Digestive System

I. Overview Diagram

A. Alimentary Canal

B. Accessory Organs

C. Digestive Process

  1. Ingestion
  2. Propulsion (swallowing and peristalsis)
  3. Mechanical Digestion (chewing, churning, segmentation)
  4. Chemical Digestion (saliva, acid and enzymes)
  5. Absorption (lymph and blood vessels)
  6. Defecation

D. Regulation of the Digestive and Absorptive Process Diagram

i. Digestive activity is provoked by a range of mechanical and chemical stimuli

ii. Controls of digestive activity are both extrinsic and intrinsic

II. Peritoneum, Blood Supply, Tunics, and Nerves

A. Peritoneum Diagram

B. Blood Supply

C. Tunics (inner to outer) Diagram

D. Nerves

III. Mouth, Pharynx (oropharynx), and Esophagus

A. Mouth Diagram

B. Pharynx and Salivary Glands

i. Pharynx - nasopharynx superior portion; oropharynx is the posterior portion of oral cavity; leads into the laryngopharynx Diagram

ii. Salivary Glands Diagram

C. Esophagus Diagram

IV. Digestion (Chewing and Swallowing) Diagram

V. Stomach (temporary storage tank and converts bolus into chyme)

A. Macroscopic Anatomy Diagram Diagram

B. Microscopic Anatomy Diagram Diagram

C. Digestive Process (Regulation of Gastric Secretion) Diagram

VI. Small Intestine (site of absorption) and Accessory Structures

A. Small Intestines

i. Macroscopic Anatomy Diagram

ii. Microscopic Anatomy

B. Liver and Gallbladder Diagram

  1. acidic, fatty chyme enters duodenum and causes release of cholecystokinin (CCK) and secretin from duodenum wall enteroendocrine cells
  2. CCK and secretin enter bloodstream
  3. bile salts and secretin transported via bloodstream stimulate liver to produce bile
  4. vagal stimulation causes weak contractions of gallbladder
  5. CCK causes gallbladder to contract and hepatopancreatic sphincter to relax: bile enters duodenum
  6. bile salts reabsorbed into blood

C. Pancreas

VII. Large Intestines    Diagram Diagram

VIII. Chemical Digestion

A. Carbohydrates

B. Proteins

C. Fats

D. Nucleic acids

Clinical Terms: