Factors of Digestion

There are several factors of digestion. These are as follows:
1. Mechanical factors:
a. Prehension: Prehension means to grasp or to hold off and taken into mouth. Different species has different prehensile techniques and prehensile organs as well. These includes lips, teeth, tongue, forelimb, snout, claws etc.


b. Mastication (Chewing): Mastication means to make particles into smaller pieces. During mastication salivation is increased which helps to make bolus formation for easy swallowing.


c. Deglutition: deglutition is the process of swallowing of boluses to the stomach through the pharynx and esophagus. It is a complex reflex act.


d. Regurgitation:
The return of undigested material from the stomach to the mouth called regurgitation. Regurgitation is noted in ruminants and in certain birds such as
owls. Unlike emesis, regurgitation is a normal physiological component of animals digestive process.
e. Rumination (Cudding): The process in ruminants whereby contents of the reticulorumen are regurgitated for remastication. This assists fermentative digestion in the rumen by reducing the particle size of the rumen contents and by stimulating salivation. This cud is chewed for about 40 seconds, with the addition of saliva. Eructation may occur during this time without interrupting the chewing. Then the bolus is swallowed and returns to the reticulum, be followed, a few seconds later, by the regurgitation of another bolus.

f. Vomiting: It is a protective reflex that makes it possible to eject any harmful, toxic or irritating substances from the stomach. It is also caused by the mechanical irritation of pharynx or by disturbance in the semicircular canals of the ears. Vomiting centre is located in the medulla. It acts largely through respiratory centre.

g. Belching: Belching is the process of the churning of food materials in the rumen.

h. Peristalsis: It is a propulsive movement of intestine.

i. Defecation: It is a process by which feces is expelled out from rectum through anus.

2. Secretory and chemical factors:
a. Activities or work of digestive glands.

b. Enzymes and HCl acid.
3. Microbial factors: Fermentation by bacteria and certain species of protozoa.

Posted in: Physiology