Segment 3:

Apuntes

Segment 3: Test 3 Study Guide Digestive System Key Concepts • Ingestion: The process of taking in food through the mouth. • Mastication: Chewing that mechanically breaks food into smaller pieces. • Bolus: The chewed, moistened mass of food ready for swallowing. • Chyme: A semi-fluid mixture of partially digested food and digestive juices in the stomach. Anatomy • Alimentary Canal (GI Tract): Mouth → Pharynx → Esophagus → Stomach → Small intestine → Large intestine → Anus. • Accessory Organs: Teeth, tongue, salivary glands, liver, gallbladder, pancreas. Digestive Processes • Digestion: Breakdown of food into absorbable molecules. • Absorption: Transfer of nutrients from the GI tract into blood or lymph. • Excretion: Elimination of indigestible substances via feces (defecation). Cell Types & Secretions • Parietal Cells: Secrete HCl and intrinsic factor. • Chief Cells: Secrete pepsinogen, which is activated to pepsin by HCl. • Enterocytes: Absorptive cells in the small intestine. • Brush Border: Microvilli-covered surface with digestive enzymes. • Mucous Cells: Secrete mucus to protect the GI lining. Special Structures • Villi & Microvilli: Increase ...