digestive system presentation in english

23.1 Overview of the Digestive System

Learning objectives.

By the end of this section, you will be able to:

• Identify the organs of the alimentary canal from proximal to distal, and briefly state their function
• Identify the accessory digestive organs and briefly state their function
• Describe the four fundamental tissue layers of the alimentary canal
• Contrast the contributions of the enteric and autonomic nervous systems to digestive system functioning
• Explain how the peritoneum anchors the digestive organs

The function of the digestive system is to break down the foods you eat, release their nutrients, and absorb those nutrients into the body. Although the small intestine is the workhorse of the system, where the majority of digestion occurs, and where most of the released nutrients are absorbed into the blood or lymph, each of the digestive system organs makes a vital contribution to this process ( Figure 23.2 ).

As is the case with all body systems, the digestive system does not work in isolation; it functions cooperatively with the other systems of the body. 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, constituting the hepatic portal system, are unique; they do not return blood directly to the heart. Rather, this blood is diverted to the liver where its nutrients are off-loaded for processing before 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 functioning. The interrelationship of the digestive and endocrine systems is also critical. Hormones secreted by several endocrine glands, as well as endocrine cells of the pancreas, the stomach, and the small intestine, contribute to the control of digestion and nutrient metabolism. In turn, the digestive system provides the nutrients to fuel endocrine function. Table 23.1 gives a quick glimpse at how these other systems contribute to the functioning of the digestive system.

Digestive System Organs

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. Accessory digestive organs comprise the second group and are critical for orchestrating the breakdown of food and the assimilation of its nutrients into the body. Accessory digestive organs, despite their name, are critical to the function of the digestive system.

Alimentary Canal Organs

Also called the gastrointestinal (GI) tract or gut, the alimentary canal (aliment- = “to nourish”) is a one-way tube about 7.62 meters (25 feet) in length during life and closer to 10.67 meters (35 feet) in length when measured after death, once smooth muscle tone is lost. The main function of the organs of the alimentary canal is to nourish the body. This tube begins at the mouth and terminates at the anus. Between those two points, the canal is modified as the pharynx, esophagus, stomach, and small and large intestines to fit the functional needs of the body. Both the mouth and anus are open to the external environment; thus, food and wastes within the alimentary canal are technically considered to be outside the body. Only through the process of absorption do the nutrients in food enter into and nourish the body’s “inner space.”

Accessory Structures

Each accessory digestive organ aids in the breakdown of food ( Figure 23.3 ). Within the mouth, the teeth and tongue begin mechanical digestion, whereas the salivary glands begin chemical digestion. Once food products enter the small intestine, the gallbladder, liver, and pancreas release secretions—such as bile and enzymes—essential for digestion to continue. Together, these are called accessory organs because they sprout from the lining cells of the developing gut (mucosa) and augment its function; indeed, you could not live without their vital contributions, and many significant diseases result from their malfunction. Even after development is complete, they maintain a connection to the gut by way of ducts.

Histology of the Alimentary Canal

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

The mucosa is referred to as a mucous membrane, because mucus production is a characteristic feature of gut epithelium. The membrane consists of 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 muscularis layer, described below).

Epithelium —In the mouth, pharynx, esophagus, and anal canal, the epithelium is primarily a non-keratinized, stratified squamous epithelium. In the stomach and intestines, it is a simple columnar epithelium. Notice that the epithelium is in direct contact with the lumen, the space inside the alimentary canal. Interspersed among its epithelial cells are goblet cells, which secrete mucus and fluid into the lumen, and enteroendocrine cells, which secrete hormones into the interstitial spaces between cells. Epithelial cells have a very brief lifespan, averaging from only a couple of days (in the mouth) to about a week (in the gut). This process of rapid renewal helps preserve the health of the alimentary canal, despite the wear and tear resulting from continued contact with foodstuffs.

