Digestion- Sarah Wakelin Flashcards
Name two types of Digestion
Mechanical and Chemical digestion
Complex insoluble food particles are broken down to form….
Simple soluble nutrients
Why do smaller food particles have a larger surface area?
For digestive enzyme action to break them down further into simple molecules
What are the 4 main parts of Mechanical digestion?
The chewing process(mastication)
Bolus formation
Churning movements
Peristaltic movements
What occurs in the chewing process/ mastication?
Food is broken down into smaller particles by the teeth and tongue.
What occurs in the bolus formation?
The chewed food is mixed with saliva and rolled into a ball of food (bolus) using the tongue. The swallowing process starts with the tongue pushing the bolus through the pharynx, from where it enters the oesophogus.
What occurs during the churning movements?
The stomach wall contracts and relaxes, causing churning movements . Food particles are broken down further for effective action and thoroughly mixed with gastric juice.
Describe peristaltic movements
This is the rhythmic contractions and relaxation of the muscle wall in the alimentary canal.
It helps move the food particles forward through the entire length of the alimentary canal.
Chemical digestion
the breaking down of large, insoluble molecules in food into smaller, soluble molecules by the addition of water
Hydrolysis
Catabolic reaction where large insoluble ,molecules are broken into smaller, soluble molecules by the addition of water
What do hydrolic reactions need in order for them to catalyse?
Enzymes
Role of water during digestion
- Lubricant and facilitates chewing and swallowing
- Solvent for digested food
- Transports digested food
- Medium in which digestive reactions occur
- Reagent for hydrolysis
