Essential of Health and Disease

The Normal Functioning of Digestive System

The digestive system is a physiological process that takes place in the human body. It is a process that breaks down food that is ingested. Once the food is broken down, it is ready for absorption into the body for use. This essay, therefore, gives a categorical process of digestion. As such, it explains what exactly takes place in each anatomical components of the system. Basically, digestion process is triggered when a person smells or sees food. Therefore, as one prepares the meal, the smell or sight senses transmit this to the brain causing the brain send impulses to salivary glands. This causes the glands release saliva in preparation for digestion action. Apart from that, the stomach releases pepsin and hydrochloric acid which gear up to act on the food. Once the food is ingested, the process of digestion begins.

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The Mouth and Salivary Glands

The mouth is exactly superior to the esophagus. It is made of epithelial lining with soft tissue muscles. It should be noted that not all meals begin their digestion process in the mouth. For instance, digestion of proteins begins in the stomach while starchy food has its digestion initiated in the mouth. However, the mechanical process of breaking down meals acts on all hard meals in the mouth. In the mouth, presence of saliva plays some roles. Saliva moistens the food making it easier to swallow. Apart from that, it contains mucus which further reduces friction making the swallowing process simpler. There are three types of salivary glands. They are the submandibular, parodit and sublingual glands responsible for producing saliva which is essential for the initial digestion process. They are located posterior to the tongue. On a normal person, the four salivary glands do produce approximately 1.5 liters of saliva in a day. Once the food has been acted upon by teeth and mixed with saliva, a soft and moist mass known as bolus is formed. This is ready for swallowing.

The Movement of Bolus in the Esophagus

This is the pipe through which food passes to reach the stomach. It is inferior to the mouth. The esophagus is made of epithelium type known as squamous non-keratinizing. In the esophagus, a process known as peristalsis takes place. It facilitates movement of bolus towards the stomach. Peristalsis process occurs as a result of synchronized movement of waves along the esophagus muscles. The ability of the muscles to contract and relax facilitates the process of movement since the two processes push bolus down the esophagus. During swallowing, the muscles behind the bolus do contract while those ahead of the food relax. In the process, bolus moves with no resistance. As bolus approaches the lower end of the esophagus, pressure from it causes the lower esophageal sphincter to relax; ushering in bolus to the stomach. One major adaptation of the esophagus is presence of mucus lining which provides adequate lubrication that helps propel bolus.

The Digestion Process in the Stomach

It is in the stomach where much digestion activity takes place. The stomach is located in the left hypochondriac, umbilical, and epigastric, parts of the abdomen. It has got four major coats that constitute its structure: They include areolar, serous, mucous and muscular. Apart from these, the stomach has got vessels and nerves. The stomach lining has got numerous glands that release hydrochloric acids, gastric juice and peptinogen enzymes. In the presence of hydrochloric acid, peptinogen turns into pepsin which acts upon the proteins within bolus. Note that it is in the stomach where digestion of proteins begins due to presence of pepsin enzyme that converts proteins into amino acids. The absence of pepsin enzyme in the mouth explains why proteins do not begin their digestion process in the mouth. The stomach has got strong muscles that further break down the food into small particles. This process involves churning and mixing of the food. Once the food is mixed and acted upon by stomach enzymes, it turns into a soft creamy fluid known as chyme. The activities of digestion in the stomach take place for a period of three to four hours.

The ready chyme is acted upon by waves resulting from the contraction of stomach muscles. As a result, chyme is pushed to the initial section of the small intestine via the pyloric valve. This section is known as duodenum. The pyloric valve regulates the amount of chyme leaving the stomach. Normally, 4 cubic centimeters of chyme is released at a time. The rest is left in the stomach for further mixing.

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Digestion in the Pancreas, Liver and Gall Bladder

The pancreas, liver and gallbladder are essential anatomical components that facilitate the digestion process of chyme in the duodenum.


The pancreas has got a hockey stick shape and it is found in the abdominalpelvic cavity.It releases a number of enzymes that act upon chyme. Example of pancreatic enzymes are the pancreatic amylase which breaks down starch and glycogen; trypisn enzyme which breaks down amino acids into absorbable substances; steapsin enzyme which breaks down fats into fatty acids and glycerol; and nucleases which breaks down numerous nucleic acids such as RNAase and DNAase. In essence, the pancreatic juice has got lots of components which serve to break down carbohydrates, proteins and fats. Apart from that, the pancreas releases glucagon and insulin which regulate sugar level in the bloodstream.

Gall Bladder

The gallbladder is found in the abdominalpelvic cavity. This body part is responsible for storing and producing bile. When fatty food gets into the duodenum, the gall bladder contracts to squeeze out bile which is released into the duodenum through the bile duct. The role of bile is to facilitate digestion and absorption of fatty soluble vitamins and fats while in the small intestine. More so, it is essential for elimination of waste products such as bilirubin.

The Liver

The liver has got more than five hundred functions in the human body. However, its role in digestion involves further production of bile which is necessary as explained above. Apart from that, the liver helps in storage of nutrients, filtering of processed food; and processing digested food. The liver is found in the abdominalpelvic cavity.

