Final answer:
Digestion starts in the mouth, where food is chewed and moistened to form a bolus before being swallowed.Food is prepared into a bolus in the mouth before swallowing.
Step-by-step explanation:
Chemical and mechanical digestion begins in the mouth, where food is prepared into a bolus, which is then swallowed. The teeth and jaw mechanically chew the food, and saliva from the salivary glands moistens the food and initiates mechanical and chemical digestion. With the help of the tongue, the food is shaped into a bolus and moved to the pharynx, where peristalsis moves the food into the stomach. Chemical and mechanical digestion commence in the oral cavity, where the process of breaking down food begins, transforming it into a cohesive mass known as a bolus.Therefore, the correct answer is:b) Bolus In the mouth, mechanical digestion is initiated by the action of teeth, which crush and grind food into smaller particles, increasing its surface area. This mechanical breakdown is complemented by the secretion of saliva, which contains enzymes like amylase that kick-start the chemical digestion of carbohydrates.
As food is mixed with saliva, it forms a soft, moistened mass called a bolus. Once the food is adequately masticated and mixed with saliva, the tongue helps shape it into a bolus, facilitating the swallowing process. Swallowing, or deglutition, involves the coordinated action of muscles to move the bolus from the mouth to the stomach through the esophagus. Contrastingly, chyme typically refers to the partially digested, semi-fluid mixture of food and digestive juices found in the stomach. Pulp is a term often associated with the soft, innermost part of fruits, and slurry typically refers to a semi-liquid mixture. In the context of digestion, bolus accurately describes the cohesive mass of food ready for swallowing after the initial processes in the mouth.