Enzymes Of The Digestive System


Digestion is associated with the breaking down of the large food particles into pieces so that it can be easily be absorbed as well as assimilated into the body. This presentation is going to determine the structure and function of digestive system, with reference to the functions of the different enzymes that are associated with the digestive process. Moreover this presentation will highlight the feature of the chemical and mechanical digestion process and different enzymes that are associated with the two types of digestions. This study will also describe the food group of the balanced diet by demonstrating their actual sources.

Main aspects that the study highlights are as follows: Structure of the digestive system’ functions of the digestive system Chemical and mechanical digestion process Functions of the different enzymes in the overall digestion process Constituents food groups in a balanced diet with providing example of their sources


Human digestive system is made up of accessory digestive organs (such as mouth, salivary gland, pancreas, gallbladder and liver) and gastrointestinal track. Mouth is also known as the oral cavity which is starting point of the digestion in the human digestive process. As stead by McCancem and Huether (2018), mouth consists of many different organs which are associated with the digestion process such as teeth, tongue and salivary gland. It is ‘Y’ shaped fibro muscular tube which is situated at the terminal end of the mouth. Pharynx is also act as the major part if the respiratory system (Zhang et al. 2015). Oesophagus is the small tube like structure which is connected to the pharynx in one ends and its other end is connected to the gastrointestinal track. As stead by McCancem and Huether (2018), esophagus is the upper part of the gastrointestinal track, that supplies the swallowed foods along with its length.

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Stomach can be considered as the muscular bag that is located at the left side of the abdominal cavity and beneath the diaphragm. It is the J shaped structure that is connected to the oesophagus at the upper end and to the duodenum at the terminal end. Stomach consists of four major parts such as cardia, body, fundus and pylorus (Treuting et al. 2018). Cardia is the part of the stomach which connected it upper end to the oesophagus. On the other hand, pylorus is the lower end of the stomach that connects it to the duodenum.

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Fundus is dome shaped which is situated above and to the left of the cardia. Body is the major part of the stomach. Pyloruous is funnel shaped structure which has the two parts such as pyloric canal and pyloric antrum. Pyloric canal is the narrower end of the pylorus which is connected to the duodenum. Pyloric antrum is connected to the body the body of the stomach.

Pancreas is the larger gland in the human digestive system which is situated at the posterior to the stomach (Zhang et al. 2015). It is 12-15 cm long structure that consists of tree structure head, body and tail. Its head is curve of the duodenum thereby connecting this structure with the duodenum Panacreas is considered as the mixed gland, which acts as both the endocrine and exocrine gland. Adult pancreas contains nearly 200,000-20,00,000 cells that are located in the endocrine pancreas , these cells are known as islet of Langerhans.

Small intestine is the ling tube which is 10 ft long. It is the lower part if the gastrointestinal track. As stead by Treuting et al. (2018), small intestine is the narrow, coiled and folded tube like structure that is extending from eth stomach ad goes towards the large intestine. It is highly convoluted structure which is located at the lower and central part of eth abdominal cavity. There is the membranous material mesentery that provides proper support to the intestine. Small intestine consists of three different regions such as duodenum, jejunum and ileum (Ohno et al. 2016). Jejunum is the first area of the small intestine that is connected to the stomach. It is 23 to 25 cm long. The second part of the small intestine is jejunum that comprises of the two fifth of the entire track. The third and last part, the ileum, is situated at the lower abdomen. The wall of the ileum is narrow and blood supply is limited in this sections

Large intestine is the terminal part of the gastrointestinal track. It is consists of colon and rectum. Colon is tube like structure which is nearly 1.5 m long, which about the one quarter eth larger intestine. Colon is the largest part in the large intestine, which is connected with the illeocecal valve in the upper end and to the anal verge at the lower end. Colon has three parts such as the ascending, transverse and descending colon (Pal and Karmakar, 2018). Rectum is the 10 cm long tube which is situated after the colon. It starts with the peritoneal reflexion and ends into the anal canal. It has upper and lower demarcations, which plays important roles in the digestive process.

Mouth assist in chewing the foods, to breaks down the large particle into small particles so that large foods can easily be absorbed as well as assimilated into the saliva. During the chewing process saliva mixes with the food particles and makes it easier to absorb (Ohno et al. 2016). Pharynx: Pharynx acts as both the digestive and the respiratory track. In case digestion, Pharynx permits the food particles and the liquid to move towards the oesophagus (Pal and Karmakar, 2018). Moreover, Pharynx has the cavity which consists of the different muscles can assist the food particles to molves towards to gullet, oesophagus and the stomach. Oesophagus: Oesophagus acts as the hollow tube into which the food particles are slipped down like the water slide. Moreover, it consists of different muscles that assist eth foods to move towards the stomach (Goodheart and Bely, 2017). The process in which the oesophagus assist eth the food particles to move towards the stomach through contracting and expanding the muscle is known as the peristalsis.

Stomach performs three major functions which are as follows: Digestion of foods Secretion if the gastric juice and the mucus that assist eth stomach to coat it’s lining that are important for preventing the erosion of the gastric juices. Secretion of the gastric hormones which is associated wit digestion of the food particles and making the food article more liquid that can be easily absorbed into the cells (Cheng et al. 2018). Stomach is also associated with regulating the proper rate of the partially digested foods that is delivered to the small intestine.

Pancreas is associated in predicting the different enzymes and chemicals that are associated with performing the proper digestion process:” Exocrine portion of the pancreas produces the following enzymes that are associated with the digestion of the carbohydrates, fats and protein s particles. Chymotrypsin and trypsin are associated with digestion of protein particles. Amylase is associated with braking down of the carbohydrates Lipase that is secreted from eth pancreas is associated with the digestion of the fats and fatty acids and the cholesterols (Cheng et al. 2018). Endocrine system of pancreas is associated with secreting eth following enzymes which also take part in digestions; Insulin: This hormone is secreted from the beta cells of the islets of Langerhans, which maintain the glucose level into the blood by moving the glucose from eth blood into the cells. Moreover insulin also assists the liver cells to absorb glucose as glycogen which is associated with maintaining proper balance of the blood sugar in the human blood. Glucagon: It is secreted from the alpha cells of eth pancreas which is associated with maintaining eth glucose level in the blood by transforming eth glycogen into glucose Pal and Karmakar, 2018. When eth glucose level falls in the blood, this hormone assists the stored glycogen to transform into the glucose and goes back the blood thereby maintaining the proper balance of eth glucose within the blood.

In the small intestine part the 90% of the digestions and absorption takes place. On the other hand only 10% of the absorption and digestion takes place in eth large intestine. Major function of the small intestine is the absorbing the minerals and nutrients from the food particles. Mechanical digestion of food particles, that is chewing, missing, grinding of the food occur in the mouth and stomach. The chemical digestion occurs in the intestine, in which different chemical and enzymes tale parts in digestion of different food particles. Proteins, amino acids and peptides are digested through the enzymes such as trypsinm, chymotrypsin that is secreted by the pancreas.

Lipase is the enzyme that is associated with braking eth fats into fatty acids and glycerides. In addition to this the bile is secreted from the lives and gall bladder which is associated with the digestion of eth lipids (Pal and Karmakar, 2018). Digestion of the carbohydrates occurs in the small intestine through the enzyme amylase this enzyme breaks down the carbohydrates into the oligosaccharide and the monosaccharide. Large intestine: Large intestine is associated with absorption of the water, which assist in the formation of the stool (Ohno et al. 2016). Large intestine also assists in absorption of vitamins that are made by the bacteria living in the large intestine. Mucosa of large intestine secrets bicarbonates in order to neutralise the acidity that cab be resulted from eth production if the fatty acids

As stead by Ohno et al. (2016), mechanical digestion is the physical breaking down of the food particles into the small segments through the act of chewing, churning and the segmentation. In case of eth mechanical digestion mouth is associated with the chewing process, stomach is associated churning and small intestine is associated with the small intestine. Chewing (mouth): Mouth is involved in chewing process which is done by the grinding operation of the teeth Tongue is associated with pushing the food towards the backside of the throats, in which it moves towards the oesophagus as the bolus Epiglottis acts as the restriction for preventing the movement of bolus into the trachea. On the other hand uvula prevents the entering of eth bolus into the nasal cavity Churning (stomach): There are specific muscles in the wall of eth stomach which associated with mixing of eth food particles with eth digestive juices in terms of making the food easier to be absorbed as well as assimilated (Goodheart and Bely, 2017). In the stomach food is digested with the actions of different enzymes which transform the bolus into the creamy paste if the foods which is known as Chyme The chyme enters into the small intestine (duodenum) in which teh absorption occurs Movement of the foods: In case of the mechanical digestion, the movement of the food particle in the oesophagus towards the stomach and pancreas is known as the peristalsis (Treuting et al. 2018). In terms of conducting peristalsis movement of the foods there are responsible some muscle such

Segmentation is the contraction as well as relaxation of the non-adjacent parts of eth circular smooth muscles which is located on the intestinal; wall (Goodheart and Bely, 2017). Segmentation contradiction assists eth movement of the chime towards both the direction, allowing the proper mixing of food with the different digestive juices. Segmentation also helps the physical digestion of the different food particles, by assisting the bidirectional propulsion of chime as well as of bolus. This bidirectional flow is important for the bolus and chime to transform into more liquid and absorbable food.

