Unit 16 Urinary System
Unit 16: The Urinary System
Page 1
Introduction to the Urinary System
Prepared by Wendi Roscoe, edited by Claudia Schubert, Ph.D., OCT and Laren Bron MSc WWHP
Copyright © 2016 by Nelson Education Ltd.
Page 2: Lecture Outcomes
16.1 Explain the functions of the urinary system.
16.2 Identify the excretory organs of the body and their methods of waste excretion.
16.3 Describe the structure and function of urinary organs.
16.4 Explain the nephron's physiology and urine production.
16.5 Describe regulation of urine formation.
16.6 Identify normal and abnormal urine constituents.
16.7 Discuss urinary system disorders and their causes.
Page 3: Excretory Organs
Skin (Integumentary System): Waste excretion via sweat.
Lungs (Respiratory System): Carbon dioxide excretion through breathing.
Kidneys (Urinary System): Main organ for waste elimination.
Page 4: Functions of the Urinary System
Regulation of Blood Composition
Maintains blood water and ion levels.
Waste Excretion: Eliminates metabolic waste products.
Blood Pressure Regulation: Kidneys are key regulators.
pH Regulation: Excretes excess hydrogen ions.
Hormones Released:
Calcitriol: Active vitamin D form.
Erythropoietin: Stimulates red blood cell production.
Page 5: Organs of the Urinary System
Kidneys: Main organs for filtration.
Ureters: Transport urine from kidneys to bladder.
Urinary Bladder: Stores urine.
Urethra: Discharges urine from the body.
Page 6: Structure and Function of Urinary Organs
Kidneys: Regulate volume, composition, blood pressure, and pH; produce hormones and excrete wastes.
Ureters: Carry urine to bladder.
Urinary Bladder: Store and expel urine.
Urethra: Sphincters control urine discharge.
Page 7: Anatomy of the Kidneys
Size and Location: Each about 3 inches long, positioned retroperitoneally between T12 and L3.
Blood Supply: Receives over 20% of heart's output through renal arteries.
Asymmetry: Right kidney is positioned lower than the left.
Page 8: Kidney Location and Support
Adrenal Glands: Located on top of each kidney.
Position: Diagram showing kidney placement relative to vertebrae and ribs.
Page 9: Kidney Support Structures
Surrounding Structures: Includes paranephric fat, renal fascia, and fibrous capsule.
Page 10: Kidney Anatomy
Major Components:
Renal Capsule, Medulla, Cortex, and Nephron.
Renal Vasculature:
Renal artery, vein, pelvis, and calyx.
Page 11: The Nephron
Structure: Functional unit of the kidney; over 1 million per kidney.
Parts: Composed of renal corpuscle and renal tubule.
Page 12: Nephron Capillary Network
Vascular Components: Glomerular capsule and different arterioles interact within the nephron.
Page 13: Renal Tubule Structure
Structure consists of:
Proximal convoluted tubule
Nephron loop (descending and ascending limbs)
Distal convoluted tubule
Collecting duct
Page 14: Simplified Nephron Structure
Visuals illustrating parts of the nephron including various tubule segments.
Page 15: Nephron Functions Overview
Key Functions:
Filtration
Reabsorption
Secretion
Hydraulic Coordination: Arterioles help facilitate blood flow and solute management.
Page 16: Nephron Function Details
Filtration: Fluid moves from glomerular capillaries into Bowman’s capsule.
Reabsorption: Nutrients and ions are reclaimed into the bloodstream.
Secretion: Wastes are secreted into nephron from capillaries.
Excretion: Final urine flows from nephron to bladder.
Page 17: Filtration Process in the Nephron
Capillary Types: Glomerular capillaries are unique for their filtration capabilities.
High Blood Pressure: Ensures efficient solute movement into Bowman’s capsule.
Page 18: Filtration Pressures
Key pressures affecting filtration:
Hydrostatic pressure in glomerular and Bowman’s capsule.
Page 19: Efficient Filtration
Passive Filtration: Hydrostatic pressure moves fluids across membranes.
High Output: Kidneys process significant volumes of fluid daily (180 L).
Page 20: Importance of Plasma Proteins
Proteinuria: Presence of blood cells/proteins in urine signals filtration membrane damage, indicative of health issues.
Page 21: Glomerular Filtration Rate (GFR)
Healthy kidneys filter approx. 125 mL/min.
Used as a kidney health indicator.
Page 22: Stages of Chronic Kidney Disease (CKD)
Progressive Stages:
Stage 1: Normal function (90-100% GFR)
Stage 2: Mild loss (89-60% GFR)
Stage 3a & 3b: Moderate loss (59-30% GFR)
Stage 4: Severe loss (29-15% GFR)
Stage 5: Kidney failure (less than 15% GFR)
Page 23: Tubular Reabsorption in the Nephron
Movement of nutrients and water back to blood.
Majority occurs in the proximal tubule and loop of Henle.
Page 24: Sodium and Water Reabsorption
Active Processes: Sodium reabsorption; dependent on sodium, water follows.
Aquaporins: Channels that facilitate water movement, regulated by ADH.
Page 25: Fine-tuning of Filtrate
Distal segments adjust reabsorption rates based on body needs.
Page 26: Reabsorptive Mechanisms
Molecular transport mechanisms involved in filtrate reabsorption, detailing nephron cell structure and processes.
Page 27: Reabsorption Rates in Proximal Tubule
Percentages of substances reabsorbed (e.g., Water 65%, Glucose 100%, Na+ 65%).
Page 28: Secretion Mechanisms
Active transport of wastes and ions from blood into nephron.
Maintains stable blood pH through H+ excretion.
Page 29: Summary of Nephron Processes
Filtration, reabsorption, and secretion contribute to urine excretion.
Page 30: Nitrogenous Wastes
Metabolic Waste Products:
Ammonia to urea conversion and purine metabolism.
Implications of excess uric acid.
Page 31: Kidney Structure Overview
Visual representation of kidney anatomy, including externals and internals.
Page 32: Anatomy of the Urinary Bladder
Key Features:
Detrusor muscle, internal/external sphincters, rugae.
Page 33: Sphincters Overview
Internal Urethral Sphincter: Involuntary control.
External Urethral Sphincter: Voluntary control from skeletal muscle.
Page 34: Regulation of Urinary System
Diuretics: Induce Na+ and water loss; effects of alcohol and caffeine.
Diuretic Medications: Target renal processes.
Page 35: Hormonal Regulation of Urine Volume
Key Hormones:
Antidiuretic Hormone (ADH)
Aldosterone
Atrial Natriuretic Hormone (ANH)
Page 36: Renin-Angiotensin System Overview
Hormonal cascade regulating blood pressure involving renin secretion in kidneys.
Page 37: Chronic Kidney Disease (CKD) Overview
Primary Causes: Hypertension and diabetes related to kidney function loss.
Page 38: Kidney Stones
Prevalence and causes related to uric acid and calcium precipitation.
Related health concerns like gout.
Page 39: Visual Representation of Kidney Stones
Diagrams illustrating kidney stone formation and impact.
Page 40: Polycystic Kidney Disease Overview
Hereditary disorder causing cyst formation and subsequent obstruction of tubules.
Page 41: Summary of Urinary System Functions
Key roles in regulation, excretion, and hormone production.
Page 42: Nephron Summary
Key functions include filtration, reabsorption, and secretion.
Page 43: Molecular Movement in Nephrons
Variations in absorption mechanisms among different substances.
Page 44: Regulation Overview
Summary of how hormones regulate kidney function and blood pressure.