Parts And Function Of The Digestive System – Medically reviewed by Cynthia Taylor Chavousty, MPAS, PA-C – Tim Newman – Updated May 23, 2023

The human digestive system refers to the organs that take in food and break it down. Digestion describes a complex process that allows nutrients to enter the body and its cells.

Parts And Function Of The Digestive System

Food contains all the nutrients the human body needs, but they are bound together by large, complex compounds. During digestion, the body breaks down these compounds into smaller parts. This allows them to enter cells, providing energy and other benefits.

Digestive System Model Demonstrating Sequence And Length Of Organs

This article explains how the body digests food from the time it enters the mouth to the time it leaves the body. It also suggests some tips for healthy digestion and identifying problems.

The human gastrointestinal tract, also called the alimentary canal, is about 30 feet (9 meters) long in adults.

In addition, the following organs support digestion, for example by chewing or adding enzymes and other secretions that allow the body to absorb nutrients:

Together, these organs provide mechanical processing, the secretion of enzymes and bile that help break down compounds, and the elimination of waste.

Colon (large Intestine): Anatomy, Function, Structure

Chewing and amylase digestion turn food into a small, round blob or bolus. This allows a person to swallow it easily.

After swallowing, the bolus enters the esophagus, where gravity and muscle contractions help move it down into the stomach through a process called peristalsis.

However, acid can damage the lining of the stomach, so some cells produce mucus to protect the lining from damage.

The stomach does not absorb many nutrients from the chyme into the bloodstream, so the chyme passes through the pyloric sphincter into the small intestine.

The Structure Of The Digestive System

Villi are small, finger-like projections that line the walls of the small intestine. Inside the balls are tiny capillaries called lacteals. By increasing their surface area, the villi maximize the absorption of nutrients.

Any unabsorbed food and nutrients now enter the colon or large intestine. The material is now feces.

As digested food enters the rectum, nerves in the rectal wall known as stretch receptors detect when the chamber is full and stimulate the urge to defecate.

The first happens automatically and cannot be controlled by a person. It is a relaxation of the smooth muscles of the internal anal sphincter.

The Digestive System The Digestive System.

Second, a person can control and consciously relax the skeletal muscles in the external anal sphincter. If a person wants to delay defecation, they can avoid relaxing the muscles to allow stool to move back into the colon.

The longer the stool stays in the colon, the more water the body will absorb. This can cause dry, hard stools, constipation and possibly bruising. For this reason, a person should defecate as soon as it is convenient.

A person should seek medical attention if they are unable to have a bowel movement for about 3 days or if they have abdominal or rectal pain or bleeding.

First, the teeth, tongue, and saliva turn the food into a bolus that is small and liquid enough to pass through the esophagus.

Digestive System Anatomy And Physiology

The bolus then travels to the stomach, where muscle action, acids and enzymes turn it into a paste called chyme. Chime enters the small intestine.

Absorption occurs. Nutrients enter the bloodstream through the capillaries in the villi. From there, the nutrients go to the different cells of the body. Any remaining food goes into the large intestine or large intestine.

The digestive system moves food through the body, breaking it down so nutrients can be absorbed into the bloodstream, where cells can use them for energy, tissue growth and repair, and other purposes.

Digestion involves multiple organs and systems, a series of chemicals, and peristalsis, automatic muscle movements that move food to the next stage.

Digestive System Diagram Images

Anyone who notices a change in their usual digestive processes should seek medical attention, as it could be a sign of a medical condition that needs treatment.

Medical News Today has strict submission guidelines and only uses peer-reviewed studies, academic research institutions, and medical journals and associations. We avoid using tertiary references. We link to primary sources—including research, scholarly references, and statistics—within each article and list them in the resources section at the bottom of our articles. To learn more about how we ensure our content is accurate and up-to-date, read our editorial policy. The function of the digestive system is to break down the food you eat, release its nutrients, and absorb those nutrients into your body. Although the small intestine is the workhorse of the system, where most digestion takes place and where most of the released nutrients are absorbed into the blood or lymph, each organ of the digestive system makes a significant contribution to this process (Figure 23.2). .