Chemical digestion is the process in which the food is transformed in to the smaller and simple form by the action of different chemical agents such as hormones, bile and enzymes (Treuting et al. 2018). Stomach acids: In case of chemical digestion, stomach plays an important role. Stomach consists of the gastric glands that release the digestive acid in order to create the lower pH environment. Acidic environment of the stomach glands is associated with denature of the different macromolecules and the proteins (Ohno et al. 2016). . Stomach epithelium consists of the mucous membrane which restricts the action of the acid ion term of damaging the gastric lining of the stomach wall. Alkaline compounds such as bicarbonate ions ate secreted from the pancreas which is associated with neutralising the acids, thereby maintaining eth acid balance within the intestine. Bile: Bile is the digestive fluid that is secreted from the liver and stored into the gallbladder before releasing into the intestine for digestion process. Bile consists of eth bile salts that make chemical interaction with the fats and fats globules and breaks them into the smaller droplet. The process of breaking down of the fats into the small droplets is known as the emulsification. Emulsification of the fat droplets enhances the surface available for Lipase in terms of digesting the fat particles. Enzymes: As stead by Pal and Karmakar (2018), enzymes are considered as eth biological catalysts that can increase the rate of the chemical reaction by presenting during the process. Different enzymes are associated with the digestion process in different part if the digestive track: Carbohydrate:

Carbohydrates digestion starts at the mouth in which Amylase is secreted from the salivary gland. Amylase is associated with the digestion of starch. In pancreas amylase is also secreted in term of digestion of carbohydrates within the small intestine. For digestion of the cellulose there is no enzyme produced in the human body. Therefore the entire cellulose is remained undigested. Protein digestion: For protein digestion, stomach secrets the pepsin, which breaks down the protein molecules into the smaller peptides, which is known as the protease. Endopetidase acts on the smaller poly peptide chain that enters into the small intestines and transforms the polypeptides into the smaller peptides. Lipids: Lipase enzyme is associated with the retaking down of fats. Through the emulsification process, the fat globules react with bile and transformed into the lipid droplets (Goodheart and Bely, 2017). Smaller fat droplets are then absorbed by the action of the lipase in eth pancreas. Two enzymes: Pepsin: Pepsin is the end peptidase that breaks down the protein molecules into the smaller peptides. Pepsin is produces in the stomach and it is the important digestive enzyme (Cheng et al. 2018). Proenzyme of pepsin, the pepsinogen, is release by the chief cells of the stomach. Then the proenzyme is mixed with the gastric juice and hydrochloric acid and then activates into the pepsin. Amylase Amylase is present in the human saliva and is associated with the digestion of the stomach (Cheng et al. 2018). Amylase catalyses the hydrolysis process of eth starch thereby transforming it into the sugar or glucose.

Balanced diet is the healthy foods that cover all the five main food groups that assist the body it get the proper nutrients and the energy in terms maintaining the normal mental and physical growth (Michie, 2018). The balanced diet includes the following food groups:
Fruits and vegetables: Based on the NHS guidelines, it is important for individual to take 80 g portion of the fruits and vegetables a day (Lais et al. 2016). Fresh, dried, canned and frozen fruits and vegetables can be included into eth balanced diet. In case of the vegetables, curry, soup and strews can be allowed to the balanced diet
Starch foods: Potatoes, breads, rice and pasta can be great sources of the starch, which can assist eth individual to get proper carbohydrates (Bianchi et al. 2016). Daily intake of 3 g beta glucan and fibre can be good sources if the carbohydrates. Nion-dairy protein: Fish, beans, meat, pulses, nuts and eggs are the good source of the non dairy protein
Milk and dairy products: For having the healthy balanced diet individuals can take the yogurt, cream, butter and cheese (Lais et al. 2016). Milk and vegetable oil are also the good source of the saturated fats. Sugar and fats: For having the proper sugar and fats in the balanced diet, NHS states that Individual can take animal oil such as butter and sugar (Bianchi et al. 2016). Based on NHS guidelines:’ a man needs to eat 30g saturated fat a day A women needs to eat 20 g of the saturated fat a day.

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From the above discussion, it can be concluded that, digestive system consists of different parts such as mouth, pharynx, oesophagus, pancreas, stomach and intestine. Different functions are associated with the different digestive parts. Different enzymes such as pepsin, amylase and lipase are involved in digestion of digestion of eth different foods particles. Balanced diet is the diet which covers the five major food groups. Therefore, healthy living is associated with having healthy and balanced diet everyday, which assist individual to have the normal growth.

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