The Digestive Tract

The digestive tract plays the role of digesting and absorbing food. Once one has eaten,
the brain and hormones help various organs in the digestive tract to break down the food eaten
into components that can be absorbed. The digestive tract extends from the mouth to the anus.
After food is broken down into smaller components, the digestive tract helps in the absorption of
nutrients. The components of the digestive system include the mouth, throat, esophagus,
stomach, small intestines, large intestines, and rectum (Sizer, & Whitney, 2017) .
The Mechanical Aspect of Digestion
The mechanical digestion of bread starts at the mouth. After taking a bite, the solid pieces
of bread are broken down into smaller pieces by the teeth. Chewing helps ensure that the bread is
broken down into smaller pieces that can be swallowed without choking. The process of chewing
also ensures that the water is added to the bread. Through the addition of water, the bread
becomes softer (Crash Course, 2012). During the process of chewing, salivary glands release
saliva that is mixed with the food, and this eases the process of swallowing. After the process of
chewing is complete, one swallows the food. Swallowing forces the chewed bread to the
esophagus. When one is swallowing, the epiglottis helps in closing down the trachea and, in so
doing, prevents the food particles from entering the trachea. Once the chewed bread lands in the
esophagus, the walls contract to push food into the stomach.
A wavelike squeezing of the esophagus called peristalsis helps ensure that food is pushed
down the esophagus into the stomach. In the stomach, the muscles of the stomach mix the food
with digestive juices and hold the food until it can be digested. At this point, the bread is now

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referred to as chyme. The exit of the chyme from the stomach is controlled by the muscular
pyloric valve. The pyloric valve ensures that chyme moves a little at a time into the small
intestines. After a few hours, all the chyme is emptied into the small intestine. The small
intestine plays the role of absorbing nutrients (Crash Course, 2012). Then food then moves to the
large intestine where water is absorbed. Minerals are also absorbed in the small intestines. Other
undigested materials form feces that have to be excreted. The undigested material is stored in the
rectum. The rectum acts as the holding area for the undigested matter that is later passed out
through the anus.
The Chemical Aspects of Digestion
The main distinction between the chemical aspect and the mechanical aspect is the fact
that the chemical aspect involves enzymes that are secreted in the digestive system, while the
mechanical aspect involves muscles. Chemical digestion involves enzymes that are secreted in
various parts of the digestive tract. The enzymes help break down the bonds that bind food
particles together. In the mouth, food is mixed with saliva. Saliva contains an enzyme that starts
breaking down starch. Another enzyme in the saliva initiates the digestion of fat. Saliva is also
important since it helps in the maintenance of healthy teeth. Saliva washes away the food
particles that would otherwise decay and destroy the teeth. Saliva also ensures that it neutralizes
decay-promoting acids.
In the stomach, the digestion of proteins begins. The stomach walls release gastric juice
that is a mixture of water and various enzymes. The stomach also releases hydrochloric acid. The
acid is required to activate enzymes that digest proteins. Pep[sin enzyme helps in the digestion of
proteins. Lipase helps in breaking down triglycerides. The main function of the stomach is to aid
in the digestion of proteins. Enzyme amylase that helps in the digestion of starch in the mouth

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cannot continue in the stomach due to the pH levels. The stomach has a pH of between 2.0 and
3.0, indicating it is highly acidic. The stomach also releases mucus that coats the digestive wall
and prevents corrosion by the acid. Minor digestion of lipids takes place in the stomach. In the
duodenum, bicarbonate helps in neutralizing the acid secreted in the stomach. In the small
intestine, fat is also broken down. Bile that is manufactured by the liver and stored in the gall
blander helps in the digestion of fats. The food is then absorbed in the small intestine.
A  Letter From Your Digestive Tract
There are many digestive disorders that result from certain foods. One of the disorders
relates to intestinal gas. Milk intake can result in intestinal gas for people who cannot be able to
digest the milk sugar lactose. The solution lies in ensuring that one does not exceed 4 ounces of
milk at a sitting. Beans can also cause gas, and the solution lies in eating rinsed canned beans.
One should also ensure that they slow down the process of eating to ensure that they do swallow
gas. One also needs to ensure that they eat roughages to prevent constipation (Sizer, & Whitney,
2017).

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References

Crash Course. (2012, August 6). The digestive system: Crashcourse biology #28  (Links to an
external site.) [Video file]. Retrieved from
http://www.youtube.com/watch?v=s06XzaKqELk
Sizer, F. & Whitney, E. (2017). Nutrition: Concepts and controversies (14th ed.). Mason, OH:
Cengage Learning.