Digestion is one of the most critical processes that occur in the human body. Through this process, food is broken down into simpler components that can be absorbed into the body. There are various organs that constitute the digestive system. Each of these organs serves important roles. The different organs collaborate to ensure that once ingested, food undergoes proper breaking down. As is the case with other systems, the digestive system is susceptible to a number of diseases. Understanding these diseases is the first step in ensuring that ill health does not impair the functioning of the system.
Components of the digestive system
The salivary glands, pharynx, esophagus and the stomach are some of the main organs in the digestive system (Rogers, 2010). Other organs that make up this system include the small and large intestines and the rectum. The primary function of the salivary glands is to release the saliva that aids the digestion of food. The saliva contains salivary amylase which plays a crucial role in the breaking down of carbohydrates. The saliva also serves as a lubricant which facilitates the passage of food (Rogers, 2010). The main function that the pharynx serves is that it allows for the passage of the food to the stomach. The esophagus and stomach perform roles that are particularly important. The esophagus serves a function that is somewhat similar to that of the pharynx. It is the conduit through which food makes its way to the stomach. Breaking down food partially is among the roles that the stomach performs (Rogers, 2010). As it churns, the stomach participates in the digestion of food. The stomach is particularly heavily involved in the digestion of proteins. The breaking down of foods in this group is initiated in the stomach. The digestion of the proteins is possible because the stomach releases enzymes such as pepsin which allows for the digestion of proteins. The storage of food is another vital function that the stomach serves (Rogers, 2010). Producing chyme and eliminating harmful bacteria are other roles of the stomach. The ultimate purpose of the digestive process is the absorption of food into the body. The small intestines allow for the attainment of this purpose. Their key role is to absorb nutrients from the foods that one has consumed (Rogers, 2010). The large intestines are also involved in some form of absorption. They absorb water and create fecal matter.
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The organs discussed above are not the only components of the digestive system. Glands and hormones also make up this system. The salivary glands whose functions have been outlined above are among the glands that serve some functions in the digestive process. Apart from the salivary glands, the digestive system benefits from such other glands as the pancreas, the liver, the gastric glands and the intestinal glands (Rogers, 2010). The pancreas’ main role is to release enzymes (digestive juices) into the small intestines where further digestion takes place. As regards digestion, the liver serves various functions. One, it is involved in the processing of the nutrients that the small intestine absorb into the bloodstream (Ross, McMahon & Bernstein, 2016). Two, the liver secretes bile. This substance aids the digestion of fats in the small intestine. The secretion of gastric juice the mucus which protects the stomach are the chief roles of the gastric lands. The primary role of the intestinal glands is to neutralize the hydrochloric acid (Rogers, 2010). The mucus, digestive enzymes and hormones that are found here allow the intestinal glands to perform this function. These glands also aid the digestion of proteins.
Hormones are yet another component of the digestive system. Motilin, gastrin and secretin are the main hormones that fuel digestion (Reynolds, 2016). Motilin is involved in the metabolism of fat while gastrin sets the stage for the secretion of gastric acid. On the other hand, secretin’s main function is to control the acidity of the duodenum. The duodenum is responsible for the secretion of secretin. Tissues also make up the digestive system. Connective, epithelial, muscle and nervous tissues are all found in the digestive system. While the muscle tissue facilitates the movement of food down the gut, the nervous tissue ferries electrical impulses to the brain (Rogers, 2010). Connective tissue carries blood and nutrients. The major function of the epithelial tissue is housing such cells as goblet cells which are involved in the production of mucus. The following image shows the major parts of the human digestive system:
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Diseases of the digestive system
There are various diseases that affect the human digestive system. Some of these diseases are explored in the following section.
Gastroesophageal reflux disease (GERD)
Description and symptoms
GERD (acid reflex) is one of the most common diseases of the digestive system. This disease is chronic and occurs when the lining of the food pipe suffers irritation as a result of bile flowing into the food pipe (Choi, 2018). There are a number of symptoms that characterize this disease. Dry cough, bitter taste and heartburn are some of the symptoms. Individuals who suffer nausea and belching may also have developed this disease. Pain in the lower abdomen region may also be a sign that the disease has taken hold.
Causes
Various factors have been identified as among the possible causes of GERD. Most of these factors concern lifestyles. Some foods have been linked to this condition. These foods include chocolate, fatty foods and coffee. Beverages that contain alcohol are also a risk factor for GERD. Smoking cigarettes also exposes one to the risk of suffering GERD (Choi, 2018). There is some evidence that pregnancy and obesity are also to blame for the condition (Choi, 2018).
Treatment
While it is a serious disease, GERD is treatable. In fact, it is possible for individuals to administer self-care. Some of the measures that one ailing from the disease can institute include making changes to their diet and losing weight (Choi, 2018). These measures eliminate the risk factors such as obesity and poor dietary habits. The administration of medication is another approach to treating GERD (Choi, 2018). Some of the medications that tackle this disease are antacid and proton-pump inhibitor.
Gallstones (cholelithiasis)
Description and symptoms
Gallstones is yet another disease that affects millions across the world. It is important to note that this is not a disease per se. Hardstones are merely deposits in the gallbladder that are composed of digestive fluids (“Understanding Gallstones”, n.d). For most individuals, gallstones do not present any symptoms. However, there are a few who exhibit certain symptoms. Vomiting, nausea and indigestion are some of these symptoms (“Understanding Gallstones”, n.d). Other symptoms are discomfort and pain which varies in severity. Upon displaying these symptoms, individuals need to seek medical help as soon as possible. Failure to seek treatment could see an individual develop a number of complications. Jaundice and sepsis are among the complications that could result when gallstones are left untreated.
