Which of the following is not a function of the digestive system?

Which of the following is not a function of the digestive system? A Function that Doesn’t Fit

The Digestive System: A Vital Part of the Human Body

The digestive system is an essential part of the human body, with the function of food digestion, providing the body with dietary nutrients for growth, energy and repair. By this process the waste products of which the body is not in need are also excreted, i.e. Without the digestive system, we would not be able to obtain the required energy and nutrients from the food that we eat, which is crucial for survival.

The digestive system operates under very serial, sequential process with a number of different organs and structures engaged in food breakdown, nutrient absorption, and waste ejection. Knowledge of the digestive system goes not only with the knowledge of what it is, but with the knowledge of what should be distinguished from the other systems in the body as conditions for overall health, such as the health of the respiratory system. Let's discuss in greater detail the digestive system, its functions, and why some processes, such as respiration, do not seem to belong.

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The Digestive System: A Closer Look at Its Components

The gastrointestinal (GI) tract and the accessory organs.

The Gastrointestinal (GI) Tract

The GI tract, also known as the digestive tract or alimentary canal, is a long tube that extends from the mouth to the anus. The structure is built around a series of major organs along the entire chain of food coming from intake down to degradation and absorption. These organs include:

-Mouth: Digestion starts in the mouth. At present, food physically reduces to small bits by mastication, known as mechanical digestion. Simultaneously, the salivary fluid of salivary glands contains the amylase enzyme, which initiates the chemical cleavage of carbohydrates. Chewing is a way of increasing the surface area of the food particles to allow the activation effect of the digestive enzymes.

-Esophagus: Following the food has been chewed and mixed with saliva, it is swallowed and is propelled down the esophagus by peristaltic - a repetitive, voluntary, wave-like the contraction of the esophageal striated muscle. Hence, food may get into the stomach through the force of gravity.

-Stomach: The stomach is a muscular, hollow organ that acts as a mixing and holding tank for food. Food is moved into the stomach while homogenization of gastric juice containing hydrochloric acid and pepsin is occurring in the lower esophageal sphincter. These compounds hydrolyze food, mostly protein, into peptides. Stomach acid adds further levels of bactericidal action, which could have been consumed in the food. Stomach has a protective mucosa that is not auto-digested.

-Small Intestine: After food has been partially digested in the stomach, it moves into the small intestine, which is divided into three sections: the duodenum, the jejunum, and the ileum. Small intestine is the main site of nutrient absorption. After food is ingested in the duodenum, pancreatic digestive enzyme and bile secreted by the liver respectively participate in subsequent hydrolysis of food. The surface of the small intestine epithelium is covered with numerous small finger like projections, known as villi, to increase surface area of absorption, respectively. Nutrients such as proteins, carbohydrates, fats, vitamins and minerals are absorbed through the villi into the bloodstream, where they are transported to various parts of the body.

-Large Intestine (Colon): Once most of the nutrients are absorbed, the residue of indigestible fiber moves into the large intestine. Here, water and electrolytes are reabsorbed and the remaining substance is compacted to waste that is converted to solid waste. The colon is inhabited by a very complex gut bacterial community that participates in degradation of certain fibers and fermentation (giving off gases) of food. The colon has a major responsibility for water and electrolyte homeostasis.

-Rectum and Anus: Rectum is the terminal part of gastrointestinal (GI) tract. It is a receptacle of feces, until it can come out of the body. The body sends a signal to evacuate when the rectum is distended. The anorectum, with the anal surface protected by the sphincters, regulates the defecation ejection from outside the body.

Accessory Organs of the Digestive System

Beyond the gastrointestinal tract, several accessory organs produce molecules that help with digestion. These organs are not directly involved in food processing, but they supply needed digestive enzymes and secretion.

-Salivary Glands: Oral cavity salivary glands release saliva containing the protein hydrolytic enzymes, such as amylase. Amylase begins starch hydrolysis as soon as it is in contact with oral food.

-Liver: The liver is the biggest internal organ of the human body and performs a variety of important functions. It secretes bile, which is used for digestion of fat and fat absorption. Bile is stored in the gallbladder and secreted into the duodenum with fat in the intestines. Liver is also involved in blood detoxification and nutrient storage.

