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39EURASIAN JOURNAL OF MEDICAL AND NATURAL SCIENCES
Innovative Academy Research Support Center UIF = 8.3 | SJIF = 5.995 www.in-academy.uz
DIGESTIVE SYSTEM Ikramova Sabina Raimova Nozima Djuraeva Barno Gulamovna
https://www.doi.org/10.5281/zenodo.10464152
ARTICLE INFO
ABSTRACT
Received: 30th December 2023 Accepted: 05th January 2024 Online: 06th January 2024
KEY WORDS Digestive System,
Gastrointestinal Tract GI, Enzymatic Digestion,
Absorption, Peristalsis, Gastric Acid, Pancreatic Enzymes, Small Intestine, Colon Large Intestine, Dietary Fiber.
This professional article offers a comprehensive exploration of the digestive system, a complex and finely tuned mechanism responsible for breaking down ingested food into essential nutrients. From the mouth to the intestines, the article delves into the anatomical structures and physiological processes involved in digestion. Key concepts such as enzymatic actions, absorption, and the role of gut microbiota are discussed, providing valuable insights for medical practitioners, researchers, and individuals seeking a deeper understanding of digestive health.
Introduction. The digestive system, often likened to a complex symphony, orchestrates the intricate process of nutrient processing within the human body. This article embarks on an exploration of this vital system, from the initial intake of food to the absorption of essential nutrients, shedding light on its anatomical structures and physiological functions.
What is the digestive system?
The gastrointestinal tract, sometimes referred to as the GI tract or digestive tract, as well as the liver, pancreas, and gallbladder comprise the digestive system. The GI tract is a lengthy, winding tube that connects the mouth to the anus and is made up of multiple hollow organs. The mouth, esophagus, stomach, small, large, and anus are the hollow organs that comprise the GI tract. The digestive system's solid organs are the pancreas, liver, and gallbladder.
Three sections compose the small intestine. The duodenum is the name of the first portion. The ileum is at the end and the jejunum is in the middle. The colon, rectum, cecum, and appendix are all parts of the large intestine. A finger-shaped pouch that attaches to the cecum is called the appendix. The large intestine begins with the cecum. Next is the colon. The large intestine ends at the rectum.
Digestion is aided by the bacteria in your GI tract, also known as gut flora or microbiome. Your circulatory and neurological functions also contribute in part. Together, your digestive system's organs, hormones, blood, bacteria, and nerves break down the food and liquids you consume every day.
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The organs that take in and process food are referred to as the digestive system in humans. The intricate process known as digestion makes it possible for the body's cells to absorb the nutrients found in food.
All of the nutrients required by the body for good health are found in food, but they are bound together by large, complex compounds. The body breaks these compounds down into smaller components during digestion. The organization are able to enter cells as a result, requesting energy and other advantages.
How does digestion work, step-by-step?
First, the teeth, tongue, and saliva turn food into a bolus, which is small and liquid enough to pass through the esophagus.
The bolus then travels to the stomach, where it is converted into a paste known as chyme by enzymes, acids, and muscle action. The small intestine is where the chyme enters.
This is where 90% of the absorption comes from trusted sources. Nutritions pass through villi's capillaries and into the circulation. The nutrients then make their way to different body cells. Any food that is still there enters the colon, or large intestine.
As food travels through to the rectum, where it is ready for defecation, the body absorbs water.
Ways to maintain a healthy digestive system? Tips include:
• drinking plenty of water
• eating a varied diet with plenty of fresh vegetables and whole foods
• establishing regular bowel habits
• seeking medical help for any unexplained changes in digestion or bowel habits Starting at the lips, the digestive tract terminates at the anus. It consists of the mouth, or
oral cavity, which has teeth for grinding food and a tongue for kneading food and combining it with saliva; the throat, or pharynx; the esophagus; the stomach; the small intestine, which is made up of the jejunum, the ileum, and the duodenum; and the large intestine, which is made up of the sigmoid colon, which ends in the rectum, the ascending colon, the descending colon,
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and the cecum. The pancreas, the liver and its adjuncts, the gallbladder and bile ducts, the salivary glands, the gastric glands lining the stomach, and the liver itself are among the glands that contribute digestive juices. All of these organs and glands contribute to the physical and chemical breaking down of ingested food and to the eventual elimination of nondigestible wastes. Their structures and functions are described step by step in this section.