Lamina propria —In addition to loose connective tissue, the lamina propria contains numerous blood and lymphatic vessels that transport nutrients absorbed through the alimentary canal to other parts of the body. The lamina propria also serves an immune function by housing clusters of lymphocytes, making up the mucosa-associated lymphoid tissue (MALT). These lymphocyte clusters are particularly substantial in the distal ileum where they are known as Peyer’s patches. When you consider that the alimentary canal is exposed to foodborne bacteria and other foreign matter, it is not hard to appreciate why the immune system has evolved a means of defending against the pathogens encountered within it.

Muscularis mucosae —This thin layer of smooth muscle is in a constant state of tension, pulling the mucosa of the stomach and small intestine into undulating folds. These folds dramatically increase the surface area available for digestion and absorption.

As its name implies, the submucosa lies immediately beneath the mucosa. A broad layer of dense connective tissue, it connects the overlying mucosa to the underlying muscularis. It includes blood and lymphatic vessels (which transport absorbed nutrients), and a scattering of submucosal glands that release digestive secretions. Additionally, it serves as a conduit for a dense branching network of nerves, the submucosal plexus, which functions as described below.

The third layer of the alimentary canal is the muscularis (also called the muscularis externa). The muscularis in the small intestine is made up of a double layer of smooth muscle: an inner circular layer and an outer longitudinal layer. The contractions of these layers promote mechanical digestion, expose more of the food to digestive chemicals, and move the food along the canal. In the most proximal and distal regions of the alimentary canal, including the mouth, pharynx, anterior part of the esophagus, and external anal sphincter, the muscularis is made up of skeletal muscle, which gives you voluntary control over swallowing and defecation. The basic two-layer structure found in the small intestine is modified in the organs proximal and distal to it. The stomach is equipped for its churning function by the addition of a third layer, the oblique muscle. While the colon has two layers like the small intestine, its longitudinal layer is segregated into three narrow parallel bands, the tenia coli, which make it look like a series of pouches rather than a simple tube.

The serosa is the portion of the alimentary canal superficial to the muscularis. Present only in the region of the alimentary canal within the abdominal cavity, it consists of a layer of visceral peritoneum overlying a layer of loose connective tissue. Instead of serosa, the mouth, pharynx, and esophagus have a dense sheath of collagen fibers called the adventitia. These tissues serve to hold the alimentary canal in place near the ventral surface of the vertebral column.

Nerve Supply

As soon as food enters the mouth, it is detected by receptors that send impulses along the sensory neurons of cranial nerves. Without these nerves, not only would your food be without taste, but you would also be unable to feel either the food or the structures of your mouth, and you would be unable to avoid biting yourself as you chew, an action enabled by the motor branches of cranial nerves.

Intrinsic innervation of much of the alimentary canal is provided by the enteric nervous system, which runs from the esophagus to the anus, and contains approximately 100 million motor, sensory, and interneurons (unique to this system compared to all other parts of the peripheral nervous system). These enteric neurons are grouped into two plexuses. The myenteric plexus (plexus of Auerbach) lies in the muscularis layer of the alimentary canal and is responsible for motility , especially the rhythm and force of the contractions of the muscularis. The submucosal plexus (plexus of Meissner) lies in the submucosal layer and is responsible for regulating digestive secretions and reacting to the presence of food (see Figure 23.3 ).

Extrinsic innervations of the alimentary canal are provided by the autonomic nervous system, which includes both sympathetic and parasympathetic nerves. In general, sympathetic activation (the fight-or-flight response) restricts the activity of enteric neurons, thereby decreasing GI secretion and motility. In contrast, parasympathetic activation (the rest-and-digest response) increases GI secretion and motility by stimulating neurons of the enteric nervous system.

Blood Supply

The blood vessels serving the digestive system have two functions. They transport the protein and carbohydrate nutrients absorbed by mucosal cells after food is digested in the lumen. Lipids are absorbed via lacteals, tiny structures of the lymphatic system. The blood vessels’ second function is to supply the organs of the alimentary canal with the nutrients and oxygen needed to drive their cellular processes.

