620 likes | 941 Views
Chapter 13: The Urinary System. Chapter Objectives. Urinary tract and the flow of urine through the body. Kidney and the urinary bladder. Nephron, its portions and how each functions in urine formation. Relationship between the kidney and the blood circulation.
E N D
Chapter Objectives • Urinary tract and the flow of urine through the body. • Kidney and the urinary bladder. • Nephron, its portions and how each functions in urine formation. • Relationship between the kidney and the blood circulation. • Roots pertaining to the urinary system. • Major disorders of the urinary system. • Medical terms commonly used in reference to urinary system. • Abbreviations used in reference to the urinary system.
Urinary System • Function = to form and eliminate urine; regulates composition, volume, pH of body fluid • Consists of: • Two kidneys • Organs of excretion • Regulate body fluids’ composition, volume, and pH • Produces erythropoietin • Produces renin • Two ureters • Urinary bladder • Urethra
The Kidneys • Located behind peritoneum in lumbar region • Adrenal glands rest on top • Encased in fibrous connective tissue overlaid with fat • Additional layer of connective tissue supports and anchors kidney • Outer region = renal cortex • Inner region = renal medulla
The Nephrons • Microscopic working units of kidneys • Coiled tubule folded into various shapes • Bowman capsule at beginning of tubule • Cup-shaped • Part of blood-filtering device of nephron • Tubule folds into proximal convoluted tubule • Straightens to form loop of Henle • Coils into distal convoluted tubule • Straightens again to form collecting tubule
Blood Supply to the Kidney • Towards kidney, blood: • Enters through renal artery • Is brought to glomerular capsule (Bowman’s) • Then circulates through glomerulus • Away from kidney • Vessels merge into renal vein • Empty into inferior vena cava
Urine Formation • Blood pressure forces material through glomerular wall and capsule, into nephron • Glomerular filtrate consists of: • Water • Electrolytes • Soluble wastes • Nutrients • Toxins
Urine Formation (cont’d) • Urea = main waste material (byproduct of protein metabolism) • Waste material and toxins need to be eliminated • Water, electrolytes, nutrients returned to blood • Remaining fluid is urine • Adjusted by pituitary hormone ADH
Removal of Urine • Urine • Drained from renal pelvis • Carried by ureter to urinary bladder before release • Urethra • Expulses urine when bladder muscle contracts • Sphincters • Regulate urination • Upper has involuntary function • Lower functions under conscious control
Clinical Aspects of the Urinary System • Infections of urinary tract • Organisms usually enter through urethra and produce cystitis • Usually colon bacteria in feces • UTI’s more common in females
Clinical Aspects of the Urinary System (cont’d) • Infections of kidney and renal pelvis • Pyelonephritis • Symptoms include: • Dysuria • Bacteriuria • Pyuria • Urethritis • Inflammation of urethra • Associated with sexually transmitted diseases
Glomerulonephritis • Inflammation of kidney and glomeruli • Specifically occurs after immunologic reaction • Usually response to infection in another system • Symptoms: hypertension, edema, oliguria (passage of small amounts of urine)
Glomerulonephritis (cont’d) • Damage to kidney tissue • Blood and proteins escape into nephrons • Causes: hematuria, Proteinuria, Casts • May lead to: chronic renal failure, end-stage renal disease, uremia
Nephrotic Syndrome • Glomeruli become overly permeable and allow loss of proteins • Marked by proteinuria and hypoproteinemia • Affects capillary exchange • Results in edema • Liver releases lipoproteins
Acute Renal Failure • May result from damage to nephrons caused by: • Injury • Shock • Exposure to toxins • Infections • Other renal disorders • Rapid loss of kidney function • May lead to dialysis or transplantation
Dialysis • Hemodialysis = Cleansing of blood • Passed over membrane surrounded by dialysate to remove unwanted substances • Peritoneal dialysis = fluids introduced to peritoneal cavity • Periodically withdrawn with waste products • Process repeated
Urinary Stones • Called urinary lithiasis • Formed of calcium salts • May result from: dehydration, infection, abnormal urine pH, urinary stasis, metabolic imbalances • Result in extreme pain
Urinary Stones (cont’d) • Can cause: • Obstruction that can promote infection • Hydronephrosis • Stone removal • May pass on own • Surgically • Extracorporeal shock wave lithotripsy • Via endoscope
Cancer • Linked to: • Chemicals • Parasitic infections • Cigarette smoking • Key symptom is sudden, painless hematuria • Viewed or biopsy done with cystoscope
Cancer (cont’d) • Cystectomy may be required if tumor removal not effective • Other diagnosing processes: • Ultrasound • Computed tomography scans • Intravenous urography
Urinalysis • Simple, widely-used diagnosing process • Urine examined and tested for: • Color • Turbidity • Specific gravity • pH level • Chemical components • Cells, crystals, or casts
Pretest The organ that forms urine is the : (a) gallbladder (b) cystic duct (c) bladder (d) kidney
Pretest The organ that forms urine is the : (a) gallbladder (b) cystic duct (c) bladder (d) kidney
Pretest • The tube that carries urine out of the body is the: (a) pylorus (b) appendix (c) urethra (d) peristalsis
Pretest • The tube that carries urine out of the body is the: (a) pylorus (b) appendix (c) urethra (d) peristalsis
Pretest • The hormone erythropoietin stimulates production of: (a) red blood cells (b) platelets (c) leukocytes (d) saliva