Lecture Notes: Urinary System and Kidney Function

Screen and Setup

• The presentation involves a split-screen setup for visual aid: PowerPoint slides on the right and an outline on the left.
• Topic focuses on the urinary system, especially the bladder and kidneys.

Urinary System Overview

• Key Components to Understand:
  • Urinary waste origins: carbon dioxide, excess water, and nitrogenous wastes (urea, ammonia, uric acid).
  • Proteins are the primary source of nitrogenous wastes, not carbohydrates or fats.
  • Nitrogen from protein breakdown contributes to urea formation.

Organs of Filtration

• Lungs: Filter carbon dioxide.
• Sweat Glands: Assist in excreting excess salts and water.
• Liver: Processes proteins, turns parts into glucose, leftover nitrogen forms urea.
• Kidneys: Focus of current discussion.

Kidney Anatomy and Function

• Nephron Function:
  • Detailed review of nephron components.
  • Four steps of nephron function include filtration, reabsorption, secretion, and excretion.
• Hormones:
  • Role of renin and angiotensins in regulating kidney function and urine concentration.

Urinary Bladder Structure and Function

• Bladder Anatomy:
  • Inner membrane called mucosa with folds called rugae.
  • Specialized tissue: Transitional epithelium (stretches from cuboidal to squamous).
  • Wall made of smooth muscle (detrusor muscle).
• Bladder Filling and Function:
  • Absence of physical valves; physiological closure occurs via bladder stretching.
  • Ureters enter the bladder at an angle, allowing pressure to close off flow when bladder is full.
• Muscles Involved:
  • Internal urethral sphincter (involuntary, smooth muscle) and External urethral sphincter (voluntary, skeletal muscle).
  • Role of pelvic floor muscles, especially post-childbirth (Kegel exercises).

Urinary Bladder Physiology

• Micturition Process (Voiding Urine):
  • Full bladder signals brain; involuntary (medulla) signals internal sphincter to relax.
  • Voluntary control (external sphincter) learned during potty training.

Kidney and Urinary Structures for Lab

• Kidney Model:
  • Identifications: renal capsule, cortex, medulla, pyramids, papillae, minor and major calyces, and renal pelvis.
  • Renal artery and vein.
  • Location and function of nephrons.

Nephron Structure

• Blood Flow:
  • Arcuate artery and vein, afferent and efferent arterioles.
  • Peritubular capillaries reabsorb and secrete substances.
• Nephron Anatomy:
  • Bowman's capsule and glomerulus inside for filtration.
  • Proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct.

Conclusion

• The lecture covers the urinary system's structure and physiology with emphasis on the bladder and kidney components.
• The importance of understanding the physiological process in addition to anatomical knowledge.