MMED1005 Lecture Notes - Lecture 12: Chymotrypsin, Lactase, Circulatory System
Whats i these letures?
- Functions and organisation of the gut
- Gross anatomy
- Finer structure
- Gut motility – how it works
- The mucosa
- Stomach, gastric acid
- Pancreas and digestion
- Bile and the digestion of fats
- Portal circulation and the liver
- Colon and fluid movements
Overall process:
- Start following the food as it moves down the oesophagus and into the stomach
- Stored in the stomach, mixed with gastric acid and pepsin
- Broken down, squirted into the duodenum and neutralised in the duodenum by the
pancreatic juice
- Pancreatic enzymes are added
- The digestive process starts
- Bile is added for the digestion of fats
- Digested products are absorbed by the epithelial cells through transporters
- Digested products go into the hepatic portal vein and to the liver
- And then colon and fluid movements
**note: pay attention to the portal circulation
Generally, the layers of the gut wall are similar: outer→inner (lumen)
- Outer layer of membrane – serosal membrane
- Longitudinal muscle
- Myenteric plexus
- Circular muscle
- Submucous plexus
- Submucosa
- Mucosa
But, differently adapted for different functions. E.g. oesophagus: designed for maximum
speed, stomach: top part is a sack; lower part is a pump; sanitisation, small intestine: all
about digestion and absorption, colon: a safety net – youe asored eerything in the
small intestine and the colon is there to absorb the last of the fluid etc. and allow bacteria to
reak do aythig e eret ale to ad release ost of it as short haied fatty aids –
acetate, propionate and butyrate
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Document Summary
Start following the food as it moves down the oesophagus and into the stomach. Stored in the stomach, mixed with gastric acid and pepsin. Broken down, squirted into the duodenum and neutralised in the duodenum by the pancreatic juice. Bile is added for the digestion of fats. Digested products are absorbed by the epithelial cells through transporters. Digested products go into the hepatic portal vein and to the liver. Generally, the layers of the gut wall are similar: outer inner (lumen) Outer layer of membrane serosal membrane. Yes, roughly, e. g. ~1. 5l of food and ~1. 5l of drink. Most of this ~9l is absorbed by the small intestine, some go to the colon where most of the remaining fluid is absorbed, the small amount remaining is lost in faeces. We absorb stuff in the small intestine, tiny bit in the stomach (e. g. aspirin, ethanol), some in the colon.