Mechanical and Chemical Digestion

Defn. of Digestion: the process whereby a biological entity processes a substance, in order to chemically convert the substance into nutrients. It usually involves mechanical manipulation and chemical action.

Mechanical Digestion

What is it?

This type of digestion involves the mixing, grinding or crushing of large pieces of food into smaller places.

Why does it take place?

So that the food we consume is broken down into smaller pieces before we swallow it which in turn makes process of chemical digestion - that takes place later on - more effective because it works more efficiently on smaller surface areas.

Where does it take place?

In animals, this digestion takes place in the mouth.

The process?

We rip away the food with our canines, bite it into small chunks with our incisors and grind the food with our molars/pre-molars. This process stimulates the exocrine glands in the mouth to release digestive enzymes such as salivary amylase, which aids in the break down of the food, particularly carbohydrates. Chewing the food also causes the release of saliva, which helps condense food into a bolus that can be easily passed through the esophagus to the stomach.

When?

This is the very first part of the digestion process, so it happens right at the beginning whenever we take in any amount of food.

Chemical Digestion

What is it?

This is when the main breakdown of the food we consume takes place in order to sufficiently obtain all the nutrients, minerals and vitamins from that food.

Where does it take place?

Mainly in the later parts of the alimentary canal, such as: the stomach, the small intestine, the large intestine but also with the assistance of other organs like the liver and pancreas.

The process?

In the stomach the food is churned and thoroughly mixed with acid and other digestive enzymes with digestive fluid to further decompose it chemically. Gastrin is the hormone in the stomach that kindles the gastric glands to secrete pepsin and HCL. More

...