Causes
The scientific and medical communities are yet to identify with certainty the causes of gallstones. However, this has not kept them from developing theories. One theory posits that excessive amount of cholesterol in the bile is a possible cause (“Understanding Gallstones”, n.d). When one’s bile contains very high levels of bilirubin, they could also develop gallstones. These theories should be accepted with caution. There is also need for the scientific and academic professions to commit greater effort to establish the causes of gallstones.
Treatment
Various interventions are available for the treatment of gallstones. Self-care is among these interventions. Adopting a low-fat diet is among the interventions that individuals can apply without the involvement of a medical professional (Bateson, 2012). Taking medications that lower cholesterol levels is among the pharmacological approaches that are effective in treating gallstones. In extreme cases, surgery may be required (“Gallstones”, 2018). The surgery involves the removal of the gallbladder.
Celiac disease
Description and symptoms
In recent years, celiac disease has emerged as among the most daunting medical challenges. This disease occurs when the immune system responds aggressively to gluten (NIDDK, 2016). The result is that the lining of the small intestines becomes damaged and is therefore unable to absorb nutrients properly. Diarrhea and bloating are some of the characteristic features of celiac disease. Fatigue, osteoporosis and anemia are other symptoms that those with this disease display (NIDDK, 2016). It should be noted that many individuals ailing from celiac disease do not display any symptoms.
Causes
Genetics is the main culprit that has received blame for causing celiac disease (NIDDK, 2016). Individuals who carry particular genes face an elevated risk of developing the disease. Those with the disease can also pass it on to their children. For the most part, celiac disease remains a mystery. It is yet to be fully understood how this disease develops. With further research, the medical and scientific communities will inch closer to understanding what causes celiac disease.
Treatment
It is very unfortunate that there is no effective cure for celiac disease. This does not mean that those with the disease are at its mercy. Avoiding foods that contain gluten is recommended as an effective strategy to manage the disease (NIDDK, 2016). Since the immune system reacts to gluten, avoiding foods that contain gluten must be an effective strategy.
The following table provides the definitions of some of the most common terms that are related to the digestive system.
| Term | Definition |
| Stool culture | A processed used to detect bacteria that could cause such problems as diarrhea (“Digestive Diagnostic Procedures”, n.d). |
| Fecal occult blood test | Test employed to determine if there is blood in fecal matter (“Digestive Diagnostic Procedures”, n.d). |
| Defecography | Procedure involving the use of X-ray to determine how complete defection has been (“Digestive Diagnostic Procedures”, n.d). |
| Oropharyngeal motility study | An X-ray process where a liquid laden with barium is administered for the purpose of monitoring the swallowing process (“Digestive Diagnostic Procedures”, n.d). |
| Colonoscopy | Procedure for evaluating the large intestine. Focus is given to identify any abnormalities such as growths (“Digestive Diagnostic Procedures”, n.d). |
| Sigmoidoscopy | A diagnostic procedure that focuses on the large intestine (“Digestive Diagnostic Procedures”, n.d). |
| Esophageal manometry | A procedure that is used to measure how strong the muscles in the anus and rectum are (“Digestive Diagnostic Procedures”, n.d). |
| Capsule endoscopy | A diagnostic procedure used to assess the state of the small intestines (“Digestive Diagnostic Procedures”, n.d). |
| Amylase | Enzyme involved in the digestion of starch (Illades, 2010). |
| Bile | Fluid produced in the liver that is essential in the fat digestion (Illades, 2010). |
| Chyme | The food that has undergone partial digestion as it leaves the stomach and enters the small intestines (Illades, 2010). |
| Dysphagia | A situation characterized by challenges in swallowing (Illades, 2010). |
| Lactose intolerance | Difficulty that some people encounter in breaking down lactose contained in dairy products (Illades, 2010). |
| Malabsorption | The difficulty encountered in absorbing nutrients into the bloodstream (Illades, 2010). |
| Peristalsis | The movements of the muscles along the gut which push food down the gut (Illades, 2010). |
References
Bateson, M. C. (2012). Gallstone Disease and its Management. New York: Springer.
Choi, J. (2018). Everything you need to know about GERD. Retrieved March 7, 2018 from
https://www.medicalnewstoday.com/articles/14085.php
Digestive Diagnostic Procedures. (n.d). Retrieved March 7, 2018 from
https://www.hopkinsmedicine.org/healthlibrary/conditions/digestive_disorders/digestive_diagnostic_procedures_85,p00364
Gallstones. (2018). Retrieved March 7, 2018 from
https://www.nhs.uk/conditions/gallstones/treatment/
Illades, C. (2010). A Digestive Health Glossary. Retrieved March 7, 2018 from
https://www.everydayhealth.com/digestive-health/glossary-of-digestive-health-terms.aspx
National Institute of Diabetes and Digestive and Kidney Diseases. (2016). Symptoms &
Causes of Celiac Disease. Retrieve March 7, 2018 from
https://www.niddk.nih.gov/health-information/digestive-diseases/celiac-disease/symptoms-causes
Understanding Gallstones: Types, Pain and More. Retrieved March 7, 2018 from
https://www.healthline.com/health/gallstones
Reynolds, J. C. (2016). The Netter Collection of Medical Illustrations: Digestive System:
Part 1- The Upper Digestive Tract. Amsterdam: Elsevier Health Sciences.
Rogers, K. (2010). The Digestive System. New York City: The Rosen Publishing Group.
Ross, I. D., McMahon, K., & Bernstein, M. (2016). Nutrition. Jones & Bartlett Publishers.
1 Image retrieved from http://baldaivirtuves.info/human-body-anatomy-digestive-system/human-body-anatomy-digestive-system-introduction-to-human-digestive-system-anatomy-human-anatomy-physiology/
