Human Anatomy and Physiology of the Digestive System
The digestive tract plays a key role in the human organism, as it is responsible for the supply of energy for the organism to perform its basic functions. To be particular, this system of organs “takes in food, digests it to extract energy and nutrients, and expels the remaining waste” (1). As the digestive tract processes food and thus interacts directly with the environment, it can be subject to various infections.
For instance, viral gastroenteritis is the “inflammation of the gastrointestinal tract, an illness of fever, diarrhoea and vomiting caused by an infectious virus, bacterium or parasite” that affects small and large intestines (2). A brief comparison of the etiology, pathogenesis and clinical manifestation of viral gastroenteritis to the normal anatomy and physiology reveals the peculiar features of this disease. To start with, this disease affects the normal functioning of such organs as the stomach and the intestines.
As for the physiology, the regular process of digestion consists in passing food along the tract with breaking down it into smaller elements, so that nutrients are absorbed to the bloodstream. Chemical fragmentation of large molecules into clusters of smaller ones occurs with the help of special ferments (enzymes) and bacteria. After the nutrients are absorbed the food remnants are passed to the large intestine and then exposed as excrements. Viral gastroenteritis disrupts the regular physiology of digestion.
The gastrointestinal tract is infected by one of such viruses as rotaviruses, adenoviruses, caliciviruses, astroviruses, Norwalk virus, and a group of Noroviruses (3). This causes inflammation of the surface layer of the digestive tract. The pathology of this disease presupposes that these viruses interfere in the normal bacteria environment, destroy the surface cells of the digestive tract and prevent normal absorption of water and sodium during digestion.
As a result, the digestion does not occur correctly and the organism does not receive the sufficient quantity of nutrients, as it happens in the regular case. Thus the symptom of the disease is weakness, while the children may seem lethargic (2). Besides as the water balance cannot be maintained, the patients may suffer from dehydration. Therefore, the sick people are advised to compensate the loss of fluid in the organism by drinking a lot.
In the healthy human body the digestion presupposes the absorption of the required water quantity, so that the regulation process takes place automatically. Viral gastroenteritis also affects the excretion processes. Among the chief symptoms of this disease are “poor feeding in infants, vomiting and fever, usually rapidly followed by diarrhoea” (2), as well as nausea. In a healthy digestive tract the food passes through with the help of peristalsis, until its remnants are disposed of as feces.
In viral gastroenteritis the rhythmic muscular contraction of the tract is disrupted, its surface is inflamed, so that the food is forced back from the digestive organs in the form of nausea or vomiting. In most cases viral gastroenteritis is considered to be a self-limiting disease that is treated easily and does not cause serious pathological consequences to the organism. However in order to restore the normal physiology, it is necessary to ensure rehydration of the patient, so that the swollen surface cells of the digestive tract are not affected.
It is also important to consider the role of the digestive tract as a part of the immune system (1). Mucilage contains antibodies that, along with the low level of pH in the stomach, kills microorganisms tht are harmful for the organism. The enzyme in saliva and bile also serve this defence function. Intestinal bacteria sustain the environment in the digestive tract unfavourable for the harmful bacteria.
Viral gastroenteritis causes dehydration, that is reduction in the quantity of saliva, as well as the disruption of the regular bacteria environment. This leads to the impairment of the immune system, which is usually supported by the digestive tract defence. Consequently, the children with gastroenteritis may “may be lethargic and have signs of dehydration, dry mucous membranes, tachycardia, reduced skin turgor, sunken fontanelles and sunken eye balls, poor perfusion and ultimately shock” (2).
To sum up, viral gastroenteritis is an infection that affects the normal physiology of the digestive tract and causes disruption of digestive and excretion processes and dehydration. However, in most cases the regular functioning of the gastrointestinal tract can be restored without long-term consequences for the organism.
Bibliography 1. “Gastrointestinal tract”. Retrieved on February 14, 2006 from Encyclopedia Wikipedia on http://en.wikipedia.org/wiki/Digestive_systemSample Essay of StudyFaq.com