Question

What is the cephalic phase of digestion?
A. Stimuli which causes psychological changes before the food enters the body
B. Stimuli which causes no changes before the food enters the body
C. Stimuli which causes both physiological and psychological changes
D. Stimuli which causes physiological changes before the food enters the body

Answer 1

Hint: The gastric activity of digestion is divided into three phases or stages. These three phases are the cephalic phase, the gastric phase, and the intestinal phase. Moreover, these phases overlap and occur simultaneously.

Complete answer: Before the food enters the body, a lot of physiological changes start occurring in the body. This is because the body starts preparing for the process of digestion. A reflex is generated for the same in the body which is known as the cephalic reflex. This phase is known as the cephalic phase of digestion. Even before the food enters the body, the digestive system is able to respond to the smell or the sight of the food. This is like an external stimulus. The smell and sight of the food start to cause salivation. The secretion of the gastric and the pancreatic enzymes begin. The process of digestion begins in the mouth itself. As the food reaches the mouth the taste receptors start responding. Thus, based on the above information we can conclude that the cephalic phase of digestion is the stimuli that cause physiological changes before the food enters the body.
Hence, the correct answer is option (D).

Note: The process of digestion begins in the mouth itself. This is because the mouth produces saliva as a part of the cephalic reflex for easy chewing as lubrication of the food. The cephalic reflex causes the mouth to salivate on smelling, seeing, or even listening or thinking about food. The teeth masticate and mix the food to form a bolus that can be swallowed. Due to this reason, it is advised to chew the food properly. Because if it is not chewed properly and ingested in an almost raw form then the stomach and intestines are strained to perform the process of digestion.