Download Mechanical and Chemical Digestion

Mechanical and Chemical Digestion
By Smarty — One of many Digestive blogs on SmartLivingNetwork.com
The Digestive System's Biological Function
The digestive system is of vital biological importance to the body. Without the ability to process foods,
extract nutrients, and eliminate waste, every part of our body would cease to function. All food eaten
must be digested, nutrients absorbed, and unnecessary or harmful agents eliminated from the body.
Digestive System: The Food Journey
Our Mouth: Believe it or not, the mouth will prepare for digestion before food even enters. Just the
smell, sight, or sound of food is enough to trigger saliva glands into action. This is important because
the chemicals in saliva work with the mechanism of the tongue and teeth to break down food in a
way that both prepares it for the next steps and ensure optimal absorption of nutrients.
The Pharynx: Once food has been put through the chemical and mechanical digestion occurring in the
mouth, it's time to make its way down to the stomach. To get there, the tongue and soft palate work
together to push food back, closing off our trachea and passing it through our throat (otherwise known
at the pharynx) - another good reason to make sure food is broken down!
The Esophagus: After passing through the pharynx, food enters the esophagus and is pushed through
a series of involuntary contractions (called "peristalsis") toward the lower esophageal sphincter
otherwise known as LES. It is this sphincter that malfunctions in conditions like GERD
(Gastroesophageal Reflux Disease) or heartburn.
The Stomach: Finally, the food has reached the stomach. With strong muscular walls the stomach acts
as mixer and grinder, mechanically digesting our food while its acids and enzymes work to
chemically digest it. In the end, our food is reduced to nothing more than nutritious liquid and small
solid remnants.
The Small Intestine: After passing through the stomach, it's on to the small intestine where the
nutritious liquid and small solid remnant are exposed to even more chemical digestion via enzymes
from the pancreas and bile from the liver as peristalsis (the same involuntary contractions which
occur in the esophagus) forces the food along its way. It is at this point that our body finally receives
the nutrients from our food via the bloodstream, while the remainder makes it way to the colon.
The Colon: The final stop in our food’s journey through our digestive system, the colon’s job is to
remove liquid from the non-nutritive food waste until it becomes solid and ready for excretion. By the
time our food is ready for the toilet, it’s been approximately 36 hours since it originally entered our
mouth.
What is Mechanical Digestion?
Mechanical digestion is simply the aspects of digestion achieved through a mechanism or movement.
There are two basic types of mechanical digestion.


Chewing: The first step when it comes to digestion actually begins as soon as food enters the
mouth. Chewing begins the process of breaking down food into nutrients. As a type mechanical
digestion, chewing our food is an important part of the digestive process because smaller pieces
are more readily digested through chemical digestion.
Peristalsis: Mechanical digestion also involves the process known as peristalsis. Peristalsis is
simply the involuntary contractions responsible for the movement of food through the
esophagus and intestinal tracts.
What is Chemical Digestion?
Chemical digestion is much like it sounds – those aspects of digestion achieved with the application
of chemicals to our food.
Digestive enzymes and water are responsible for the breakdown of complex molecules such as fats,
proteins, and carbohydrates into smaller molecules. These smaller molecules can then be absorbed for
use by cells.
The presence of these digestive enzymes accelerates the digestion process, where absence of these
enzymes slows overall reaction speed. Currently, there exist eight digestive enzymes mainly responsible
for chemical digestion.
The digestive system is also associated with many accessory organs responsible for producing an array
of chemical enzymes: salivary glands, pancreas, liver, gallbladder.
A Necessary Equilibrium: Mechanical and Chemical Digestion
There exists a natural equilibrium in your body for mechanical and chemical digestion. Mechanical
digestion preps food for chemical digestion as smaller pieces are more readily broken down and
absorbed. The enzymes necessary for proper chemical digestion are also in equilibrium. The accessory
organs of the digestive system necessary for the production of these enzymes must all work in a
harmonious fashion to accomplish proper digestion.