The lips and cheeks. The lips, two fleshy folds that surround the mouth, are composed externally of skin and internally of mucous membrane, or mucosa. The mucosa is rich in mucus-secreting glands, which together with saliva ensure adequate lubrication for the purposes of speech and mastication.
The cheeks, the sides of the mouth, are continuous with the lips and have a similar structure. A distinct fat pad is found in the subcutaneous tissue (the tissue beneath the skin) of the cheek; this pad is especially large in infants and is known as the sucking pad. On the inner surface of each cheek, opposite the second upper molar tooth, is a slight elevation that marks the opening of the parotid duct, leading from the parotid salivary gland, which is located in front of the ear. Just behind this gland are four to five mucus-secreting glands, the ducts of which open opposite the last molar tooth.
The roof of the mouth. The roof of the mouth is concave and is formed by the hard and soft palate. The hard palate is formed by the horizontal portions of the two palatine bones and the palatine portions of the maxillae, or upper jaws. The hard palate is covered by a thick, somewhat pale mucous membrane that is continuous with that of the gums and is bound to the upper jaw and palate bones by firm fibrous tissue. The soft palate is continuous with the hard palate in front. Posteriorly it is continuous with the mucous membrane covering the floor of the nasal cavity. The soft palate is composed of a strong, thin, fibrous sheet, the palatine aponeurosis, and the glossopalatine and pharyngopalatine muscles. A small projection called the uvula hangs free from the posterior of the soft palate.
The floor of the mouth. Only when the tongue is raised can one see the floor of the mouth. The ducts of the submandibular salivary glands open from the prominent, elevated fold of mucous membrane (frenulum linguae) in the midline that connects each lip to the gums. On either side of this fold is a slight fold known as a sublingual papilla. A ridge known as the plica sublingualis runs from each sublingual papilla, marking the upper border of the sublingual salivary gland (located beneath the tongue), onto which the majority of the gland's ducts open.
The gums. The gums are made up of mucous membranes that are joined to the membrane encircling the jaw bones by dense fibrous tissue. Every tooth's exposed portion, or base of the crown, is encircled by a collar made of rising gum connective tissue. Supplied with blood gum tissues receive branches from the alveolar arteries, which supply the teeth and the spongy bone of the upper and lower jaws where the teeth are lodged. These arteries are named alveolar because of their connection to the tooth sockets, or alveoli dentales.
The teeth. The teeth are the white, hard structures that are part of the mouth. The teeth of various vertebrate species are sometimes specialized and are typically used for mastication. For example, snakes have extremely thin, sharp teeth that typically curve backward; these teeth are used for prey capture rather than chewing because snakes swallow their food whole. Compared to primates, including humans, carnivorous mammals like cats
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and dogs have sharper teeth. Their canines are longer, and their premolars—which are better suited for cutting and shearing—don't have flat grinding surfaces. On occasion, the more posterior molars are lost. However, the large, flat premolars and molars with difficult ridges and cusps found in herbivores like cows and horses; The dogs are frequently completely missing. Meat-eating animals like snakes, dogs, and cats typically have sharp, pointed teeth that are poorly suited for chewing, whereas herbivores have broad, flat teeth that are well suited for chewing. Teeth vary in shape because of functional adaptations. Although few animals are able to break down cellulose, herbivores must first break down the cellulose cell walls regarding the plant cells they consume in order for the contents of the cells to be exposed to the action of digestive enzymes. In contrast, meat contains animal cells that are directly susceptible to the activity of digestive enzymes because they are not covered in indigestible material. As a result, unlike herbivores, carnivores do not require as much chewing. Humans, who are omnivores (eaters of plants and animal tissue), have teeth that belong, functionally and structurally, somewhere between the extremes of specialization attained by the teeth of carnivores and herbivores.
