Week 10 (Digestive)

What are the accessory organs as opposed to the digestive tract?

Digestive Tract

• Oral cavity, pharynx, esophagus, stomach, SI and LI

Accessory Organs

• Teeth, tongue, salivary glands, liver, gallbladder pancreas

What are the 4 layers?

Mucosa:

• Epithelium, lamina propria and muscularis mucosa

Subumucosa:

• Large blood and lymphatic vessels, exocrine glands, submucous neural plexuses

Muscular Layer

• Inner circular, myenteric plexus, outer longitudinal (thickened areas - sphincters)

What is the mesentery?

• Fused double layer of the peritoneal membrane

Functions for the stomach?

• Temporary food storage

• Mechanical Digestion

• Chemical digestion (acid, enzymes)

What is the histology of the small intestine?

• Circular Folds

• Villi

  • Lacteal (primary way fat goes from digestive tract into circulation) → lacteal duct

  • Simple Columnar

• Microvilli

Functions of LI?

• Absorbas water and electrolytes

• Absorbs vitamins produced by bacteria

• Stores Feces before defecation

What can be said about the histology of LI?

• Mucosa (no villi to increase SA)

  • Protects internal laminar surface of the lumen (mucous)

• Submucosa

  • Not extending up through the villi

• Muscular Layer

  • Thinner and circular (circling around lumen of LI, outer isn’t complete anymore: teniae coli)

• Serosa (CT on superficial aspect of LI)

What is the liver for?

• Metabolic regulation

• Hematological regulation

• Bile production

What’s in the porta hepatis?

• Hepatic portal vein (sends blood to IVC)

• Hepatic artery proper brings blood

Liver filters the blood through porta hepatis.

Pathway of bile?

Made in the hepatocyte → canaliculi → ductules → interlobar bile duct → gallbladder or SI

What is special for the cystic duct?

• 2 way movement (allows to be filled if ampulla is closed)

What happens with the pancreas?

Pancreatic acini drain into pancreatic duct → accessory pancreatic duct → duodenal ampulla