Digestive System and Urinary System Lecture

Pancreas Overview

• Second largest gland; first largest is the liver.
• Two main types of cells:
  • Exocrine (Acinar) Cells:
    • Secrete enzymes into ducts.
    • Ducts converge into a duct joining the bile duct, then into duodenum.
    • Examples of pancreatic enzymes: Chymotrypsinogen, Trypsinogen.
  • Endocrine (Islets of Langerhans) Cells:
    • Scattered among acinar cells, more in the tail of the pancreas.
    • Types of islet cells:
      • Alpha cells: Secrete glucagon (raises blood sugar).
      • Beta cells: Secrete insulin (lowers blood sugar).
      • Delta cells: Secrete somatostatin (inhibits other hormones).

Pancreas Anatomy

• Located between stomach and duodenum.
• Parts of the pancreas: head, neck, body, tail.

Urinary System Overview

• Designed to form urine and excrete it.
• Components:
  • Two Kidneys: Form urine.
  • Two Ureters: Transport urine.
  • Urinary Bladder: Stores and possibly concentrates urine.
  • Urethra: Conveys urine to exterior.

Kidney Anatomy and Function

• Size: 4-5 inches long, 2-3 inches wide, 1 inch thick.
• Location: Posterior abdominal wall, retroperitoneal.
• Right vs. Left Kidney:
  • Right kidney lower due to the liver.
  • Left kidney spans T12 to L3 vertebrae.

External Structure

• Bean-shaped with a hilum.
• Vascular supply:
  • Renal Artery: From abdominal aorta.
  • Renal Vein.
  • Renal Pelvis: Leads to ureter.

Internal Structure

• Cortex and Medulla.
• Mass of tubules: secretory and excretory.

Nephron: Structural and Functional Unit

• Components:
  • Bowman's Capsule: Parietal (outer layer) and visceral (inner layer with podocytes).
  • Glomerulus: Capillary bed within Bowman's capsule.
  • Renal Tubules: Proximal convoluted tubule, Loop of Henle, Distal convoluted tubule.

Nephron Function

• Formation of glomerular filtrate.
• Blood supply and filtration:
  • Afferent arteriole: Supplies blood to glomerulus.
  • Efferent arteriole: Carries blood away.
  • Glomerular filtration through capillary endothelium, podocytes, basement membrane.

Tubular Reabsorption and Secretion

• Proximal Convoluted Tubule: Absorbs water, glucose, amino acids, sodium, vitamin C.
• Loop of Henle:
  • Descending limb reabsorbs water.
  • Ascending limb reabsorbs sodium and chloride.
• Distal Convoluted Tubule: Absorbs water, calcium, phosphate, sodium; secretes hydrogen and potassium ions.

Blood Flow and Filtration in Kidneys

• 1,200 cc of blood per minute.
• 125 cc glomerular filtrate per minute; 124 cc reabsorbed.
• Final urine output: 1 cc per minute.

Slides and Visuals

• Pancreas Position: Shows head, body, and tail.
• Islets of Langerhans: Staining differentiation.
• Kidney Cortex: Glomerulus, Bowman's capsule, proximal tubules.
• Blood Supply and Tubule Structure: Shows afferent/efferent arterioles and loop of Henle.

Additional Context

• Pancreatic cancer discussion.
• Importance of anatomical knowledge in clinical settings.
• Historical anecdotes about kidney function and medical experiences.

End of Lecture Notes.