Digestive System: Overview, Structure, Function, and Constipation

Overview of the digestive system
Digestive system is defined as the group of organs working together in
order to convert food into energy and other basic nutrients which are important
for the body (Rizzo 2015). The overall interplay of the organs in the digestive
system occurs in the alimentary canal (Rizzo 2015).
Structure of digestive system
The digestive system is the largest system in the body and all the organs and
the glands which are the part of the digestive system constitute the alimentary
alimentary canal.
The first component of digestive system is mouth, the point where the
digestion starts. Mouth is popularly known as buccal or oral cavity. The salivary
glands present in the mouth initiates digestion. There are three sets of salivary
glands in the mouth. The salivary glands are commonly known as accessory
organs the produce watery secretion known as saliva that moistens the food
particles and initiates digestion (carbohydrate).
Teeth: It is the second component of digestive system which breaks the
food into small ingestible component and thereby helping to sallow. there are
32 teeth in human body.
Tongue: Tongue located within the buccal cavity is another component of
the digestive system which helps to detect taste.
Pharynx: The buccal cavity is followed by pharynx or throat, a funnel
shape tube which is connected with the posterior end of the mouth. It passes the
food to oesophagus through epiglottis and air to larynx.
Oesophagus: It connects pharynx to the upper gastrointestinal tract
(stomach) and carriers chewed food along its length.
Stomach: It is the main component of the digestive system or the
alimentary canal. It is a sack like structure located on the left hand side of the
abdominal cavity, inferior to diaphragm. It helps in storage of food for proper
digestion. Stomach also contains digestive juices and secretes hydrochloric acid
which in turn promotes the digestion of food.
Small intestine: Stomach is followed via small intestine, a long tube which
is 10 feet long and 1 inch in diameter. It is the lower part of the gastrointestinal
tract. Small intestine has three parts, duodenum, jejunum and ileum. The small
intestine especially the jejunum is folded into finger like projection known as
villi which promotes absorption of food.
Large intestine: Small intestine is followed by large intestine. The large
intestine has six parts starting from cecum, ascending colon, transverse colon,
descending colon, sigmoid colon and rectum.
(Rizzo 2015)
Secretory organs of digestive system
Liver and gall bladder: The main digestion is conducted by the digestive
juices secreted by the liver and is located to right side of the stomach. Beside
liver there is gall bladder, small pear-shaped organ which secretes bile to aid
digestion.
Pancreas: The digestive gland located posterior side of the stomach and
secretes and also helps to transport digestive juices into small intestine in order
to complete chemical digestion of foods.
Relation between the digestive system and cardiovascular system
• The digestive system of the body intakes solid food particles and breaks it down into its constituents nutrients
and this nutrients acts as the source of energy.
• The circulatory system pumps blood to different parts of the body and through blood, the energy reaches to
different parts of the body.
• Example, the when the body needs energy, it generates hunger. In response to hunger, individual consumes
food. The food is broken down into glucose and it absorbed into the blood stream through the finger like
projections from the small intestine, villi. Once the glucose gets transported into the blood it is broke down into
ATP and the circulatory system transport the energy to the different parts of the body.
• Thus it can be said that proper co-ordination between the circulatory and the digestive system helps in proper
absorption of the nutrients from the alimentary canal and subsequent transport of nutrients throughout the body
(Gordan, Gwathmey and Xie 2015).
Effect of linkage of cardiovascular system and digestive system in pregnant women
• The cardiovascular system also assists in performing digestion in pregnant women
• Normal blood pressure promotes normal peristalsis movement
• Change in the flow of the blood hampers the process of digestion and thereby creating abdominal discomfort
among patient
• Problem in digestion due to high blood pressure creates constipation and further increasing discomfort
• Lack of proper co-ordination among the circulatory system and the digestive system creates lack of proper
transport of nutrients and ATP in different parts of the body and thereby creating nausea.
(Gordan, Gwathmey and Xie 2015).
Student Names and ID
Understanding constipation
• Constipation is defined as slow movement of faeces that occurs through large intestine. It in often
associated with the movement of large quantities of hard and dry faeces through descending colon
that accumulates due to over-absorption of fluid.
• Varies pathological defects of the large intestine also leads to the generation of constipation like
tumours or ulcers which constrict the diameter of the intestine causing constipation.
• Infants are frequently constipated however, part of their training during early years of life helps to
prevent constipation.
• Clinical experience shows that if an individual restricts defecation to occur when the defecation
reflexes are generated then he or she might become the victim of constipation.
