Digestive System Physiology for Hepatitis Patients Part Three

The Motility in GI Tract

Digestive system

The digestive system secretes different fluids, summing up to 7 liters a day, in the whole process of digestion and absorption of the food nutrients. The fixtures responsible for emitting these fluids are the exocrine glands, which secrete water, ions, mucins, and other fluids that are essential for the digestive process. These glands or fluids are secreted via (a) the walls of intestine and stomach, (b) the gastrointestinal tract, or (c) the organs outside the intestines such as the pancreas and liver.

Hepatitis and Physiology: Secretion and Excretion

One of the fluids secreted through the digestive system process is the saliva. The saliva is the one responsible for demulsifying the chow as it enters the mouth. It contains salivary amylase which has digestive enzymes that begins the desolation of carbohydrates. The digestive system also secretes mucus which serves as a lubricant and a protective barrier inside the GI tract. The hydrochloric acid is the one that protects our body from repugnant bacteria by helping the digestive system in the carnage of microbes present in food that’s been consumed. It also aids the digestive system in the chemical digestion of the food. The different enzymes secreted through the process of digestion helps in curdling the large molecules such as protein, lipids and carbohydrates, into smaller bits of particles. The bile excreted by the liver is responsible in emulsifying large particles of lipids into smaller particles to make the digestive organ digest and absorb it easily.

The bile, however, is constituted of different substances given off by the liver.

Notwithstanding that fluids are aids for the digestion and absorption process, human waste, which is undigested matter eliminated by the intestinal tract, is also considered substances in the secretion process. The feces are mainly composed of bacteria present from the undigested materials such as cellulose – a plant cell membrane component that snubs to be absorbed.

Since the feces or undigested residues were never actually inside the body, but were composed from the exiting bacterial substances from the food product residue, the feces are considered to be eliminated, not excreted. Because the feces are not necessarily needed by the body, and must not actually be accumulated and be taken nor kept for long in the body, the human waste is being in a timely manner – a scheduling controlled by a specialized part of the brain.

The Motility Outlook: Hepatitis and Physiology

The gastrointestinal tract, approximately 15 feet long, is composed of a long tube with one hole for entering, which is the mouth, and another one hole for exiting, which is the anal canal. Hence, the food, as it enters the mouth, must continuously progress and keep prodding forward in through the gastrointestinal (GI) tract. The food must also reach its certain destinations for specific sites known for mixing, absorbing and digesting respectively.

There are three main courses for the mixing and moving of the food through the GI tract.

First is the swallowing. Swallowing is the process of making the food traverse through the mouth with the help of the tongue, in order to drive it through the pharynx or throat until it meets the esophagus. The food undergoes first in an oral phase of swallowing where the food is being moistened by the salivary produced by the salivary glands. The nutriments then will be masticated, or chewed, where they will be mechanically broken down to smaller shards through the action of the teeth. While in the process of mastication, the food becomes a bolus lubricated with enough saliva. The food won’t be swallowed and shuttled from the mouth to the pharynx if it is too dry or does not have enough lubrication of saliva. The bolus will then be pushed to the back of the tongue where a trough will be formed. This manger makes the tongue become elevated to the upper palate of the mouth. The end of the oral phase is when the food has already been prepared to be moved from the mouth to the pharynx.

Since hepatitis is often considered a digestive disease, the hepatitis patient should know that the next phase of swallowing will be the pharyngeal phase. In this phase, other activities such as breathing, chewing, vomiting, and coughing are concurrently inhibited. The nasopharynx locks firsts while the pharynx is being prepared to receive the bolus. As the bolus enters the pharynx, the auditory tube, which couples the nasopharynx to the middle ear, unwraps. However, this process of opening of the auditory tube does not contribute to the process of swallowing; but it consequently happens though. The oropharynx – the oral branch of the pharynx – and the laryngeal tube are kept close, while the bolus travels down towards the esophagus. Once the bolus gets to the esophageal stage, the current of peristalsis is protracted compared to the pace of this involuntary muscular movement happening from the pharynx. If the food has finally grasped the stomach, both the pharynx and the esophagus will cross into a relaxed state.

Hepatitis and Physiology: Closing Remarks

The next major process responsible for the motility of the swallowed food is peristalsis, an involuntary muscular undulation that continuously pushes down the food along the GI tract, starting from the pharynx until it reaches its exit point. Finally, the third main process for mixing and movement of food is the segmentation, which occurs in the small intestine. This refers to the process of the contraction of the small intestine to squeeze the foods being digested. This retrenchment is to enable the better absorption of the nutrients of the food, as it increases the contact of the chyme to the walls of the small intestine. The digestive system plays a very decisive role in the body - supplier of the nutrients for the total organism. Therefore, it’s worthy to understand the processes involved in the propulsion of food devoured. This also enables the one who has hepatitis to become aware and purchase healthy foods that enhance the digestive system.


Chapman HW, reviewer. Comparative physiology of the vertebrate digestive system. Can Vet J. 1997 Sep; 38(9): 576–577.

Karasov WH, Martínez del Rio C, Caviedes-Vidal E. Ecological physiology of diet and digestive systems. Annu Rev Physiol. 2011;73:69-93.

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