23.2. image. Components of the Digestive System All digestive organs play an essential role in the life-sustaining digestion process.

As with all body systems, the digestive system does not work in isolation; it works in cooperation with other body systems. Consider, for example, the interrelationship between the digestive and cardiovascular systems. Arteries supply the digestive organs with oxygen and processed nutrients, and veins drain the digestive tract. These intestinal veins that form the portal system of the liver are unique; they do not return blood directly to the heart. Rather, this blood is diverted to the liver, where its nutrients are loaded for recycling before the blood completes its circuit back to the heart. At the same time, the digestive system provides nutrients to the heart muscle and vascular tissue to support their function. The interrelationship of the digestive and endocrine systems is also important. Hormones secreted by several endocrine glands, as well as endocrine cells of the pancreas, stomach, and small intestine, contribute to the control of digestion and nutrient metabolism. The digestive system, on the other hand, provides nutrients for the functioning of the endocrine system. 23.1. table provides a brief overview of how these other systems contribute to the functioning of the digestive system.

Surprising Parts Of A Ruminant Digestive System

Mucosa-associated lymphoid tissue and other lymphatic tissues protect against pathogen entry; lacteals absorb lipids; and lymphatic vessels transport lipids to the bloodstream

The easiest way to understand the digestive system is to divide its organs into two main categories. The first group is the organs that make up the alimentary canal. The digestive organs comprise the second group and are very important for organizing the breakdown of food and the assimilation of nutrients in the body. The accessory digestive organs, despite their name, are very important to the functioning of the digestive system.

The alimentary canal, also known as the gastrointestinal (GI) tract or intestine, is a one-way tube that is approximately 7.62 meters (25 feet) long during life and closer to 10.67 meters (35 feet). length measured after death when smooth muscle tone has been lost. The main function of the alimentary canal organs is to nourish the body. This tube starts from the mouth and ends at the anus. Between these two points, the canal is transformed into the throat, esophagus, stomach, and small and large intestines to meet the functional needs of the body. Both the mouth and the anus are open to the external environment; thus, food and waste in the alimentary canal are technically considered to be outside the body. Only in the process of absorption do the nutrients in the food enter and nourish the “inner space” of the body.

Each accessory digestive organ assists in the breakdown of food (Figure 23.3). In the oral cavity, the teeth and tongue begin mechanical digestion, while the salivary glands begin chemical digestion. Once food enters the small intestine, the gallbladder, liver, and pancreas release secretions such as bile and enzymes that are essential for digestion to continue. Together, they are called accessory organs because they grow from the lining cells of the developing intestine (mucosa) and reinforce its function; indeed, you could not survive without their important contribution, and many significant diseases result from their malfunction. Even after development is complete, they remain connected to the intestines through ducts.

What Are The Different Parts Of The Digestive Tract? — Colorectal Clinic Of Tampa Bay

Throughout its length, the digestive tract consists of the same four layers of tissue; the details of their structural structure vary to suit their specific functions. Starting from the lumen and moving outward, these layers are the mucosa, submucosa, muscularis, and serosa, which is continuous with the mesentery (see Figure 23.3).

23.3. image. Layers of the alimentary canal The wall of the alimentary canal has four basic tissue layers: mucosa, submucosa, muscularis, and serosa.

Mucous membrane is called mucosa because the production of mucus is a characteristic feature of the intestinal epithelium. The membrane consists of the epithelium, which is in direct contact with ingested food, and the lamina propria, a layer of connective tissue analogous to the dermis. In addition, the mucosa has a thin, smooth muscle layer called the muscularis mucosae (not to be confused with the muscular layer, described below).

— In the mouth, pharynx, esophagus and anal canal, the epithelium is mainly non-keratinized, stratified squamous epithelium. In the stomach and intestines, it is a simple columnar epithelium. Note that the epithelium is in direct contact with the lumen, the space in the alimentary canal. Between its epithelial cells, goblet cells alternate, which secrete mucus and

Gastric Motility: Video, Anatomy, Definition & Function

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