Specifically, the more anterior parts of the alimentary canal are supplied with blood by arteries branching off the aortic arch and thoracic aorta. Below this point, the alimentary canal is supplied with blood by arteries branching from the abdominal aorta. The celiac trunk services the liver, stomach, and duodenum, whereas the superior and inferior mesenteric arteries supply blood to the remaining small and large intestines.

The veins that collect nutrient-rich blood from the small intestine (where most absorption occurs) empty into the hepatic portal system. This venous network takes the blood into the liver where the nutrients are either processed or stored for later use. Only then does the blood drained from the alimentary canal viscera circulate back to the heart. To appreciate just how demanding the digestive process is on the cardiovascular system, consider that while you are “resting and digesting,” about one-fourth of the blood pumped with each heartbeat enters arteries serving the intestines.

The Peritoneum

The digestive organs within the abdominal cavity are held in place by the peritoneum, a broad serous membranous sac made up of squamous epithelial tissue surrounded by connective tissue. It is composed of two different regions: the parietal peritoneum, which lines the abdominal wall, and the visceral peritoneum, which envelopes the abdominal organs ( Figure 23.4 ). The peritoneal cavity is the space bounded by the visceral and parietal peritoneal surfaces. A few milliliters of watery fluid act as a lubricant to minimize friction between the serosal surfaces of the peritoneum.

Disorders of the...

Digestive system: peritonitis.

Inflammation of the peritoneum is called peritonitis. Chemical peritonitis can develop any time the wall of the alimentary canal is breached, allowing the contents of the lumen entry into the peritoneal cavity. For example, when an ulcer perforates the stomach wall, gastric juices spill into the peritoneal cavity. Hemorrhagic peritonitis occurs after a ruptured tubal pregnancy or traumatic injury to the liver or spleen fills the peritoneal cavity with blood. Even more severe peritonitis is associated with bacterial infections seen with appendicitis, colonic diverticulitis, and pelvic inflammatory disease (infection of uterine tubes, usually by sexually transmitted bacteria). Peritonitis is life threatening and often results in emergency surgery to correct the underlying problem and intensive antibiotic therapy. When your great grandparents and even your parents were young, the mortality from peritonitis was high. Aggressive surgery, improvements in anesthesia safety, the advance of critical care expertise, and antibiotics have greatly improved the mortality rate from this condition. Even so, the mortality rate still ranges from 30 to 40 percent.

The visceral peritoneum includes multiple large folds that envelope various abdominal organs, holding them to the dorsal surface of the body wall. Within these folds are blood vessels, lymphatic vessels, and nerves that innervate the organs with which they are in contact, supplying their adjacent organs. The five major peritoneal folds are described in Table 23.2 . Note that during fetal development, certain digestive structures, including the first portion of the small intestine (called the duodenum), the pancreas, and portions of the large intestine (the ascending and descending colon, and the rectum) remain completely or partially posterior to the peritoneum. Thus, the location of these organs is described as retroperitoneal .

Interactive Link

By clicking on this link you can watch a short video of what happens to the food you eat, as it passes from your mouth to your intestine. Along the way, note how the food changes consistency and form. How does this change in consistency facilitate your gaining nutrients from food?

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Access for free at https://openstax.org/books/anatomy-and-physiology-2e/pages/1-introduction

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The Digestive System in 17 PowerPoint Templates [Free PDF Attached]

Lakshya Khurana

‘Energy and Food,’ so goes the title of a chapter in a Grade-5 textbook. Amidst the pictures of wonderful foods, the lesson plan's key aim was hidden. This was to help us become familiar with our digestive system. Cut to today, and millions of us, including top-notch business executives, will struggle to remember anything of consequence about the digestive system.

This blog will take you through those times and the route our food takes from the time we put it into our mouths.

First things first, however. It is the digestive system's job to ensure nutrients in the food we consume to get to where they are needed and in the form that they can be used; burning food to create energy is the most simple explanation.

The digestive system starts working as soon as you take that first bite and keeps on working as the food makes its way down to be broken down into forms that are palatable by your cells. What is not needed is removed from the body.

