Since humans are heterotrophs, they rely on the food they eat to provide their bodies with the energy needed to carry out vital cellular functions. Humans require six essential nutrients for survival: water, vitamins, minerals and three macronutrients; carbohydrates, lipids and proteins (Bowers et al, 2002). These macronutrients are often ingested as polymers, long chains of repeated basic molecular units called monomers, which are too large to be absorbed by cells directly. The digestive system is responsible for breaking these polymers down into monomers so that the nutrients can be absorbed into the bloodstream and transported throughout the body. This breakdown of nutrients is achieved through mechanical and chemical digestion. Mechanical digestion for all macronutrients begins in the mouth and it involves the physical breakdown of food through tearing, chewing, mixing and churning (Bowers et al., 2002). Mechanical digestion prepares the food for chemical digestion by increasing the surface area upon which the digestive enzymes can act (Bowers et al., 2002). In chemical digestion, polymers are broken down chemically through the process of hydrolysis with the aid of digestive enzymes which accelerate the process (Collin County Community College, 2014):
Protein + water protease amino acids
Complex sugar + water carbohydrase simple sugars
Fats + water lipase glycerol + fatty acids
Polymers are formed during dehydration synthesis reactions, as a covalent bond forms between two monomers when a water molecule is lost (Collin County Community College, 2014). In hydrolysis, the covalent bond between monomers in a polymer is broken by the addition of a water molecule as the hydrogen in the water molecule attach...
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...nzymes to digest them. In chemical digestion, hydrolysis breaks the bonds between monomers with the aid of enzymes, secreted throughout the digestive tract and by the accessory organs, to catalyze the process. These enzymes functional optimally in certain areas of the alimentary canal based on the pH of the surroundings. The monomers of carbohydrates and proteins are then absorbed into the mucosal cells of the microvilli lining the small intestine and diffuse into the capillaries surrounding the villi where they are transported in the bloodstream to cells in the body. Most of the nutrient absorption occurs in the duodenum and jejunum (University of Illinois Chicago, 2004). Lipids are too large to diffuse into the capillaries and are reassembled into triglycerides and enter the lymphatic system. Any undigested matter is eliminated from the digestive system as feces.
The sphincter at the conclusion of the stomach recognizes as the pyloric sphincter that controls the food from entering the small intestines. As the food enters the stomach, the chemical digestion continues by other enzymes, acid, and bile that released during this process. Different enzymes work on different food components. The stomach has three primary functions the storage of food, the mixing of food and controlled emptying of food into the small intestines. The chemical digestion occurrence within the stomach is mainly from the enzymes released in the stomach. Pepsin is the enzyme that begins the disintegrate of protein. The stomach also discharges gastric lipids that act on butterfat. Tributyrinase anatomizes the fat within the cheese and the turkey and bread of the sandwich into tributyrin. The tributyrin undergoes more chemical reaction transform it into glycerol and fatty acids. The turkey, cheese lettuce and bread are further broken down by pancreatic amylase digesting the starches breaking them down into disaccharides, lactose, sucrose, and maltose. These are further broken down into monosaccharides, lactose to glucose and galactose. Sucrase to broken down to glucose and fructose. Maltase breaks down to maltose to form two molecules of glucose. The protein in the turkey and cheese is broken down by Trypsin and polypeptides to dipeptides. A chemical reaction in body dilapidated
The digestive system otherwise known as the gastrointestinal tract (GI tract) is a long tube which runs from the mouth to the anus. It operates to break down the food we eat from large macromolecules such as starch, proteins and fats, which can’t be easily absorbed, into readily absorbable molecules such as glucose, fatty acids and amino acids. Once broken down, these molecules can cross the cells lining the small intestine, enter into the circulatory system and be transported around the body finally being used for energy, growth and repair.
The food digestion plays an undeniably important role in our body system, which is the main way for the human kind to gain nutrients and energy in order to growth, repairs the body cells, and carry out the daily routine (National Institutes of Health, 2013). The foods and drinks that people consume are required to be turned into the smaller nutrient-molecules before the blood absorbs and carries the various nutrients such as carbohydrates, proteins, fats, vitamins and minerals to the body cells (National Institutes of Health, 2013). According to National Institutes of Health (2013), the decomposition of food nutrients are completed through the digestive system which form by the gastrointestinal (GI) tract, also defined as digestive tract, and along liver, pancreas and gallbladder as well. The GI tract is made up of a series of hollow organs with the connection from mouth to anus, which consisting buccal cavity (mouth), esophagus, stomach, small intestine, and large intestine. Based on Batrisya (2013), the food digestive process are classified into four stages, that are ingestion, digestion, absorption, and egestion or elimination (refer to Figure 1 in Appendix 1).
