The oral cavity, or mouth, marks the entry point of the digestive system, equipped with specialized structures for the initial processing of food.
Here, food encounters teeth and salivary glands, which work in concert to reduce food to a consistency suitable for digestion and absorption further down the GI tract.
Teeth:
The Tools for Mechanical Digestion
Teeth are hard, calcified structures embedded in the dental arches of the mouth.
They are instrumental in the mechanical breakdown of food, a process known as mastication or chewing.
Humans have two sets of teeth over their lifetime: deciduous (baby) teeth and permanent (adult) teeth.
Types of Teeth in Adults:
1. Incisors (8 total): These are the front teeth, sharp and chiseled-shaped, designed for biting and cutting food.
2. Canines (4 total): Located next to the incisors, canines are pointed and used for tearing and ripping food.
3. Premolars (8 total): Situated next to the canines, premolars have a broader surface for crushing and grinding food.
4. Molars (12 total): These are the back teeth, equipped with large, flat surfaces ideal for grinding and pulverizing food.
Tongue:
The Versatile Muscular Organ
The tongue, a muscular organ found on the floor of the mouth, plays multiple roles in the digestive and sensory systems.
Functions of the Tongue:
1. Tasting: The surface of the tongue is studded with taste buds that allow us to discern five basic tastes: sweet, sour, salty, bitter, and umami.
2. Manipulation of Food: It assists in moving food around the mouth to ensure even mixing with saliva and effective chewing.
3. Formation of the Bolus: The tongue aids in shaping chewed food into a bolus, a compact mass ready for swallowing.
4. Swallowing: It then propels the bolus towards the pharynx, triggering the swallowing process.
Salivary Glands:
Facilitators of Chemical Digestion
Role in Digestion:
These glands secrete saliva, which moistens food for easier chewing and swallowing.
Saliva contains enzymes, such as amylase, which initiate the breakdown of carbohydrates into simpler sugars right in the mouth.