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Phys4 GI Intro
Phys4 Overview of GI function
Question | Answer |
---|---|
3 main phases of digestion | 1.Cephalic (food outside the body, senses are stimulating activation). 2.Gastric (food in the stomach). 3.Intestinal (chyme moving through the Intestines, abrosorption). **All 3 are ALWAYS ongoing. |
Cephalic phase of digestion | The senses (sight, smell, thought, sound) trigger responses in anticipation of food: 1.Salivation. 2.Vagal activation of Orad & Cuadad stomach, pancreas, liver, and GB. |
What are the 3 main functions of saliva | 1.Lubrication. 2.Protection. 3.Digestion. |
Main contents within saliva | 1.Enzymes (amylase for carb digestion). 2.Mucous. 3.Bicarb. 4.Antibacterial agents. |
Main stomach secretions | 1.Pepsin. 2.Acid. 3.IF. 4.Mucous. 5.Hormones. |
Functions of the Orad Stomach | Upper part of stomach that: 1.Accomadates. 2.Digests. 3.Delivers to small intestine. |
Functions of the Caudad Stomach | Lower part of stomach 1.Mix. 2.Grind. 3.Deliver to small intestine. |
Do they Orad and Caudad stomach work together? | YES, they both help to deliver food to the small intestine. |
Main Pancreatic secretions | EXOCRINE PANCREAS secretes: 1.Digestive enzymes. 2.Bicarb. |
Main liver/GB secretions | 1.Bile. 2.Bicarb. |
Key sensory receptors found in the GI | 1.Stretch. 2.pH. 3.Osmolality. 4.Chemo. **contribute to regulation hormone release. |
Where will you find striated muscle in the GI? | 1.Pharynx. 2.Upper Esophagus. 3.External Anal Sphincter |
What is the difference b/w Intrinsic and Extrinsic nervous systems in the GI? | EXTRINSIC: the SNS & PNS which modulate the Intrinsic system. INTRINSIC: (Enteric) is w/in the gut wall and serves as the "brain" of the GI. It initiates neural signals & motility, adjusting function on its own. |
Where all do the GI sensors in the duodenum send signals to? | They send neural & hormonal signals to: 1.Pancreas. 2.Liver. 3.GB. 4.stomach. **These neuronal reflexes influence secretions & motility. |
Main function of Small Intestine | 1.Primary site for absorption & digestion. 2.Majority of WATER absorption. **Mostly completed by the end of jejunum. |
What does the Iliocecal reflex influence? | Gastric emptying and motility. **If it is stimulated by passing food, it signals to stop emptying and fod delivery. |
Main function of Large Intestine | 1.Absorbs water and electrolytes. 2.Packs & Evacuates (biggest job) |