-Gallbladder: Gallbladder is a small adjacent to the liver organ. For which they have been storing and releasing bile from the liver and delivering to the small intestine from which it participates in the digestion of lipids.

-Pancreas: Pancreas is a large gland situated at the posterior side of the stomach. It secretes proteases that hydrolize proteins, lipids and carbohydrates in the small intestine. In addition, the pancreas also secretes bicarbonate in an attempt to neutralize gastric acid to create an appropriate microenvironment in the small intestine for enzyme activity.

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Key Functions of the Digestive System

The main function of the digestion system is breakdown of food, extraction of nutrients and clearance of waste. Here’s a detailed look at the essential functions:

1. Ingestion

Ingestion is defined as the process of taking food and drink into the body. This process starts when food enters the mouth. Food is physically and chemically digested (chewing and saliva) in the mouth. Muscles of salivary glands produce and secrete hydrolytic enzymes (e.g. amylase) to degrading carbohydrates. The swallow mechanism feeds the food to the pharynx from where it goes down to the esophagus.

2. Digestion

Digestion is the food breakdown into constituent parts that may be absorbed by the body. It involves both mechanical and chemical digestion.

-Mechanical Digestion: In this process, food is physically broken down into smaller pieces. When the teeth grind food in the mouth and in the stomach, food is mixed by churning and mixed with digestive juice.

-Chemical Digestion: This involves the enzymatic degradation of food on a molecular level by of enzymes. For example, amylase in saliva begins to cleave starches, pepsin in the stomach cleaves proteins, and lipases in the small intestine participate in fat digestion.

3. Absorption

Absorption, after ileal exposure absorption, is hydrolytic to nutrients mostly in the small bowel. Microscopic protrusions, villi, expand the surface area of the small intestine, facilitating diffusion of nutrients through the epithelium to the blood vessel. The following nutrients are then delivered to cells in the body to serve as fuel, growth and repair.

4. Secretion

Digestive system functioning is based upon the secretion of digestive enzymes and juices which enable food to be disintegrated. Salivary glands, liver, pancreas and stomach, all contribute to the secretion of compounds facilitating digestion. For example the pancreas secretes lipases (for degradation of fats), the liver secretes proteases and carbohydrates (for degradation of proteins and carbohydrates) and the liver secretes lipases with emulsion capacity in the small intestine.

5. Excretion

Excretion is a removal process in which removal results from the body being unable to degrade the waste. Following small intestine absorption of nutrients, the remaining waste solution is discharged to the large intestine, where water and electrolytes are reabsorbed. The unextended portion is left in the body and is defecated from the rectum and anorectum.

A Function That Doesn’t Fit: Respiration

Although it is the digestive tract essential for both food processing and absorptive feeding, it should be pointed out that the digestive process, while not including other organs involved in the physiological function of respiration, may include other modes of absorptive feeding.

Respiration is the process of taking oxygen into the organism and expelling carbon dioxide from the organism. During that process, the greatest amount happens in the lung, where blood takes in O2 and delivers it to the tissue to be used in the production of energy. Cellular respiration takes place in the mitochondria, in the process of which oxygen is oxidized to break down glucose and produce energy (ATP).

Although they both play a vital role in supplying energy to the organism, they achieve this function in distinctly different ways:

Digestion is a process in which food is broken down to make the excretion of nutrients (glucose, proteins, lipids, and vitamins) possible.

Lunging is a physiological process of obtaining oxygen to produce energy from glucose inside the cell.

Thus while digestion and respiration are steps in that process for meeting the energy requirement of the body, the latter is not a function of the digestive system.

Conclusion: Which of the following is not a function of the digestive system?

The digestive system is one of the most intricate and vital human organ systems. It allows us to separate food, absorb the necessary nutrients, expel waste and helps us to recuperate so that it is able to supply up the energy required to sustain life. Although the digestive system is the cranial system of life, a functional separation is required as other physiology, for example, the one of the respiration system, cannot be made to that of the digestive system.

All of the body systems work together in harmony, each with unique contributions to the maintenance of a state of bodily health and fitness. Learning the functional identity of the digestive system, in turn, leads us toward making more informed decisions about health, nutrition and all other aspects of our life in a way that maintains the best possible conditions for our bodies.