Digestive System

Secretes chemicals and primary location of absorbing biomolecules

Small Intestine

Fundamentals:=

• Bulk of chemical digestion
• Chemicals (Intest&Panc) are the key to proper digestion and absorption
• Important in mechanical digestion of lipids

Function/Purpose:

• Biomolecule Absorption
• Secretion of CCK
• Biomolecule Synthesis
  • Lipid resynthesis of triacylglycerides from fatty acids and monoacylglycerols

Salient Enzymes and Function Tests:

Enzymes:

• Enteropeptidase/Enterokinase/Master Switch
  • Activates trypsiogen and trypsin

Enterogastrones - slow the movement of chime and allow a greater time to digest the fat

• Secretin
• Cholecystokinin (CCK) - secreted
  • Triggers the release of Bile into the small intestine
  • Triggers the release of Pancreatic Juice

Disaccharidases

• Maltase - converts maltose into glucose
  • Surface of intestinal cells
• alpha-Glucosidase - digests maltotriose and other oligosaccharides
  • Surface of intestinal cells
• Sucrase - digests sucrose (GLU and FRU) disaccharide
  • Surface of intestinal cells
• Lactase - converts lactose into GAL and GLU

Peptidases

• Dipeptidase - cleave the peptide bond of dipeptides to release the AA’s

Stomach Function Tests and Assessment:

Anatomy:

Gross Anatomy:

• Duodenum - most digestion occurs
• Illeum
• Jejunum

Micro Anatomy:

• Inner Wall
  • Villi
    • Microvilli
• Epithelial Cells
• Blood Vessels
• Lymphatics
• Circular Muscle
• Longitudinal Muscle
• Smooth Muscle

Regulation:

• PNS-ANS inhibits the digestion

Concept:

• Pancreatic Juice - Pancreas
• Biomolecules
• Surface Area and Convolutions
  • Volume - Surface area and Length
• Tissue difference btwn Small and Large Intestines
• Nervous System
• Endocrine System
• Peristalisis and Endocrine and Nervous System
  • Endocrine
    • Hormones influence epithelial and endocrine cells
  • Nervous System
    • Parasympathetic Nervous System - innervates the peristalisis
      • electrical continuity imposed by Gap Junctions of circular & longitudinal muscles

Terminology:

• Peristalisis: quick and unconscious gastrointestinal contractions of Smooth Muscle

Additional Information:

• Wikiedia
• Clinton Community College
• Duodenum