This blog offers 17 informative PowerPoint Templates to give you the best presentation on this vital human organ system.

This collection is relevant for any age group and for all segments of the population  because the templates are:

• CONTENT-READY: You do not need to conduct any research; we have curated that for you.
• EDITABLE: Any information that catches your attention can be added to or deleted from these slides.

Each deck has several slides presenting the diagram with and without the labels and highlighting individual parts, making for an educational presentation experience for everyone!

Template 1: Human Stomach Anatomy PowerPoint Slides

The human stomach is an amazing piece! With this PPT Deck, you'll be able to illustrate the parts and functions of the stomach in a clear and concise way. The images are color-coordinated to improve retention among the audience. Download this presentation template now.

Download this template

Template 2: Human Stomach Anatomy (Musculature) PPT Slides

This PowerPoint Set features detailed and labeled illustrations of the stomach and other important organs in the digestive system. It showcases the layers of the stomach that help it perform its functions. Get it now to present this important organ (which is also a part of the immune system).

Grab this template

Template 3: Human Stomach Anatomy (Layered) PowerPoint Layout

The human stomach is connected to the rest of the digestive system. With this presentation template collection, you'll have everything you need to create an engaging presentation in the method of cross-sections. Employ it now to be perceived as a master educator!

Template 4: Biliary System PPT Deck

These PowerPoint Slides provide a wealth of information on the structure and function of the Biliary System. They are packed with illustrations that help bring the concepts to life. This presentation template covers the key information about the biliary system, including its anatomy and physiology. Employ it now.

Template 5: Biliary System Within The Digestive System

This PPT Theme presents the Biliary System and how it fits with the rest of the digestive system. The illustrations are clear and easy to follow, making this an ideal resource. Get this presentation template right away!

Template 6: Pancreas and Gallbladder PPT Theme

If you're looking for a way to spice up your next presentation on the human digestive system, look no further than our Pancreas and Gallbladder PowerPoint slides! These make for the juices in the stomach. Download it now to educate the audience.

Template 7: Internal Anatomy of Liver PowerPoint Preset

The internal anatomy of the liver is a fascinating subject, and these PPT slides provide a detailed and intriguing look at this organ. These slides are perfect for anyone interested in learning about the internal anatomy of the liver, our storage house for sweetness. Download them now.

Template 8: External Anatomy of Liver PPT Set

As one of the most important organs in the body, the liver plays a vital role in digestion. Interestingly, the liver is also one of the few organs that can regenerate itself. Educate your audience on this amazing organ by downloading this PowerPoint Theme.

Template 9: Liver Cross-Section PowerPoint Bundle

The liver is a vital organ that plays a crucial role in the human body. It is responsible for filtering blood, producing bile, and storing nutrients. It is also a powerhouse of antioxidants and helps to protect the body from harmful toxins. Download this PPT Preset now.

Template 10: Large and Small Intestine PPT Deck

The large and small intestines are two important organs, working together to digest food and absorb nutrients. The PowerPoint Slides provide detailed, labeled images of the internal anatomy of the intestines and helps an audience understand its structure and function. Download this PPT bundle now.

Template 11: Anatomy of Large Intestine PPT Theme

The large intestine is a remarkable organ that plays a crucial role in our health and well-being. Our PowerPoint Slides provide detailed information on parts of the large intestine. Get it now.

Template 12: Large Intestine PowerPoint Preset

If you're looking for an in-depth, informative PowerPoint Presentation on the large intestine, look no further! Our large intestine PowerPoint Slides provide a comprehensive overview of this vital organ, complete with colorful illustrations and detailed information. Download it now to master an academic topic of substantial value.

Template 13: Duodenum Anatomy PPT Slides

The duodenum is the first and shortest part of the small intestine. It has many functions, including breaking down food with digestive enzymes, absorbing nutrients from food, and secreting hormones that regulate digestion. Get this PowerPoint Theme now, and showcase how tiny can be BIG in digestion.

