Question

Where does digestion begin?

Answer 1

The process of digestion involves breaking down large, insoluble food molecules into smaller molecules that can be absorbed into the bloodstream. Many digestive fluids and enzymes are used in this process, including saliva, mucus, bile, and hydrochloric acid, among others.

Complete answer:
Digestion begins the moment food is placed in the mouth. Chewing breaks down food into smaller pieces, allowing enzymes to access more surface area. Saliva contains salivary amylase, an enzyme that breaks down starch into small sugar molecules. Because the food remains in the mouth for a long time, only about 5% of the starch is fully broken down. Salivary amylase continues to work until the stomach's strong acid content deactivates it. The lingual lipase enzyme is secreted by cells at the base of the tongue to start the fat digestion process.
The human body's food digestion process is divided into four stages:
1. Food enters the body through the mouth, travels through the stomach, and then into the small intestine, where it is digested.
2. Through small pores in the small intestine, nutrients from digested food are absorbed into the bloodstream.
3. The undigested food is sent to the large intestine, where any unprocessed water or nutrients are reabsorbed.
4. Stools carry the remainder of the waste food product out of the body.

Thus, digestion begins from the mouth.

Note:
Digestive systems come in a variety of shapes and sizes. Internal digestion and external digestion are fundamentally different. External digestion evolved earlier in evolutionary history, and it is still used by the majority of fungi today. Enzymes are secreted into the organism's environment, where they break down organic material, with some of the products diffusing back to the organism.