Purpose of the gut Flashcards
1
Q
Outline the order in which food passes through the GI tract
A
- Mouth
- Oesophagus
- Duodenum of small intestine
- Jejunum of small intestine
- Ileum of small intestine
- Cecum of large intestine
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
- rectum
- anus
2
Q
What are the broad functions of the mouth?
A
- Physical breakdown of food
- Initial digestive enzymes released
- Infection control
- Saliva aids with lubrication
3
Q
What are the broad functions of the oesophagus?
A
- Rapid transport of bolus to stomach through thorax
- Upper oesophageal sphincter prevents air from entering the GI tract.
- Lower oesophageal sphincter helps prevent reflux into the oesophagus.
4
Q
What are the broad functions of the stomach?
A
- Storage
- Produces chyme through the physical and chemical breakdown of food.
- HCl provides infection control
- Secretes intrinsic factor for the absorption of vitamin B12
5
Q
What is the pyloric sphincter?
A
- A muscular sphincter found at the distal end of the stomach that releases chyme into the small intestine.
6
Q
Define chyme
A
- A fluid that passes out of the stomach that consists of gastric acid secretions and partially digested food.
7
Q
How does stomach acid help digest food?
A
- Low pH unravels proteins, increasing SA.
- This means it’s easier for proteases to break them down.
8
Q
What is the broad function of the duodenum?
A
- Neutralisation/osmotic stabilisation of chyme through HCO3 rich secretions.
- Digestion is completed through pancreatic secretions and bile.
9
Q
Where do the liver and pancreas connect to the GI tract?
A
- Through a common entrance in the second part of the duodenum.
- They are then able to deliver bile and pancreatic secretions into the gut tube.
9
Q
Where do the liver and pancreas connect to the GI tract?
A
- Through a common entrance in the second part of the duodenum.
- They are then able to deliver bile and pancreatic secretions into the gut tube.
9
Q
Where do the liver and pancreas connect to the GI tract?
A
- Through a common entrance in the second part of the duodenum.
- They are then able to deliver bile and pancreatic secretions into the gut tube.
10
Q
Why are the contents of the duodenum so hypertonic?
A
- Big molecules are broken down into many smaller molecules, increasing the osmolarity.
- This means that lots of water enters the duodenum from the vasculature.
11
Q
What is the broad function of the jejunum?
A
- Final digestion occurs here.
- Nutrient absorption - jejunum is rich in folds that increase SA.
12
Q
What is the broad function of the ileum?
A
- Water/electrolyte absorption
- Bile recirculation
- B12 absorption (terminal ileum)
13
Q
What are the broad functions of the large intestine?
A
- Final water absorption against a concentration gradient.
- Temporary storage
- Final electrolyte absorption
- Some bile salt absorption
- Production of some short-chain fatty acids