Peristalsis that was mentioned earlier in the oesophagus is also used in the small intestine to help move food through and mix it with digestive secretions from the pancreas and the liver. Its first responsibility is the process to continuously breakdown, then the second and third responsibility is the absorption of nutrients into the bloodstream. As chyme moves through the small intestine, many of the molecules are absorbed in to the bloodstream and the small intestine has a very efficient way to help in this process. The inside of the small intestine has finger-like projections called villi and these raise the surface area of the gut. The contents of the small intestine begin semi-solid and then finish in a liquid form after passing through the organ. Bile enzymes, water and mucus contributes to the change in consistency. Then once the nutrients have been absorbed and any leftover food residue liquid has been passed through the small intestine, it will then move onto the large intestine through the ileocecal
Digestion is defined as the process of transforming foods into unites for absorption. The Digestive System is a complex network of organisms that have six major processes: The digestion of food, the secretion of fluids and digestive enzymes, the mixing and movement of food and waste throughout the body, the digestion of food into smaller pieces, the absorption of nutrients, and the excretion of wastes (Inner Body (1).)
...ve eaten, to break down the food into a liquid mixture and to slowly empty that liquid mixture into the small intestine. Once the bolus has entered your stomach it begins to be broken down with the help of the strong muscles and gastric juices which are located in the walls of your stomach. The gastric juices are made up of hydrochloric acid, water, and mucus- and the main enzyme inside of your stomach is what is known as pepsin, which needs to be surrounded in an acidic setting in order to do its job, that is to break down protein. Once the bolus has been inside of your stomach for long enough it begins to form into a liquid called chyme, and what keeps the chyme from flowing back into our esophagus are ring shaped muscles known as sphincters located at the beginnings and ends of the stomach and they have the task of controlling the flow of solids and liquids.
Imagine you are eating a sandwich containing wheat bread, ham, lettuce, and Swiss cheese. Do you ever wonder where the nutrients go from all of the previous listed ingredients? Well, when a bite of this sandwich is taken, the mouth produces a saliva enzyme called amylase. This enzyme immediately goes to work by breaking down the carbohydrates that are in the bread. Once, the bite is completely chewed, the contents then are swallowed and go down the esophagus and begin to head towards the upper esophageal sphincter and the is involuntarily pushed towards the stomach. The next passage for the sandwich is to go through the lower esophageal sphincter; which transports the sandwich into the stomach.
The digestive system is important for breaking down food and turning it into nutrients. The body uses the nutrients for energy, growth, and cell repair. The food and drinks that a person must be changed into smaller molecules of nutrients before the blood absorbs them and carries them to cells throughout the body. The body breaks down nutrients from food and drink into carbohydrates, protein, fats, and vitamins. Compared to the other systems in the body, the digestive system is one of the most diverse and important. According to Robert Sullivan the digestive system is a set group of organs whose function is based on the process of turning food, absorbing nutrients for energy and getting rid of the bodies waste (Sullivan, 2008, p.33). The organs
During digestion, the body breaks down food into smaller molecules that could then be used by the body’s cells and tissues in order to perform functions. This starts off in the mouth with the physical movements of chewing and the chemical breakdown by saliva. Enzymes in the stomach break food down further after traveling from the mouth through the esophagus. The food from here then moves into the small intestine, where pancreatic juices and enzymes dissolve proteins, carbohydrates, and fibers, and bile from the liver breaks down fats into these small molecules. Any portion of the fibers or food that were unable to be broken down are passed from the small intestine to the large intestine, which is where the digestive tract transitions into the excretory tract, then the colon and out of the rectum. Any liquids that have been stripped of their nutrients by the body proceed from the stomach to the kidneys. In the kidneys, sodium ions (Na+), uric acid, and urea are exchanged with water, which moves urinary bladder and is excreted through the
Absorption is the way of digesting the food molecules into the small intestine. This process of absorption pass throughout the wall of the small intestine into the bloodstream. The bloodstream carried out all important nutrients to the
The synthesis of polymers starts with ethylene, (or ethene). Ethylene is obtained as a by-product of petrol refining from crude oil or by dehydration of ethanol. Ethylene molecules compose of two methylene units (CH2) linked together by a double carbon
When eaten, protein is broken down into amino acids. Proteins and amino acids are used for almost every metabolic process in the body, and are the building blocks for every tissue in your body.
...he Buttermilk White bread. The food makes its way to the transverse colon and extra nutrients are released form the cellulose of the undigested particles. It continues on to the descending colon. There I start to manufacture vitamin K and other B-complex vitamins. Those are then absorbed into my large intestine.
It is then secreted within the small intestine where it helps to break down ethanol, fats and other acidic wastes including ammonia, into harmless substances.
If you frequent health forums or fitness blogs, you'll have read the word “macros” before. The word is short for macronutrients. That leads to the question, “what are macronutrients?”