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Digestive sys
Study
| Question | Answer |
|---|---|
| Layers of the Digestive Tube | Digestive Epithelium, Lamina Propria(Basement Membrane), Submucosa, Muscularis Externa, Adventitia |
| Digestive Epithelium | Stratified Squamous ET - oral cavity, pharynx (inferior to nasopharynx), esophagus, anus; Columnar ET - most of the rest of the digestive tract |
| Lamina Propria(Basement Membrane) | Loose CT with blood vessels, nerves, lymph vessels, smooth M. Epithelium + Lamina Propria = Mucosa |
| Submucosa | Loose CT, blood vessels, lymphatics and nerve plexi. The nerves are sympathetic, parasympathetic and sensory. |
| Muscularis Externa | Smooth M: a) inner is circular, b) outer is longitudinal. Movements are coordinated by neurons of mygenteric plexus (Auerbach plexus). Sympathetic and parasympathetic nerves between Sm M layers. |
| Adventitia. Loose CT | In oral cavity, esophagus, and rectum the adventitia has high amounts of collagen that firmly attaches the tract to adjacent structures. |
| mesenteries | double sheets of peritoneal membranes; Portions of the digestive tract are suspended within the peritoneal cavity by sheets of serous membrane that connect the parietal peritoneum with the visceral peritoneum |
| peritoneal fluid | lubricates opposing parietal and visceral surfaces |
| Peristalsis | Peristalsis and segmentation are triggered by Smooth M pacesetter cells in response to chemical or physical stimulation. |
| Local peristaltic movements are triggered: | by sensory receptors in the walls of the digestive tract and by motilin ( hormone ). |