digest
42 flashcards
- 1. Ingestion & Mastication
- Consumption of solid or liquid food, Mastication: Chewing food into smaller pieces (mechanical breakdown)
- 2. Propulsion & Mixing
- Propulsion: Movement of food from one end to the other, Mixing: Movement of food back and forth to mix it with enzymes & facilitate absorption
- 3. Digestion & Secretion
- Mechanical & chemical breakdown of large molecules into smaller molecules that can be absorbed, Secretion: The addition of liquids, enzymes, and mucus to ingested foods
- 4. Absorption
- Movement of molecules out of digestive tract into blood or lymphatic system
- 5. Elimination
- Removal of undigested material, fiber, and other waste products
- Digestive Tract (GIT / Alimentary Tract)
- A long tube running from mouth to anus
- Digestive Tract components
- Oral cavity, Pharynx, Esophagus, Stomach, Small Intestine, Large Intestine, Anus
- Associated Organs
- Salivary glands, Liver, Gallbladder, Pancreas
- • 1. Mucosa
- Inner most layer; secretes mucus
- • 2. Submucosa
- Above mucosa; contains nerves, blood vessels, and small glands
- • 3. Muscularis
- Above submucosa; longitudinal, circular, and oblique muscle
- • 4. Serosa / Adventitia
- Outer most layer,
- No peritoneum
- Adventitia
- With peritoneum
- Serosa
- Peritoneum
- Layer that protects parts of the GIT
- peritoneum Visceral (Serosa)
- Serous membrane that covers organs
- peritoneum Parietal
- Serous membrane that lines the wall of the abdominal cavity
- Serous Fluid
- Enzymes: amylase, lysozyme
- a. Amylase
- Breaks down carbs
- Lysozyme
- Enzyme against bacteria
- Major salivary glands
- parotid, submandibular, sublingual
- • 1. Parotid
- Serous glands anterior to each ear
- • 2. Submandibular
- More serous than mucous; inferior to the mandible
- • 3. Sublingual
- Primarily mucous; inferior to the floor of the oral cavity
- Pharynx 3 parts
- Nasopharynx, Oropharynx, Laryngopharynx
- Esophagus
- Tube that connects pharynx to stomach, Transports food to stomach, Joins stomach at cardiac opening
- Stomach
- Located in abdomen, Storage tank of food; can hold up to 2L of food, Produces mucous, hydrochloric acid (HCl), and protein-digesting enzymes
- stomach has mucus layer that
- Lubricates and Protects epithelial cells on the stomach wall from acidic pH
- Regions of stomach:
- Fundus, body, pylorus
- • 1. Fundus
- Superior to cardiac part
- • 2. Body
- Largest part of the stomach
- • 3. Pylorus
- Funnel-shaped part of stomach; opens in 2-3 hours
- • * Cardiac Part
- Opening to stomach
- Muscles
- 1. Longitudinal (Outer), 2. Circular (Middle), 3. Oblique (Inner), Produce churning action
- • 2. Hydrochloric Acid (HCl)
- Produces a pH of about 2.0 in the stomach; kills microorganisms, activates pepsin
- • 3. Pepsin
- Enzyme for proteins; breaks down proteins into smaller peptide chains
- • 4. Intrinsic Factor (IF)
- Binds to Vit. B12 for absorption (DNA synthesis, RBC production)
- Digestive process
- Digestion, Absoption, Transportation
- • 1. Digestion
- Mechanical / Chemical
- • 2. Absorption
- Movement of molecules from GIT to blood / lymphatic system
- • 3. Transportation
- Movement of digestion
- Pharynx (throat)
- Connects mouth to esophagus