont.)Glomerular filtration Filtration pressure – that needed to force filtrate from the glomerulus into Bowman’s capsuleRate of filtration Sympathetic nervous system controlConstriction of afferent arteriolesGlomerulus PreviousTubular ReabsorptionGlomerular filtrate  proximal convoluted tubuleReabsorption of needed substancesWater reabsorption  hormonal regulation Antidiuretic hormone (ADH)Aldosterone water reabsorption,  urine productionTubular ReabsorptionTubular Secretion Substances move from blood in the peritubular capillaries into the renal tubulesSecreted substancesDrugsHydrogen ionsWaste productsTubular SecretionTubular ReabsorptionTubular SecretionPreviousUrine CompositionMostly waterUrea and uric acidTrace amounts of amino acids and various ionsSecretion of waste products helps to maintain the acid-base balanceApply Your KnowledgeMatch the following:___ Second process in urine formation___ Substances move from blood  into renal tubules reabsorption___ Depends on filtration pressure ___ Third process of urine formation___ First process of urine formation___ Filtrate flows into the proximal convoluted tubuleCCBAABANSWER:Glomerular filtrationTubular ReabsorptionTubular SecretionThe Ureters, Urinary Bladder, and UrethraUretersLong muscular tubes Carry urine to the bladder using peristalsisUrinary BladderTrigone – triangle on internal floor of bladder Detrusor muscle – smooth muscle of bladder wall MicturitionProcess of urinationTriggered by stretching of the bladderBladderPreviousMicturitionImpulses to contract urethra  inhibit micturition impulse until ready to urinateUrinary Bladder (cont.)BladderdistendsStretch receptorsSpinal cordParasympathetic nerves stimulate detrusor muscleBrain stemand cerebralcortexUrethraMoves urine from the bladder to the outside worldShorter in females – patient educationUrinate when urge occursDrink adequate clear fluidsWipe front to backUrinate after intercourseUrethraTrue or False:___ Ureters move urine by peristalsis.___ The detrusor is formed by the openings of the ureters  and urethra.___ The process of micturition is triggered when the bladder  contains about 150 ml urine.___ The urethra move urine from the kidney to the bladder.___ The urethra is longer in females.___ Contraction of the detrusor muscle pushes urine from  the bladder.Apply Your KnowledgeFFTFTmalesuretersTANSWER:Impressive!trigoneDiseases and Disorders of the Urinary SystemDisease/DisorderDescriptionAcute kidney (renal) failureSudden loss of kidney function; may be reversible with treatmentChronic kidney (renal) failureKidneys slowly lose ability to function; not reversibleCystitisUrinary bladder infection; more common in femalesDiseases and Disorders of the Urinary SystemDisease/DisorderDescriptionGlomerulonephritisInflammation of the glomeruli of the kidney; one cause of chronic renal failureIncontinenceInability to control urinationPolycystic kidney diseaseEnlargement of kidneys because of the presence of many cysts within them; slow, progressive diseaseDiseases and Disorders of the Urinary SystemDisease/DisorderDescriptionPyelonephritisComplicated urinary tract infection; begins with a bladder infection and spreads to both kidneys; can be acute or chronicRenal calculiKidney stones; can become lodged in ducts within kidneys or uretersApply Your KnowledgeMatching:___ Complicated urinary tract infection A. Pyelonephritis___ Inability to control urination B. Glomerulonephritis___ Kidney stones C. Incontinence___ Slow loss of kidney function D. Chronic renal failure___ Bladder infection E. Renal calculi___ Inflammation of the glomeruli F. Cystitis___ Kidney enlargement due to cysts G. Acute renal failure___ Sudden loss of kidney function H. Polycystic kidney diseaseHGFEDCBAANSWER:GOOD JOB!In Summary31.1 The retroperitoneal kidneys are composed of the outer renal cortex and inner renal medulla. Their function is to remove metabolic wastes from the body. In Summary31.2 A nephron is a single kidney cell. It is composed of a renal corpuscle composed of the glomerulus and the Bowman’s capsule and the three sections of the renal tubule: the proximal convoluted tubule, the loop of Henle, and the distal convoluted tubule. The nephrons filter blood and form urine through three processes: glomerular filtration, tubular reabsorption, and tubular secretion. In Summary (cont.)31.3 The ureters are long tubes extending from each renal pelvis that bring urine to the bladder for storage. The urethra is the muscular tube extending from the bladder that allows urine to be expelled from the body. In Summary (cont.)31.4 There are many common diseases and disorders of the urinary system with varied signs, symptoms, and treatments. Some of these include acute kidney (renal) failure, chronic kidney (renal) failure, cystitis, glomerulonephritis, incontinence, polycystic kidney disease, pyelonephritis, and renal calculi.End of Chapter 31This too shall pass—just like a kidney stone.~H. Madson