Egestion and Digestion

The human body’s life processes are amazing. They are not only self-contained, but they are also extremely intelligent, which makes them even more fascinating and lovely. Digestion is one of the most vital phases in ensuring our survival, which is why it is such an important aspect of our life. The waste product produced during digestion is collected in the form of feces, and the act of removing this waste from the body is known as egestion.

Not just humans, but other species that rely on food for survival have systems for removing waste from their bodies. We all eat food, from minute organisms like amoeba to huge animals like humans, and we all have a technique of getting rid of it.

Digestion and Egestion

Digestion: Digestion is the mechanical and enzymatic breakdown of food into molecules that may be absorbed into the circulation. Fats, carbs, and proteins are three macronutrients that must be digested before they can be absorbed. These macronutrients are broken down into molecules that may pass through the intestinal epithelium and reach the bloodstream to be used by the body during digestion. Mechanical digestion comprises physically disintegrating dietary items into tiny pieces to speed up chemical digestion. Digestive enzymes further degrade the molecular structure of ingested substances, allowing them to be absorbed into the circulation. 

Digestive system: The gastrointestinal tract, as well as the digestive organs that support it, make up the human digestive system (the tongue, salivary glands, pancreas, liver, and gallbladder). During digestion, food is reduced down into tiny pieces until it can be absorbed and assimilated into the body. The cephalic phase, the stomach phase, and the intestine phase are the three phases of digestion.

The initial step of digestion, known as the cephalic phase, begins with stomach gland secretions in reaction to the sight and smell of food. In the mouth, food is mechanically broken down by chewing and chemically broken down by digestive enzymes. The digesting enzymes amylase and lingual lipase are released by the salivary and serous glands of the tongue, and are found in saliva. Chewing is the first step in the physiological digestion process, in which the foodstuff is mixed with saliva. This creates a bolus, which is then ingested and sent down the esophagus into the stomach.

The gastric phase begins the second stage of digestion in the stomach. The meal is further broken down in the duodenum, which is the first section of the small intestine, by interacting with stomach acid.

The intestinal phase of the third stage begins in the duodenum, where partially digested food is combined with a variety of enzymes generated by the pancreas. Food is chewed by the mastication muscles, tongue, and teeth, as well as peristalsis and segmentation contractions, which help digestion. In order for digestion to continue, gastric acid and mucus must be produced.

Human digestion process: The length of the human gastrointestinal system is approximately 9 meters. Food digestion physiology differs from person to person and depends on a variety of factors such as the type of food consumed and the amount of the meal consumed, with the digestion process typically taking between 24 and 72 hours.

Saliva and its digestive enzymes start the digestion process in the mouth. By mechanical mastication, food is shaped into a bolus and ingested into the esophagus, from whence it reaches the stomach by peristalsis. Because hydrochloric acid and pepsin in gastric juice can disrupt the stomach’s walls, mucus and bicarbonates are synthesized to safeguard them. More enzymes are released in the stomach, breaking down the meal even more, and this is paired with the stomach’s churning movement. Proteins are mostly digested in the stomach. As a thick semi-liquid chyme, partly digested food reaches the duodenum. The majority of digestion takes place in the small intestine, which is aided by bile, pancreatic juice, and intestinal juice secretions. The intestinal walls are lined with villi, and their epithelial cells are coated with many microvilli to increase the surface area of the gut and promote nutritional absorption. Bile aids in the emulsification of lipids and also acts as a lipase activator. Food passes more slowly through the large intestine, allowing the gut flora to ferment it. Water is absorbed here, and waste is retained as faeces, which is afterwards defecated through the anal canal and anus.

Egestion: Egestion is the process of excreting useless or undigested material from a cell, as in single-celled organisms, or from a multicellular animal’s digestive system.

The first section of the big intestine is known as the colon. It absorbs the majority of the remaining liquid. This results in faeces, a semi-solid waste product. The rectum, the final section of the large intestine, is where the faeces are kept. When these faeces flow out of the body through the anus, it is called egestion.

Importance of egestion: Egestion is an important activity in humans and animals because it allows undigested food to exit the system. If bowel movement is delayed for an extended length of time, it might result in a megacolon, which can lead to bowel rupture.

Egestion in Digestive System

The egestion process in humans and other higher animals involves waves of muscular contractions of the colonic walls, which move the faeces towards the rectum. The rectum ampulla is used to temporarily store faeces. The rectal walls stretch when fecal waste collects. The stretch receptors in the rectal walls are triggered, the rectal muscles contract reflexively, the internal anal sphincter relaxes, and the skeletal muscle of the external anal sphincter contracts. 

As a result, there is a strong need to eliminate the faeces. When not acted upon, reverse peristalsis occurs, in which the material returns to the colon for additional water absorption and temporary storage until the next wave of transverse and descending colon muscle contractions. Valsalva maneuver is carried out during defecation. Air is ejected against a blocked airway in this manner. As the thoracic diaphragm is pushed down, the lungs are unable to breathe. The digestive tract is put under strain as a result. 

Difference between Egestion and Excretion

You can easily distinguish between the terms if you pay attention to them. Both terms allude to the physiological process of removing waste items from the body. Both phrases refer to the removal of undigested or waste products from a cell or a body in their literal sense. Regardless, there is a subtle distinction between excretion and egestion.

• Egestion is the removal of undigested food particles from a multicellular organism or a complicated anatomical system. Excretion, on the other hand, is the process of a multicellular organism’s cells removing waste materials.
• Undigested food particles make up the content lost at the conclusion of an organism’s digestive tract. These undigested particles are the byproducts of a lengthy digesting process that ends in egestion. The by-products of cellular metabolism are excreted by perspiration, urine, and other means. Excretion may also be seen in plants shedding leaves and getting rid of metabolic by-products. The content removed via egestion and excretion differs.
• The anus is where food is eliminated. The skin, kidneys, and nose are all sources of excretion.
• Egestion can be observed in animals with a mouth and an anus. Plants and animals, on the other hand, excrete their waste.

Conclusion

Digestion is the process of breaking down and chemically transforming food so that it may be absorbed by cells. Food is chewed in the mouth, combined with saliva, which begins to break down carbohydrates, and kneaded into a ball by the tongue for swallowing.