Template 14: Small Intestine Anatomy Slides

The small intestine PowerPoint Slides are packed with information about the small intestine, including its function, structure, and how it aids in digestion. Order your small intestine PPT Deck today and take your presentations to the next level!

Template 15: Small Intestine Slides

The small intestine PowerPoint Bundle is the perfect way to learn about the human digestive system! This helpful resource provides detailed information and illustrations about the small intestine, including its function, structure, and clinical significance. Employ it now.

Template 16: Rectum PPT Deck

The rectum is like the automatic waste collector of the body. With these PPT Slides, you'll be able to teach your audience about the rectum in a way that is both engaging and informative. Download it now.

Template 17: Digestive Arteries and Celiac Trunk PPT Deck

The digestive arteries help improve circulation and oxygenation in the digestive tract, leading to better overall digestion and absorption of nutrients. The celiac trunk can help keep the digestive system functioning well. The PowerPoint Slides are easy to edit and customize, so you can make them your own. Download them now.

Bottom Line

The digestive system is an incredibly complex biological machinery that is much more than the sum of its parts. In physical appearance, parts that range from the microscopic to a few feet long! There is much left to be discovered about how our body interacts with nutrition but what we do know is amazing.

The Digestive System: A Refresher

Let’s go through a quick rundown of the digestive system!

The digestive system is responsible for breaking down food and turning it into energy that the body can use. The digestive system includes the mouth, esophagus, stomach, intestines, and anus.

The mouth is the first part of the digestive system. The teeth break down food into small pieces. The tongue mixes food with saliva, which contains enzymes that begin to break down food.

The esophagus is a tube that carries food from the mouth to the stomach. The stomach is a sac that stores food and mixes it with acids and enzymes that continue to break down food.

The small intestine is a long, coiled tube where most food digestion and absorption occur. The large intestine is a shorter tube that absorbs water and vitamins from the food that has not been digested. The rectum and anus are the last part of the digestive system. Waste material is stored in the rectum until it is passed through the anus as feces.

FAQs on The Digestive System

Which actions help keep your digestive system healthy?

There are a few key things you can do to keep your digestive system healthy and functioning properly. First, eat a healthy diet that includes plenty of fiber. This will help keep things moving along smoothly and prevent constipation. Second, stay hydrated by drinking plenty of water. This will also help keep things moving smoothly and prevent constipation. Third, exercise regularly. This helps to keep everything moving and prevents stagnation. Finally, pay attention to your body and listen to what it tells you. If you have any problems, such as pain, diarrhea, or constipation, be sure to see a doctor to rule out any serious underlying conditions.

How does the digestive system maintain homeostasis?

The digestive system is responsible for maintaining homeostasis in the body by breaking down food into nutrients that can be used by the cells and eliminating waste products from the body. This is a critical function without which we cannot function to the best of our ability. After all, the human body is a machine, though it speaks and moves on its own.

What are the three main jobs of the digestive system?

The digestive system is responsible for three main jobs: breaking down food, absorbing nutrients, and eliminating waste.

• Breaking down food: The digestive system breaks down food into smaller pieces so that the body can absorb them. This process begins in the mouth.
• Absorbing nutrients: The digestive system absorbs nutrients from food so that the body can use them. Nutrients are absorbed through the walls of the small intestine into the bloodstream and then circulated throughout the body.
• Eliminating waste: The digestive system eliminates waste from the body through feces. Feces are stored in the large intestine until they are ready to be eliminated through the rectum and anus.

What are the five steps of digestion?

The five steps of digestion are as follows:

• Ingestion: This is the first step in the digestive process, during which food is taken into the mouth and begins to be broken down by saliva.
• Propulsion: This second step involves moving the food through the rest of the digestive system via muscular contractions.
• Digestion: Food is further broken down by the stomach and small intestine enzymes during this third step.
• Absorption: In the fourth step of digestion, nutrients are absorbed from the food into the bloodstream through the walls of the small intestine.
• Defecation: The fifth and final step of digestion is the elimination of solid waste from the body through the process of defecation.