Every tooth is composed of a crown and one or more roots. The crown is the visible part of the tooth that is above the gum line. The term "root" refers to the portion of the tooth that is not visible but is responsible for anchoring it in the jawbone. The forms of an animal's roots and crowns distinguish it from other animals. The teeth on one side of the jaw practically reflect the teeth on the other. The upper teeth are different from and complementary to the lower teeth. Humans usually possess two sets of teeth in their lifetime. The initial set, also known as the primary, milk, or deciduous dentition, is gradually acquired between the ages of two and three. The teeth of the secondary set gradually replace these ones as the jaws widen and grow. Each of the four quadrants of the mouth contains five deciduous teeth and eight permanent teeth, for a total of 32 permanent teeth that replace the 20 deciduous teeth.
The tongue. The tongue is a muscular organ on the floor of the mouth that is highly mobile and serves as an accessory organ for several motor functions, including swallowing, chewing, and speech. It can direct and hold food between the upper and lower teeth until mastication is finished, working in combination with the cheeks. Infants are able to suckle because of the tongue's ability to create a negative pressure inside the oral cavity. Taste buds, which are clusters of specialized epithelial cells on the tongue that transmit stimuli from the oral cavity to the central nervous system, are particularly significant as a peripheral sense organ. Moreover, some of the saliva required for swallowing is made up by the glands on the tongue.
The tongue consists of a mass of interwoven striated (striped) muscles interspersed with fat. The mucous membrane that covers the tongue varies in different regions. The tongue is attached to the lower jaw, the hyoid bone (a U-shaped bone between the lower jaw and the larynx), the skull, the soft palate, and the pharynx by its extrinsic muscles. It is bound to the floor of the mouth and to the epiglottis (a plate of cartilage that serves as a lid for the larynx) by folds of mucous membrane.
Stomach. Anatomy
The stomach has three layers of muscle: an outer longitudinal layer, a middle circular layer, and an inner oblique layer. The inner lining consists of four layers: the serosa, the
muscularis, the submucosa, and the mucosa. The mucosa is densely packed with gastric glands, which contain cells that produce digestive enzymes, hydrochloric acid, and mucus.(more)
Why does the human stomach rumble?
Learn why the human stomach rumbles.
Food and liquids from the esophagus are received by the stomach, which holds them until they are ground and combined with gastric juice to make the food particles more soluble and smaller. The stomach's primary duties include starting the breakdown of proteins and carbohydrates, turning food into chyme, and periodically releasing the chyme into the small intestine once the mixture's physical and chemical state is made suitable for the subsequent stage of digestion. The stomach is situated just below the diaphragm in the upper left portion of the abdomen. The anterior abdominal wall, the liver, and a section of the diaphragm are situated in front of the stomach. The pancreas, left kidney, left adrenal gland, and spleen are located behind it. The stomach's left side is convex and its right side is essentially concave. The greater curvature is associated with the convex border along with the lesser curvature with the concave border. The stomach's mucosal lining forms numerous rugae, or longitudinal folds, when it is empty; these folds normally vanish when the stomach is widened.
Gastrointestinal Tract (GI): The Conduit of Nutrient Journey
The GI tract, a series of hollow organs extending from the mouth to the anus, serves as the primary pathway for nutrient processing. This section provides an overview of each segment—mouth, esophagus, stomach, small intestine, and large intestine—highlighting their distinct roles in digestion and absorption.
Enzymatic Digestion: Breaking Down the Culinary Complexity
Digestive enzymes, secreted at various points along the GI tract, play a pivotal role in breaking down complex food molecules into simpler forms. The article delves into the specific actions of enzymes like amylase, lipase, and protease, showcasing their contributions to the digestive process.
