In human digestive system, the process of digestion starts in

In the human digestive system, the process of digestion begins in the mouth, also known as the buccal or oral cavity [4]. Digestion involves both mechanical and chemical processes. Mechanical digestion starts with mastication, where teeth break food into smaller pieces [1]. Simultaneously, chemical digestion begins as salivary glands secrete saliva containing the enzyme salivary amylase (ptyalin) [2]. This enzyme initiates the breakdown of complex carbohydrates, specifically starch, into simpler sugars like maltose [6]. While the food subsequently passes through the oesophagus, no digestion occurs there; it merely serves as a conduit to the stomach [3]. Therefore, the buccal cavity is the primary site where the initial breakdown of food components into simpler forms occurs [6].

Sources

1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 9: Life Processes in Animals > Beginning with the mouth cavity > p. 122
2. [4] Science-Class VII . NCERT(Revised ed 2025) > Chapter 9: Life Processes in Animals > Table 9.1: Action of saliva on starch > p. 124
3. [2] Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > Activity 5.3 > p. 85
4. [6] https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/digestive-system
5. [3] https://www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works