Difference between Chemical and Mechanical Digestion
Mechanical digestion involves physical breakdown of the foods while chemical digestion
involves breakdown of the chemical components of the foods.
In mechanical digestion, the food undergoes physical changes as goes through the
digestive system. For instance, the solid food like apple when chewed is turned into small pieces,
changes the shape, color, and consistency, crushed and is turned into bolus. Once swallowed and
moving through the digestive tract, that apple within the digestive system is further broken down
and become semi liquid or liquid as it undergoes the digestive processes.
While the physical characteristics of food changes during mechanical digestion, there are
also many chemical changes happening in the food. During digestion, the components of the
food mix up with water and enzymes and produces different chemical reactions breaking down
the substances into simpler forms so they can be absorbed and used by the body. For instance,
simple chemical digestion happens in the mouth when simple carbohydrates are broken down as
the food mixes up with the saliva which contains the enzyme ptyalin or amylase. The enzymes
amylase facilitates chemical digestion which changes complex sugar such as maltose into forms
with simpler units like glucose (Structures of Human, n.d.). The enzyme lipase on the other hand
break down fats into glycerol and fatty acids while pepsin facilitate breaking down of protein
into smaller fragments and ultimately into amino acids.
Mechanical digestion generally makes food easy to swallow and travel within the
digestive system. The process prepares the food particle into shape or form that will facilitate
chemical digestion. Chemical digestion on the other hand is in charge of making changes so the
chemical contents of the food can be absorbed and used by the body.
Reference
(n.d.). Structures of Human. Retrieved November 22, 2011, from
http://www.johnmccraess.ocdsb.ca/Teachers/Box/DigestionWeb/PhysChemlDigest.html