ANATOMY

Detailed explanation-1: -Food is taken into the mouth where it is physically broken down by the teeth into smaller pieces. The presence of food in the mouth triggers a nervous reflex that causes the salivary glands to deliver a watery fluid called saliva to the mouth.

Detailed explanation-2: -Ingestion is a process where food is taken in through the mouth and broken down by teeth and saliva. Ingestion is the first step in the process of digestion.

Detailed explanation-3: -Ingestion can be referred to as an organism’s consumption of a substance. In the case of human beings, when the food is taken in from the mouth and then masticated and swallowed for further processing, it is called ingestion. It takes place by absorbing substances by cell membranes in single-celled organisms.

Detailed explanation-4: -In single-celled organisms ingestion takes place by absorbing a substance through the cell membrane. Besides nutritional items, substances that may be ingested include medication (where ingestion is termed oral administration), recreational drugs, and substances considered inedible, such as foreign bodies or excrement.