The Small Intestines

The small intestines are located in the left lower quadrant (LLQ). Simple epithelial tissues cover the mucosa of the small intestine. The mucosa is made up of wrinkles and folds to increase surface area for absorption of nutrients. Having been acted upon by various enzymes produced in the duodenum, the food moves to the lower part of the small intestine known as jejunum. In this region, further mixing and breakdown of chyme takes place. At this point, it is broken down into small molecules that can be absorbed. As this process occurs, the molecules are further moved down within the small intestine to a region known as ileum. This is a long narrow duct in which much of the absorption process occurs. By the time the food reaches the tail end of the ileum, much of nutrients shall have been absorbed. The remnants include: electrolytes like chloride and sodium; excessive water; dead cells and plant fiber; among other wastes.

The Villi

One major anatomy component that facilitates absorption in the ileum are the villi. These are small projections that resemble fingers. They are located on the epithelial lining of the small intestines. The approximate size of a single villus is 1.5 millimeters. The villi have got microvilli which are tiny projections. This is an adaption since their small sizes increase the surface area for absorption of digested food. The villi and microvilli have got a semi permeable membrane that allows absorption through diffusion process. Once absorbed, nutrients get into the bloodstream for distribution to various body organs. The direct connection of villi to the blood vessels facilitates this process. Basically, the lipoproteins containing triglycerides, cholesterol are absorbed by the villus lacteals (lymph capillaries) while amino acids and simple sugars are absorbed by the villi capillaries.

The Large Intestine

This is also known as the colon and it is located at the caudal region of the human body. It is at this point where water is absorbed from the wastes emanating from the ileum. As a result, a hard substance known as stool is formed. Muscles along the colon push the stool down to the rectum for elimination through the anus.


The digestive system is one of the major processes that take place in the human body. It involves complicated procedures through which food is broken down to facilitate absorption for use in various body physiological processes. That underscores the significance of this process as far as survival of the human being is concerned. With these complex processes, the body must be in good health condition for the processes to occur effectively. Apart from that, every individual must consume meals that shall not cause problems during digestion. This can be achieved by taking a balanced diet as well as drinking adequate water. Needless to mention, over-eating should be avoided since, just like in any other processing machine, excessive supply of food disrupts the normal functioning of the digestive system.

Crohns Disease

Crohns disease is one of the most common diseases that affect the human body. It is also known as ileitis or enteritis. It is an ailment that is quite disturbing due to its appalling effects to an infected person. One notable thing about this disease is that it affects the digestive system in most cases. There is no specific place affected within the digestive tract. Basically, the disease may infect any part ranging from the mouth all the way to the rectum. Nevertheless, it has been discovered that this disease mainly affects the ileum. There is no known cause of this ailment. Despite that, its effects are obvious since they are extremely clear to detect. Among the symptoms of Crohns disease is the inflammation of the digestive tract. The inflammation occurs in patches depending on the area infected. It is a disease that can lead to short term and long term complications if not detected and cured. It is on record that this ailment cannot be prevented. However, understanding its mode of action to the physiology of the body offers patients and health experts a chance to find solutions as far as its management is concerned.

Given that this ailment affects the digestive tract, it is definite that it affects the digestion process as well as other physiological processes in the body. For instance, a patient suffering from severe Crohns disease may experience inflammation along the digestion tract. This is a painful experience that makes it difficult to swallow food. If the infection is in the mouth, for instance, chewing of food may be difficult. As a result, mechanical breakdown of food may be inhibited if not partially done. Thus, proper mixing of the food in the mouth does not occur. The bolus which is incompletely broken down shall be pushed to the esophagus down to the stomach. The presence of hard food in the stomach delays the digestion process leading to further complications such as constipation.

Swelling of the intestines due to Crohns disease is equally dangerous. As the intestines walls swell, the patient experiences excruciating pain and cramps. Normally, swollen walls of the intestines do not absorb much water and nutrients. As a result, the digestion process is tampered with leading to regular release of nutrient molecules and water into the rectum. This is usually accompanied by diarrhea. Basically, diarrhea is caused when the colon fails to absorb water from the stool. Thus, all the water is directed to the rectum which is later eliminated through the anus. This means a patient who experiences this process may end up losing excessive water and sodium ions. It is at such a stage that more homeostasis complications set in.

If the Crohns disease is not controlled, the ileum shall experience production of scar tissues along its walls. Scar tissues emanate from long term chronic inflammation. Once this tissue builds up in the intestine, a stricture is formed. The stricture refers to a narrow passage way which slows down movement of digestive materials along the intestines. This leads to slow movement of food along the tract causing cramps and or pain.

As far as homeostasis is concerned, it is the digestive system that regulates this process. This is ascribed to the fact that most nutrients that serve the physiological processes of the body are the product of digestion. In that light, any form of inhibition to the digestion system affects all physiological processes of the body. Thus, when Crohns disease affects the digestive tract, there shall be little or no digestion. That implies there shall be little or no absorption of nutrients in the body. Lack of nutrients in the body prevents physiological activities which regulate various body actions. Ultimately, the body shall weaken. In the long run, if no step to cure the disease is taken, death may occur.

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