Session 1 Flashcards
What does digestion do?
Convert food to a sterile, neutral and isotonic solution that is ready for absorption
How is food processed to become small molecules?
First it is physically broken down in the act of Mastication to release large molecules. Then it is broken down chemically to release small molecules
What is Mastication?
Chewing
What does Saliva do?
Protects the mouth
Lubricates food
Starts digestion
What properties of Saliva help it protect the mouth?
Wet to keep the mucosa alive
High Ca2+ and alkaline to protect the teeth
What is a Bolus?
A ball of food that is streamlined ready to be swallowed
Where does water added to the food come from in the Duodenum?
Extra Cellular Fluid
Where does Bile added to the food come from in the Duodenum?
From the Liver and Panreas
What adaptations does the small intestine have to absorb the nutrients/fluid from food?
A brush border to greatly increase the surface area
How does the small intestine absorb nutrients?
The epithelium absorb small molecules using transport coupled with Na+ absorption.
Where do all absorbed nutrients go from the small intestine?
To the hepatic portal circulation
Why is transit in the large intestine slow?
To ensure there is maximum amount of time to absorb the last nutrients and water
How can the GI system cause dehydration?
A slight imbalance between secretion and absorption will lead to a loss of water and electrolytes from bodily fluids. eg Diarrhoea
What controls the GI system?
Neural system
Paracrine system
Endocrine system
Unusual has all 3 controls that overlap
What usually causes GI issues?
The control systems going wrong. Hard to treat due to the 2 systems overlapping