Absorption and Nutrient Transport: Crossing the Biological Border
Stomach
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The small intestine, a critical site for nutrient absorption, is explored in detail. This segment elucidates the mechanisms of nutrient transport across the intestinal lining into the bloodstream, emphasizing the significance of this process in ensuring the body receives essential components for growth and energy.
Gut Microbiota: Allies in Digestive Harmony
The article navigates the fascinating world of gut microbiota, the diverse community of microorganisms residing in the digestive system. From aiding in digestion to influencing immune function, the role of these microbial allies is uncovered, emphasizing the symbiotic relationship between humans and their gut microbiome.
Digestive Disorders and Dietary Considerations: Navigating Challenges
An exploration of digestive health would be incomplete without addressing common disorders such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). This section also touches on dietary factors, including the importance of fiber and the role of probiotics in maintaining a healthy digestive system.
Pancreatic Enzymes: The Powerhouses of Digestion
The pancreas, a crucial organ nestled behind the stomach, plays a central role in the digestive process by secreting a potent cocktail of enzymes. These enzymes, collectively known as pancreatic enzymes, are indispensable for breaking down various macromolecules in ingested food, facilitating their absorption and utilization by the body.
Types of Pancreatic Enzymes:
Amylase: This enzyme targets carbohydrates, specifically breaking down complex sugars like starch into simpler sugars such as maltose and glucose. Amylase begins its action in the mouth and continues its work in the small intestine.
Lipase: Specialized in lipid digestion, lipase is responsible for breaking down fats into fatty acids and glycerol. Lipase is particularly active in the small intestine, where it ensures the efficient absorption of dietary fats.
Protease: Proteins are complex molecules, and protease enzymes break them down into amino acids, the building blocks of proteins. Trypsin, chymotrypsin, and carboxypeptidase are examples of protease enzymes secreted by the pancreas.
Activation of Pancreatic Enzymes:
Pancreatic enzymes are secreted in an inactive form to prevent them from digesting the pancreas itself. They become active once they reach the small intestine. Trypsinogen, for instance, is converted into trypsin by an enzyme called enterokinase present in the small intestine. This activation cascade ensures precise control over the digestive process.
Regulation of Pancreatic Enzyme Secretion:
The release of pancreatic enzymes is tightly regulated. Hormones, such as cholecystokinin (CCK) and secretin, play key roles in stimulating the pancreas. CCK is released in response to the presence of fats and proteins in the small intestine, while secretin is triggered by acidic chyme entering the duodenum. Together, these hormones orchestrate the secretion of pancreatic juices rich in enzymes.
Clinical Significance:
Disruptions in the production or activity of pancreatic enzymes can lead to malabsorption and nutritional deficiencies. Conditions like chronic pancreatitis, cystic
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fibrosis, or pancreatic cancer can compromise the pancreas's ability to produce enzymes adequately.
Supplementation and Therapy:
In cases of pancreatic insufficiency, where the pancreas does not produce sufficient enzymes, enzyme replacement therapy may be employed. Pancreatic enzyme supplements containing amylase, lipase, and protease are administered to aid digestion and nutrient absorption.
Research and Development:
Ongoing research focuses on understanding the intricate regulation of pancreatic enzyme secretion and exploring potential therapeutic interventions for digestive disorders. Advances in enzyme replacement therapies and targeted drug delivery systems aim to enhance the management of conditions related to pancreatic insufficiency.
In conclusion, pancreatic enzymes are indispensable for the digestion and absorption of nutrients. Their intricate regulation, activation, and the vital role they play in breaking down macromolecules underscore their significance in maintaining optimal digestive health. Advances in our understanding of pancreatic enzymes continue to pave the way for innovative therapeutic approaches and improved patient outcomes.
Conclusion: As we conclude this journey through the digestive system, the article emphasizes the importance of maintaining digestive wellness. It advocates for a balanced diet, hydration, and mindful eating habits to support the intricate processes of digestion and absorption, ultimately contributing to overall health and vitality.
This comprehensive exploration serves as a valuable resource for medical practitioners, researchers, and individuals keen on understanding the intricate workings of the digestive system and promoting digestive health.
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