Digestion of foodstuffs is a vital process for the organism’s proper functioning and an irreplaceable part of the metabolism. Metabolism, in turn, provides the bodies of living organisms with energy and valuable substances, which ensures activity and health. Digestion is a process that is designed to help the body absorb valuable substances, vitamins, minerals, proteins, fats, and carbohydrates by reforming their structure and making them more straightforward (Process of Digestion, n. d.). Therefore, the process of digestion is complex and involves many chemicals that the body produces and the specially designed system of organs.
Digestion starts before the complex processes in the inner structures of the body – from the oral cavity. The intaken food is chewed, teeth break it into small pieces, and the saliva hydrates it to continue the process of digestion. Saliva brings amylase, an enzyme that hydrolyzes the starch, and lysozyme, which is antibacterial and prevents infections (Process of Digestion, n. d.). The moisture and chewed food, called a bolus, is swallowed with the help of the pharynx to continue digestion (Process of Digestion, n. d.). Then, the process starts in the stomach and lasts up to 5 hours. The main active substances here are mucus secreted by mucus neck cells, proenzyme pepsinogen secreted by the peptic cells, hydrochloric acid secreted by oxyntic cells (Digestive system processes: Chemical and physical, n. d.). The process involves mixing the food with gastric juices, and the stomach muscle maintains this mixture; the food mass is called the chyme afterward (Digestive system processes, n. d.). The stomach and its enzymes mainly provide the digestion of proteins.
More profoundly, the processes that the gastric juice and enzymes provide are the following. Hydrochloric acid provides the acidic pH; pepsin turns protein into peptones and proteoses, casein turns into peptides (Process of Digestion, n. d.). Later, in the small intestine, chyme is mixed again due to the movement of the small intestine and meets more enzymes: amylase, enterokinase, trypsin, chymotrypsin, carboxypeptidase, elastase, and nucleases (Rakshitha, n. d.). These enzymes and substances also contribute to the further digestion of the food and its simplification for the cells to absorb.
Additionally, the small intestine ensures the processes connected with glucose digestion. Maltase turns maltose into glucose; sucrose does the same to sucrose to get fructose, lactase turns lactose into glucose and galactose, peptides are turned into amino acids by aminopeptidases (Digestive system processes, n, d.). After that, bile provides the emulsification of fat globules, and pancreatic lipase helps break down triglycerides to glycerol and fatty acids (Rakshitha, n. d.). The food becomes suitable for cell absorption at this stage, and only some particles are moved to the large intestine.
The large intestine is not as active in providing substances for digestion as the small intestine. Its primary function is ensuring the absorption of minerals and water (Digestion of foods, n. d.). The waste food particles called fecal matter are then removed from the body (Digestion of foods, n. d.). Generally, the whole system is controlled by hormones, which stimulate the alimentary canal to work correctly and transfer signals from the brain to the organs (Rakshitha, n. d.). At the same time, nerve signals are sent back to the brain to indicate hunger (Digestion of foods, n. d.). In other words, the digestive process is controlled by the nervous system and hormones.
To conclude, the digestion system of the human body is well-designed for maintaining the proper functioning of the organism. All of the system’s elements are interconnected and interdependent, meaning that the process requires a coherent activity of the involved elements. The enzymes that take part in digestion provide the body’s cells with properly dissolved useful substances required for energy balance and metabolism in general.
References
Digestion of foods. (n. d.). Raw Food Explained. Web.
Digestive system processes: Chemical and physical. (n. d.). Digesting of Foodstuffs, 599-612. Web.
Process of Digestion. (n. d.). Toppr.com. Web.
Rakshitha, S. (n. d.). Digestion & absorption of foodstuff in human beings. Biology Discussion. Web.