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Chapter 22 The Urinary System. Key Terms. angiotensin glomerulus tubular reabsorption antidiuretic hormone (ADH) hemodialysis urea calculi kidne ureter cystitis micturition urethra dialysis nephron urinalysis
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Chapter 22 The Urinary System
Key Terms angiotensin glomerulus tubular reabsorption antidiuretic hormone (ADH) hemodialysis urea calculi kidne ureter cystitis micturition urethra dialysis nephron urinalysis excretion osmolarity urinary bladder glomerular filtrate pyelonephritis urine glomerulonephritis renin
Systems Involved in Excretion • Urinary (excretory system) • Regulates volume, acid–base balance and electrolyte composition of body fluids • Main parts of the urinary system • Kidneys • Ureters • Urinary bladder • Urethra • Other systems that function in excretion: • Digestive – Respiratory – Integumentary
Systems Involved in Excretion (cont.) Figure 22-1 Urinary system. Identify the structure that carries urine to and from the bladder.
The Kidneys (cont.) Kidney Activities • Excretion • Urea • Homeostasis of body fluids • Blood pressure regulation • Hormone production • Erythropoietin (EPO)
The Kidneys (cont.) Kidney Structure • Lie against back muscles in the upper abdomen • Right kidney lower than left to accommodate liver • Enclosed in membranous renal capsule • Adipose capsule of fat • Fascia anchors the kidney to peritoneum and abdominal wall • Retroperitoneal space • Renal blood vessels • Renal artery • Renal vein
The Kidneys (cont.) Kidney Structure • Organization • Hilum • Renal cortex (outer portion) • Renal medulla (inner portion) • Renal pyramids • Renal pelvis • Calyces
The Kidneys (cont.) Kidney Structure (cont.) • Nephron and its blood supply • Nephron • Glomerular (Bowman) capsule • Renal tubule • Proximal tubule • Nephron loop • Distal tubule
The Kidneys (cont.) Kidney Structure (cont.) • Nephron and its blood supply (cont.) • Blood supply • Glomerulus • Afferent arteriole • Efferent arteriole • Peritubular capillaries
Figure 22-4 Microscopic view of the kidney. The Kidneys (cont.)
The Kidneys (cont.) Formation of Urine • Glomerular filtration • Glomerular filtrate • Tubular reabsorption • Diffusion • Osmosis • Active transport • Tubular secretion
Figure 22-5 Glomerular filtration: The first step in urineformation. The Kidneys (cont.)
The Kidneys (cont.) Formation of Urine (cont.) • Concentration of urine • The proximal tubule reabsorbs about 65% of filtered water by osmosis. • Juxtamedullary nephrons • Medullary osmotic gradient • Antidiuretic hormone (ADH)
Figure 22-6 Urine concentration. The Kidneys (cont.)
The Kidneys (cont.) Summary of Urine Formation • Glomerular filtration • Tubular reabsorption • Tubular secretion • Concentration of urine
Figure 22-7 Summary of urine formation in a nephron. The Kidneys (cont.) What vessels absorb materials that leave the nephron?
The Kidneys (cont.) The Juxtaglomerular (JG) Apparatus • Specialized region of the kidney is involved in blood pressure regulation. • Distal tubule • Afferent arteriole • Triggered by low sodium content in the glomerular filtrate. • Secretes enzyme renin • Angiotensin II
Figure 22-8 The juxtaglomerular (JG) apparatus. The Kidneys (cont.)
Elimination of Urine Elimination of Urine (cont.) The Ureters • Long, slender, muscular tubes • Extend from the kidney to urinary bladder • Entirely extraperitoneal • Move urine by gravity and peristalsis
Elimination of Urine Elimination of Urine (cont.) The Urinary Bladder • Located posterior to the pubic symphysis • Temporary reservoir for urine • Bladder wall has many layers: • Lined with mucous membrane • Rugae • Connective tissue • Involuntary muscle tissue • Parietal peritoneum • Trigone What gland does the urethra pass through in the male?
