Human Alimentary Canal Function

This assignment delves into the intricate workings of the human alimentary canal. It explores each component's role in the digestive process, from ingestion to egestion. The document elucidates the steps of digestion – ingestion, digestion, absorption, assimilation, and egestion – providing a comprehensive understanding of how nutrients are extracted and utilized by the body.

DIGESTIVE SYSTEM

Table of Contents
INTRODUCTION...........................................................................................................................3
MAIN BODY...................................................................................................................................3
Definition and functions of alimentary canal organs.............................................................3
1. Description on the ingestion of the pasta:..........................................................................5
2. Difference between mechanical and chemical digestion of the pasta................................5
3. Description on the absorption and assimilation of pasta:...................................................6
4. How and why egestion is carried out:................................................................................6
CONCLUSION................................................................................................................................6
REFERENCES................................................................................................................................7

INTRODUCTION
Alimentary canal of a human body is a tubular passage that extends from mouth to the
anus. It creates a tract in which food is passed and digested (Purchon, 2013).This whole
procedures is segregated into different processes. In the present report, structure of alimentary
canal will be discussed along with their relation with the functional of alimentary canal. Also,
principles of different digestive processes namely ingestion, digestion, absorption, digestion and
egestion will be analysed along with their contribution to the efficient system.
MAIN BODY
Definition and functions of alimentary canal organs
Alimentary canal is regarded as the digestive tract through which food is entered in
human body and solid wastes are expelled out. It is long hollow tube running from mouth to
anus. It constitutes integration of several organs and build a complete digestive system. It will
amaze that the average length of this tube is 5 to 6 meters. In order to make itself fit in the human
body, this tract is coiled inside the abdomen (Rehfeld, Nylander and Karnov, 2017). The
function of alimentary canal is to accept entry of food in human body and them to expel it out. In
order to attain this, various organs that are used are as follows: mouth, stomach, the small
intestine, oesophagus, large intestine, anus, pancreas, rectum, etc. Also, there are some other
organs which are used in supportive actions to function alimentary canal. All these can be seen
by the following diagram:

This system can be further segregated into two sections namely, upper gastrointestinal tract
consisting oesophagus, stomach and duodenum (first section of small intestine) and lower
gastrointestinal tract constituting (most of the small intestine and whole large intestine).
Description of some major organs that completes the procedure of alimentary canal is as follows:
 Oesophagus- It is a long muscular tube that carries food from mouth to stomach. It
originates from the throat cavity known as pharynx. At the time when food is swallowed,
the bolus moves down the oesophagus of human body and with the muscle movement it
reaches the stomach itself (Ammar, Hall and Shatters, 2017).
Illustration 1: Alimentary canal
Source: (Agarwal, 2017)

 Stomach: This is a significant part of the upper gastrointestinal tract which is a hollow
bag like in structure. In this, the bolus gets merged with the major digestive acids for the
further breakdown. The material here is converted into chyme. It is further send to the
small intestine where the nutrients are absorbed.
 The small intestine: It is 20 feet long digestive tube having tiny interior projections
named as villi. These are present to boost the surface area for better absorption of
nutrients. There are three parts of it, duodenum, jejunum, ileum. The chyme when entered
into different segment of small intestine, pancreatic juices and biles are used to break
apart fats and proteins.
 The large intestine: After the absorption of nutrients the food waste reaches the large
intestine. It is also known as colon which compacts the waste material, removes extra
water and develops faeces (Zhang and et. al., 2013).
 Rectum: It is the final section of the large intestine that terminates to the anus. Similar to
the colon, here water is absorbed and indigestible food particles are decomposed with the
help of anaerobic bacteria.
 Anus: It is the 2 inch long canal which is opening of the alimentary canal which plays the
role of expelling the solid waste out of the body.
Thus, in this way the structure of alimentary canal is related to the major function it
performs. The basic stages of the digestive process or structure of alimentary canal can be well
explained by taking an example. Taken for instance, the digestion process of pasta involves the
following:
1. Description on the ingestion of the pasta:
Ingestion is the very first step of the digestive process in which the pasta will be
consumed by the human body from different sources in the environment. This process includes
all those activities in which the pasta is in mouth or buccal cavity. These processes are chewing,
grinding with the teeth, lubrication effect of saliva, chemical effect of salivary glands,
swallowing of pasta. (Zheng and et. al., 2014).
2. Difference between mechanical and chemical digestion of the pasta.
Digestion is the most important process of the overall cycle. In this, the consumed pasta
will be break down into soluble substances with the help of digestive juices and enzymes. There
are mainly two type of processes that are performed in digestion, mechanical and chemical.

Many organs plays a role in the breakdown of pasta. For instance: Mechanical actions includes
teeth to breakdown food whereas chemical digestion involves creation of bile by the liver that
acts as an emulsifier. The major role is played by this bile which is initially stored in the gall
bladder at the time of fasting stages and later it is send to the small intestine (Chemical process).
In order to break the complex proteins and fats present in the pasta, pancreatic juices are excreted
into digestive system (mechanical plus chemical process).
3. Description on the absorption and assimilation of pasta:
Absorption is the process in which the soluble pasta particles are absorbed by the blood
stream. This process occurs in the small intestine. It is the organ in which nutrient directly enters
the blood stream. This nutrients are passed directly to stream for their distribution in the rest of
the body. Whereas, assimilation is the process in which the pasta particles carried by the blood
stream are absorbed by the cells of body. These chemicals are liquid refreshments such as milk
drinks, fruit juices, etc. This step takes place after the digestion and absorption of food.
4. How and why egestion is carried out:
Egestion is the last step of the digestive process in which the undigested food is thrown
out of the body. The undigested matter cannot be stored in the human body and thus, it is egested
out. It is the excretion of metabolic waste products from anus via rectum (Zhang and et. al.,
2013).
Thus, in this way all these digestive processes contributes in the effective functioning of
the alimentary canal for digestion of food.
CONCLUSION
From the present report, it can be said that all the components of alimentary canal plays a
crucial role in the digestion process. It has been studied that the complete process is completed
with the involvement of various body organs. All these elements are assigned with a certain task
to perform for accomplishing the function of alimentary canal.

REFERENCES
Books and Journals
Purchon, R. D., 2013. The biology of the Mollusca. Elsevier.
Rehfeld, A., Nylander, M. and Karnov, K., 2017. The Digestive System I: The Alimentary Canal.
In Compendium of Histology (pp. 433-473). Springer, Cham.
Ammar, E. D., Hall, D. G. and Shatters, R. G., 2017. Ultrastructure of the salivary glands,
alimentary canal and bacteria-like organisms in the Asian citrus psyllid, vector of citrus
huanglongbing disease bacteria. Journal of Microscopy and Ultrastructure. 5(1). pp.9-
20.
Zhang, M., and et. al., 2013. Identifying potential RNAi targets in grain aphid (Sitobion avenae
F.) based on transcriptome profiling of its alimentary canal after feeding on wheat
plants. BMC genomics.14(1). pp.560.
Zheng, X., and et. al., 2014. New specimens of Yanornis indicate a piscivorous diet and modern
alimentary canal. PLoS One. 9(4). pp.e95036.
Online
Agarwal. N., 2017. What are the different parts of Alimentary canal in human beings? [Online].
Available through: <http://www.preservearticles.com/201101042477/alimentary-canal-in-
human-beings.html>