Structure and Processing of the Digestive System

This report discusses the structure and processing of the digestive system, including the role of the gastrointestinal tract and accessory organs in digestion. It covers the processes of ingestion, digestion, absorption, assimilation, and defecation. The report also highlights the importance of the digestive system in converting food into nutrients and energy for the body to function properly.

Task 24 Timed assessment

Contents
INTRODUCTION...........................................................................................................................1
MAIN BODY...................................................................................................................................1
Structure and processing of the digestive system........................................................................1
CONCLUSION ...............................................................................................................................3
REFERENCES................................................................................................................................4

INTRODUCTION
The process of digestion involves breakdown of food into smaller components to
facilitate absorption and assimilation in the entire body. Digestion is a complex process that
converts the food into nutrients for the body to use as a source of energy, cell growth and repair.
The waste produced is eliminated through this process. The human digestive system is composed
of the gastrointestinal tract along with the accessory organs of digestion (Fang and et. al., 2020).
There are three phases associated with the process of digestion: cephalic phase, gastric phase and
the intestinal phase. This report highlights the structure of the digestive system and its
association with ingestion, digestion, absorption, assimilation and defecation.
MAIN BODY
Structure and processing of the digestive system
The unique construction of the digestive system is done in a way that the food is
converted into nutrients and energy. The breakdown of the food into nutrients energy production
and growth of cells enables the body to stay healthy and function properly (Niehaus and Mora,
2022). The digestive system constitutes of the mouth, oesophagus, stomach, small intestine, large
intestine, rectum and anus. The pancreas, gall bladder and the liver are accessory glands which
help the processing of food along the way. The working of digestive system is given as follows: Ingestion: The process of digestion starts in the mouth itself. The salivary glands are
activated as soon as food enters the mouth. The food is mixed with the saliva which
ensures the breakdown of the food for absorption of nutrients. The presence of the food in
the surrounding environment produces a nervous reflex which activates the salivary
glands to produce saliva inside the mouth (Cholewińska, Czyż, Nowakowski and
Wyrostek, 2020). Food ingested is made slippery with the help of mucin, for smooth
swallowing. The tongue helps in movement of the churned food towards the oesophagus
and into the throat. This process is termed as ingestion.
 Digestion: The oesophagus receives food from the mouth with the help of a small flap
called epiglottis, which prevents the swallowed food from entering the windpipe. This
entry of food is followed by a series of muscular contractions called peristalsis which
helps in delivery of food to the stomach (Lobo-da-Cunha, 2019). The sphincter is a ring-
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like structure which relaxes to facilitate entry of food inside the stomach and also to
prevent the back flow of contents of the stomach into the oesophagus.
Source: <https://courses.lumenlearning.com/suny-ap2/chapter/overview-of-the-digestive-system/
>
The stomach is a J-shaped organ which continues the process of breakdown of food with
the help of powerful enzymes. There is a strong acid that covers the lining of the stomach to kill
any harmful microorganism that might have entered the body through food. The food is reduced
into a mass called chyme (Tao and et. al., 2020). The chyme is passed down to the bottom part of
the stomach or the duodenum of small intestine, which is supplied with fluids rich in bile salts
and digestion enzymes. These fluids helps in lubricating the partially digested food and move it
down the gut.
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Illustration 1: Structure of the digestive system

 Absorption: Upon breakdown into smaller particles, the process of absorption starts in
the small intestine itself, with the presence of millions of small finger like structures
called villi that cover the lining of the small intestine (Lynch and Buckin, 2022). When
the digested food comes in contact these villi, rapid absorption of nutrients takes place in
the bloodstream.
 Egestion: Egestion is the removal of undigested material from the body. By the time the
food reaches the end of small intestine most of the important nutrients and minerals are
already absorbed that are useful for the body (Khoa and et. al., 2021). The only remaining
component is water mixed with cellulose, which are passed to the large intestine. The
recovery of water and electrolytes along with fermentation of indigestible food for
example, undigested carbohydrates (fibre) with help of bacteria takes place in the large
intestine. There is also formation and storage of faeces inside the large intestine which
are then accumulated inside the rectum eventually leading to its evacuation through anus
(Zumbach, von Kotzebue and Pirklbauer, 2022).
CONCLUSION
From the above report, it can be concluded that the digestive system is necessary for the
breakdown of food into smaller components for effective absorption of nutrients and minerals.
There are various processes such as ingestion, digestion, absorption and egestion that are
involved in the working of digestive system. The digested food is used as a fuel for the body to
be able function in an efficient manner.
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REFERENCES
Books and Journals:
Fang and et. al., 2020. Manifestations of digestive system of hospitalized patients with
coronavirus disease 2019 in Wuhan, China: a single-center descriptive study. Chinese
Journal of Digestion, pp.151-156.
Cholewińska, P., Czyż, K., Nowakowski, P. and Wyrostek, A., 2020. The microbiome of the
digestive system of ruminants–a review. Animal health research reviews, 21(1), pp.3-14.
Lobo-da-Cunha, A., 2019. Structure and function of the digestive system in molluscs. Cell and
tissue research, 377(3), pp.475-503.
Tao and et. al., 2020. Exosomes-coated bcl-2 siRNA inhibits the growth of digestive system
tumors both in vitro and in vivo. International Journal of Biological Macromolecules, 161,
pp.470-480.
Khoa and et. al., 2021. An integrative description of the digestive system morphology and
function of Japanese flounder (Paralichthys olivaceus) during early ontogenetic
development. Aquaculture, 531, p.735855.
Zumbach, J., von Kotzebue, L. and Pirklbauer, C., 2022. Does Augmented Reality Also
Augment Knowledge Acquisition? Augmented Reality Compared to Reading in Learning
About the Human Digestive System?. Journal of educational computing research,
p.07356331211062945.
Lynch, R. and Buckin, V., 2022. Ultrasonic analysis of effects of varying temperature, pH, and
proteolytic enzymes on hydrolysis of lactose by neutral lactase formulations in infant milk
and in the infant digestive system. Food Research International, 157, p.111004.
Niehaus, A.J. and Mora, D.P., 2022. Digestive System and Abdomen. Medicine and Surgery of
Camelids, pp.336-390.
Online:
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