Elimination of Urine Elimination of Urine (cont.) The Urethra • Carries urine from the bladder to the outside • Differs in males and females: • Male • Approximately 20 cm in length • Serves dual purpose as part of both the reproductive and urinary systems • Female • Approximately 4cm in length • Entirely separate from the reproductive system
Elimination of Urine Elimination of Urine (cont.) Urination • Process of expelling urine from bladder (micturition) • Involuntary control • Internal urethral sphincter • Voluntary control • External urethral sphincter
Elimination of Urine Elimination of Urine (cont.) The Urine • 95% water, 5% dissolved solids and gases • pH averages 6.0 • Specific gravity measures amount of dissolved substances • Normal range 1.002 (very dilute) to 1.040 (very concentrated)
Elimination of Urine (cont.) The Urine (cont.) • Normal constituents of urine • Nitrogenous waste products • Urea • Uric acid • Creatinine • Electrolytes • Sodium and chloride ions • Sulfates • Phosphates • Pigments (e.g., urochrome, bile pigments, food pigments)
Elimination of Urine Elimination of Urine (cont.) The Urine (cont.) • Abnormal constituents of urine • Glucose • Albumin • Blood • Ketones • White blood cells • Casts
Disorders of the Urinary System (cont.) Obstructions and Structural Disorders • Hydronephrosis • Kidney stones (renal calculi) • Staghorn calculi • Renal colic • Lithotripsy (extracorporeal shock wave lithotripsy) • Structural abnormalities • Renal hypoplasia • Renal dysplasia • Ureteral stricture • Ureterocele • Hypospadias
Figure 22-10 Kidney stones. Disorders of the Urinary System (cont.) What does the word extracorporeal mean?
Figure 22-11 Hypospadias. Disorders of the Urinary System (cont.)
Disorders of the Urinary System (cont.) Inflammatory Disorders • Urinary tract infection (UTI) • Urethritis • Cystitis • Interstitial cystitis • Pyelonephritis • Glomerulonephritis
Disorders of the Urinary System (cont.) Neoplasms • Bladder tumors • Symptoms • Hematuria • Frequent urination • Causes • Toxins • Heavy cigarette smoking • Presence of urinary stones • Treatment • Tumor removal • Localized chemotherapy • Cystectomy • Ileal conduit
Figure 22-12 Cystoscopy. Disorders of the Urinary System (cont.)
Figure 22-13 Ureterocele. Disorders of the Urinary System (cont.)
Figure 22-15 Ileal conduit. Disorders of the Urinary System (cont.)
Disorders of the Urinary System (cont.) Polycystic Kidney Disease • Genetic disorder • Usually asymptomatic in children • Destruction of nephrons as disease progresses resulting in chronic renal failure • Treatment: • Renal dialysis • Kidney transplantation
Disorders of the Urinary System (cont.) Renal Failure • Renal insufficiency • Acute renal failure • Causes for acute renal failure • Medical or surgical emergencies • Toxins that damage the renal tubules • Symptoms • Sudden serious decrease in kidney function • Electrolyte imbalance • Acid–base imbalance
Disorders of the Urinary System (cont.) Renal Failure (cont.) • Chronic renal failure • Causes for chronic renal failure • Gradual loss of nephrons • Symptoms • Dehydration • Edema • Electrolyte imbalance • Hypertension • Anemia • Uremia
Disorders of the Urinary System (cont.) Renal Failure (cont.) • Renal dialysis and kidney transplantation • Dialysis • Hemodialysis • Peritoneal dialysis • Kidney transplantation • Final option for treatment of kidney failure
Disorders of the Urinary System (cont.) Urinary Incontinence • Causes • Neurologic disorder • Trauma to the spinal cord • Weakness of the pelvic muscles • Impaired bladder function • Medications • Types of urinary incontinence • Stress incontinence • Urge incontinence (overactive bladder) • Overflow incontinence • Enuresis
The Effects of Aging on the Urinary System • Loss of the kidney’s ability to concentrate urine • Decrease in number and size of nephrons • Increase in blood urea nitrogen (BUN) • Urinary infections • Prostate enlargement • Decreased bladder capacity • Incontinence
Case Study (cont.) • Urinary Obstruction • Symptoms of benign prostatic hypertrophy • Urinary urgency and frequency • Hesitation in starting stream • Decreased urine volume • Diminished force of stream • Incomplete emptying of bladder
Case Study (cont.) • Urinary Obstruction (cont.) • Diagnosis • Digital exam • Cystoscopy • Intravenous pyelogram results: • Hydroureter (from back pressure of urine) • Hydronephrosis (from back pressure of urine) • Treatment • Transurethral prostatectomy