• Overuse of laxative also leads to the generation of constipation as it hampers the natural bowel
movements or the peristalsis movement
• Constipation can also result from spasm in the sigmoid colon
(Bae 2014)
Recommendation to overcome constipation
Establishment of the regular bowel movement habits early during the life like defecating in the morning
after bed or after the breakfast helps to reduce the chances of the development of constipation. This is
because; at this time gastrocolic and duodenocolic reflexes are high and cause mass movements in the
large intestine. Practising this habit early in life is important because developing constipation in later
stages of life, apart from abnormal pathology is much less likely.
Constipation during pregnancy
Anxiety, minimal physical exercise, change in the hormonal secretion, consumption of iron are
the main reason behind the increased chances of constipation among the pregnant women (Stukan et al.
2013). This is because all these changes which occur during pregnancy relaxes the smooth muscles of the
intestine and thereby increasing then chance of constipation.
Overcoming constipation during pregnancy
• In order to prevent constipation during pregnancy, few things that must be taken into consideration
include
• Consumption of high fibre diet: 25 to 30 grams intake of dietary fibre from vegetables, fruits, whole
grains and bran
• Consumption of adequate fluid: Drinking plenty of fluid like water, fruit juice along with the
combination of high fibre diet helps in the proper elimination of waste from the body
• High fibre diet along with the consumption of water increases the water content of stool and thereby
making the waste soft and large. This in turn promotes the easy movement of the stools through the
intestine. Moreover, the insoluble fibre adds bulk to the faecal material which increases the passage of
stool through colon (Haider and Bhutta 2017).
• Routine exercise: Mild to moderate physical exercise for 20 to 30 minutes per day helps to reduce
constipation via regularizing the bowel movements
(Hashem Dabaghian et al. 2015)
Function of digestive system
The main function of the digestive system and can highlighted as follows:
• Ingestion of food,
• Secretion of the digestive enzymes, biles and fluids
• Mixing and movements of food and wastes through the body (small intestine
and large intestine)
• Breakdown and digestion of food into smaller pieces
• Absorption of nutrients
• Excretion of the undigested food
Ingestion
It is the first function of digestive system and is mainly carried out by the buccal
cavity.
Secretion
During the course of the day, the alimentary canal or the digestive system of
the human body secretes digestive fluids and juices, which includes saliva, mucus,
digestive enzymes, biles and hydrochloric acid. All these secretion aids in digestion
via acting as a lubricant or catalyst for the breakdown of food particles into smaller
parts.
Mixing and movement
There are three principal processes behind mixing and movements and these
include
• Swallowing: Process used for transition of food from mouth through pharynx to
the stomach
• Peristalsis: The muscular wave produced by the gastro-intestinal tract for the
movement of the partially digested food through the stomach and then through
the intestine.
• Segmentation: It occurs mainly in small intestine. During this process,
digested and undigested food gets separated leading to the absorption of the
digested food nutrients into the blood stream and passage of the undigested
food into the colon.
Digestion
It is the main function of the digestive system and is aided by the digestive
juices and the enzymes, which promotes the breakdown of large food particles into
smaller digestive parts followed by breakdown of the small food particles into their
constituents nutrients followed by the generation of energy in the form of ATP.
Absorption
Mainly occurs in the small intestine and in the stomach. Large intestine is also
involved in absorption of water and vitamins from the food into the body fluid
Excretion
It is the Last and the final function of the digestive system which is popularly
known as defecation. It means removal of indigestible substances from the body
and occurs through colon followed by rectum.
(Svihus 2014)
Clinical Scenario: Digestive System
Figure: Different parts of the alimentary canal
(Source: Hall 2015)
Figure: Anatomy and Function of digestive system
(Source: Svihus 2014)
Figure: Obstruction in different parts of the gastrointestinal tract
(Source: Hall 2015)
References
Bae, S.H., 2014. Diets for constipation. Pediatric gastroenterology, hepatology & nutrition, 17(4), pp.203-208.
Gordan, R., Gwathmey, J.K. and Xie, L.H., 2015. Autonomic and endocrine control of cardiovascular function. World journal of cardiology, 7(4), p.204.
Haider, B.A. and Bhutta, Z.A., 2017. Multiple‐micronutrient supplementation for women during pregnancy. The Cochrane Library.
Hashem Dabaghian, F., Taghavi Shirazi, M., Amini Behbahani, F. and Shojaee, A., 2015. Interventions of Iranian traditional medicine for constipation during pregnancy. Journal of Medicinal
Plants, 1(53), pp.58-68.
Rizzo, D.C., 2015. Fundamentals of anatomy and physiology. Cengage Learning.
Stukan, M., Kruszewski, J.W., Dudziak, M., Kopiejć, A. and Preis, K., 2013. Intestinal obstruction during pregnancy. Ginekologia polska, 84(2), pp.137-141.
Svihus, B., 2014. Function of the digestive system. Journal of Applied Poultry Research, 23(2), pp.306-314.
Source:
(Haider and
Bhutta
2017)
Figure: Constipation
and pregnancy