Digestion and enzymes
The digestive system
Processes of digestion
1) Ingestion - The process of taking food in e.g putting food in your mouth
2) Digestion - The process of breaking down large insoluble molecules into smaller more soluble ones, this occurs in the mouth, stomach and small intesting
3) Assimilation - Occurs when food molecules become part of the body tissue
4) Absorption - The process of small soluble molecules passing across the small intestine wall and into the blood or lymph systems
5) Egestion - The process of passing out undigested material from the anus.
There are two ways of breaking food down during digestion these are
1) Mechanical digestion - e.g chewing
2) Chemical digestion - e.g enzymes breaking down nutrients
Where digestion occurs
The buccal cavity/ mouth
Food enters the body through the buccal cavity (ingestion). The food is chewed (mechanical digestion) and mixed with saliva. Saliva is made in the salivary glands and contains a carbohydrase enzyme called amylase. This begins to digest starch into simpler sugars like maltose (chemical digestion).
It's job is to pass the chewed food down to your stomach. The oesophagus has longitudinal and circular muscles in it's wall. The muscles contract and squeeze in behind the bolus (chewed food) to push it away. This process is called peristalsis.
The stomach is a muscular…