PHIS 206 Lecture Notes - Lecture 23: Gastrointestinal Tract, Venous Blood, Serous Membrane
2 May 2018
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Lecture 23: Intro to GI
Digestive System
• Purpose: Transfer nutrients, H2O, and electrolytes from diet into internal environment of
body
• Another blood conditioner (kidneys, lungs)
• Technically anything in your gi tract/tube thingy is outside of the body o:
Bits and Pieces
• Consists of the digestive tract (alimentary tract)
• → Tube & doors (sphincters) to segregate portions of tube
• AND several accessory organs
Accessory Organs
• Salivary Glands
o Add secretions to lubricate and begin digestion of oral contents
• Exocrine Pancreas
o Adds secretions to continue digestion of intestinal contents
• Hepatic/Biliary System
o 1. Create and secrete bile into intestinal contents to enable proper lipid handling
o 2. Receives nearly all blood coming from gut via portal system for initial
processing
▪ Gallbladder stores bile (liver makes it??)
▪ Bile encourages the fats to behave better in the aqueous solution → bile is
what helps with fat
Blood Flow
• Portal System
o Venous blood draining from stomach and intestine travels to liver before joining
systemic venous drainage
o Liver also receives arterial blood
• Liver has hella blood
Layers of the Gut
• Four main layers
o Serosa
▪ Tough fibrous exterior layer, helps lubricate any movement
o Muscularis Externa
▪ Two layers of muscle (three in stomach) that serve to manipulate the
contents of the gut lumen
o Submucosa
▪ Connective Tissue Layer
o Mucosa
▪ High Surface Area → possesses machinery for absorption and final
digestion
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Document Summary
Digestive system: purpose: transfer nutrients, h2o, and electrolytes from diet into internal environment of body, another blood conditioner (kidneys, lungs, technically anything in your gi tract/tube thingy is outside of the body o: Bits and pieces: consists of the digestive tract (alimentary tract, tube & doors (sphincters) to segregate portions of tube, and several accessory organs. Accessory organs: salivary glands, add secretions to lubricate and begin digestion of oral contents, exocrine pancreas, adds secretions to continue digestion of intestinal contents, hepatic/biliary system, 1. Create and secrete bile into intestinal contents to enable proper lipid handling: 2. Receives nearly all blood coming from gut via portal system for initial processing: gallbladder stores bile (liver makes it??, bile encourages the fats to behave better in the aqueous solution bile is what helps with fat. Blood flow: portal system, venous blood draining from stomach and intestine travels to liver before joining systemic venous drainage, liver also receives arterial blood, liver has hella blood.
