Understanding the Renal and Urinary System

Sep 30, 2024

Lecture on Renal and Urine System

Objectives

  • Impact of renal function on blood pressure
  • Evaluate presentation of CKD, AKI, neurogenic, PCI, and reduction in odor-active blood

Anatomy of the Renal System

  • Components: Kidneys, ureters, renal pelvis, bladder
  • Location: Kidneys located between 12th thoracic and 3rd lumbar vertebrae
    • Right kidney slightly lower than left

Nephron: Functional Unit of Kidney

  • Role: Concentration and dilution of fluids
  • Components:
    • Renal corpuscle
    • Proximal convoluted tubule
    • Loop of Henle
    • Distal convoluted tubule
    • Collecting ducts
  • Types:
    • Cortical nephron
    • Juxtamedullary nephron

Kidney Functions

  • Glomerulus:
    • Afferent arterioles deliver blood
    • Efferent arterioles carry blood away
    • Blood filtration and regulation
  • Peritubular Capillaries:
    • Surround renal tubules and aid in reabsorption
    • Located in cortex and medulla

Renal Blood Flow

  • Blood Flow Volume: 1,000 to 1,200 mL/min
  • Cardiac Output: 20-25% filtered through kidneys
  • Glomerular Filtration Rate (GFR): Rate of plasma filtration through the glomerulus

Regulation of Blood Pressure and Renal Blood Flow

  • Auto-Regulation: Keeps GFR constant despite changes in blood pressure
    • System pressures between 80-180 mmHg maintain constant GFR
  • Tubuloglomerular Feedback: Adjusts blood flow via sodium concentration detection

Hormonal Regulation

  • Renin: Responds to low blood pressure, promotes vasoconstriction
  • Antidiuretic Hormone (ADH): Concentrates urine
  • Aldosterone: Increases sodium reabsorption, affects blood pressure

Kidney Diseases and Disorders

Urinary Tract Obstruction

  • Types: Complete or partial; structural or functional
  • Effects:
    • Dilation and risk of infection
    • Affects tubular and glomerular function
    • Can lead to scarring and tubular damage

Nephrolithiasis (Kidney Stones)

  • Risk Factors: Age, sex, race, dietary intake, medical history
  • Types: Calcium oxalate, phosphate, struvite, uric acid

Urinary Tract Infections (UTI)

  • Types: Cystitis, acute pyelonephritis
  • Common Organism: E. coli
  • Symptoms: Pain, pressure in pelvic region

Acute Kidney Injury (AKI)

  • Causes: Hypoperfusion, toxic injury
  • Classification:
    • Pre-renal: Reduced blood flow
    • Intrarenal: Tubular necrosis
    • Post-renal: Obstruction

Chronic Kidney Disease (CKD)

  • Stages:
    • Stage 1: GFR > 90, no symptoms
    • Stage 2: Mild damage, GFR 60-89
    • Stage 3: Moderate damage, GFR 30-59
    • Stage 4: Severe damage, GFR 15-29
    • Stage 5: End-stage renal disease, GFR < 15
  • Effects: Affects multiple body systems; cardiovascular, bone metabolism, immune system

Discussion on GFR and Racial Differences

  • Current practices may still show racial differences in GFR calculations
  • Recent changes in transplant eligibility criteria to remove racial bias

Summary

  • Kidney Function: Urine production, blood pressure regulation, electrolyte balance
  • Disease Impact: Can lead to comprehensive systemic effects if not managed properly
  • Effective early diagnosis and treatment crucial for urinary obstructions and renal diseases