Download the free Digestive System PDF .

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• Biology Article

Human Digestive System

Digestive system of humans.

The digestive tract of humans starts with the mouth and ends with the anus. It includes different structures such as the mouth, oesophagus, pancreas, stomach, small intestine, large intestine, liver, gall bladder, and anus.

Table of Contents

Introduction Structure Parts

• Small Intestine

Large Intestine

Accessory organs, digestion process.

• Mixing and Movement

Disorders Functions  Notes

The Human Digestive System

The digestive system of the human body comprises a group of organs working together to convert food into energy for the body. Anatomically, the digestive system is made up of the gastrointestinal tract, along with accessory organs such as the liver, pancreas and gallbladder. The hollow organs that make up the gastrointestinal tract (GI tract) include the mouth, stomach, oesophagus, small intestine and large intestine that contains the rectum and anus.

Human Digestive System and Nutrition involve the intake of food by an organism and its utilization for energy. This is a vital process which helps living beings to obtain their energy from various sources. The food which we eat undergoes much processing before the nutrients present in them are utilized to generate energy. This processing is known as digestion. Humans and other animals have specialized organs and systems for this process.

The digestion process involves the alimentary canal along with various accessory organs and organ systems. In humans, the process is quite simple due to our monogastric nature. This means that we have a one-chambered stomach, unlike other animals such as cows, which have four chambers.

Some parts of nervous and circulatory systems also play a significant role in the digestion process. A combination of nerves, bacteria, hormones, blood and other organs of the digestive system completes the task of digestion.

Let us have a detailed look at the human digestive system, its parts and functions. Also provided at the end of the chapter are digestive system notes.

Also Read:  Alimentary Canal

Diagram Of The Human Digestive System

The diagram given below represents different parts of the human digestive system that convert food into essential nutrients absorbed by the body.

Parts of the Human Digestive System

The digestive system of the human body comprises a group of organs that work together in converting food into energy and other basic nutrients to power the body. The food we take in is digested and utilized by our body, and the unused parts of the food are defecated.

The digestive system of the human body is the sum of the gastrointestinal tract (GIT; also called alimentary canal) and accessory organs (tongue, liver, pancreas, etc.). These two parts together help in the digestion process.

The alimentary canal is the long tube through which the food that we eat is passed. It begins at the mouth (buccal or oral cavity), passes through the pharynx, oesophagus or food pipe, stomach, small intestines, large intestines, rectum and finally ends at the anus. The food particles gradually get digested as they travel through various compartments of the alimentary canal.

Accessory organs are organs which participate in the digestion process but are not actually a part of GIT. They stimulate the digestion by releasing certain enzymes that help in breaking down the food.

Let us have a detailed look at the digestive system of the human body, along with its parts and functions:

Food starts its journey from the mouth or the oral cavity. There are many other organs that contribute to the digestion process, including teeth, salivary glands, and tongue. Teeth are designed for grinding food particles into small pieces and are moistened with saliva before the tongue pushes the food into the pharynx.

A fibromuscular y-shaped tube attached to the terminal end of the mouth. It is mainly involved in the passage of chewed/crushed food from the mouth through the oesophagus. It also has a major part in the respiratory system, as air travels through the pharynx from the nasal cavity on its way to the lungs.

This is a muscular tube that connects the pharynx, which is a part of an upper section of the gastrointestinal tract. It supplies swallowed food along with its length.

Also Read:  Food Pipe

It serves as a muscular bag which is situated towards the left side of the abdominal cavity, beneath the diaphragm. This vital organ acts as a storage for the food and provides enough time to digest meals. The stomach also produces digestive enzymes and hydrochloric acid that maintains the process of digestion.

Mucous : It is an aqueous secretion produced by the mucous membranes. It functions by protecting the stomach lining and gastric pits from the acid, which is produced by the glands to destroy the bacteria that entered along with the food particles.

Digestive enzymes : They are the group of enzymes which functions by breaking down polymeric macromolecules like biopolymers into their smaller and simpler substances.

Hydrochloric acid : It is the digestive fluid formed by the stomach during the process of digestion. It functions by destroying harmful microorganisms present in the food particles.

The small intestine is a thin, long tube of about 10 feet long and a part of the lower gastrointestinal tract. It is present just behind the stomach and acquires a maximum area of the abdominal cavity. The complete small intestine is coiled and the inner surface consists of folds and ridges.

This is a thick, long tube measuring around 5 feet in length. It is present just beneath the stomach and wraps over the superior and lateral edges of the small intestine. It absorbs water and consists of bacteria (symbiotic) that support the breakdown of wastes to fetch small nutrients.

Also Read:  Large Intestine

Waste products are passed into the end of the large intestine called the rectum and eliminated out of the body as a solid matter called stool. It is stored in the rectum as semi-solid faeces which later exits from the body through the anal canal through the process of defecation.

It is a large gland present just behind the stomach. It is short with its anterior connected to the duodenum and posterior pointing towards the left part of the abdominal cavity. The pancreas releases digestive enzymes to complete the process of chemical digestion.

Read More:  Pancreas

The liver is a roughly triangular, reddish-brown accessory organ of the digestive system located to the right of the stomach. It produces bile , which helps in the digestion of fat in the small intestine. The bile is stored and recycled in the gallbladder. It is a small, pear-shaped organ which is located just next to the liver.

Also Read:  Cellulose in Digestion

The process of digestion begins from the mouth and ends in the small intestine – the large intestines’ main function is to absorb the remaining water from the undigested food and enable bacterial fermentation of materials that can no longer be digested.

The alimentary canal or the gastrointestinal tract is a series of hollow organs and tubes that begins from the mouth cavity and continues into the pharynx, through the stomach, small intestines, large intestines, and finally ending at the anus. Food particles gradually get digested as they travel through various compartments of the gastrointestinal tract.

The digestion process takes place in the following steps.

The very first step involves mastication (chewing). The salivary glands, along with the tongue, helps to moisten and lubricate food, before being pushed down into the food pipe.

It involves the process of lubricating and manipulating food and pushing it down the food through the food pipe (using peristalsis ), and into the stomach.

The stomach, small intestine, liver, and pancreas secrete enzymes and acids to aid the process of digestion. It functions by breaking down food particles into simple components and easily absorbable components.

Also Read:  What is Liver

The process of converting complex food particles into simpler substances in the presence of enzymes and acids secreted by different digestive organs.

Read more: What are digestive juices?

This process begins in the small intestine where most of the nutrients and minerals are absorbed. The excess water in the indigestible matter is absorbed by the large intestines.

The process of removing indigestible substances and waste by-products from the body through the process of defecation.

In a nutshell, the digestion process consists of the six following steps:

Ingestion  ⇒ Mixing and Movement  ⇒  Secretion  ⇒  Digestion  ⇒ Absorption  ⇒ Excretion

Also Read:  Gastrointestinal Tract

Disorders of the Human Digestive System

Vomiting : It is the ejection of stomach contents through the mouth.

Diarrhoea : It is the abnormal watery bowel movement. Prolonged diarrhoea eventually leads to dehydration.

Constipation : A condition in which the faeces are clutched within the rectum due to an irregular bowel movement.

Indigestion : A pain or discomfort in the stomach which is caused when food is not digested properly, resulting in the feeling of fullness.  Indigestion is mainly caused due to inadequate enzyme secretion, food poisoning, anxiety, overeating and eating spicy foods.

Also Read:  Difference between trachea and oesophagus

Functions of the Human Digestive System

Digestion and absorption are the two main functions of the digestive system.

Digestion is necessary for breaking down food particles into nutrients that are used by the body as an energy source, cell repair and growth.

Food and drink need to be converted into smaller molecules of nutrients before it is absorbed by the blood and carried to the cells throughout the body. The body breaks the nutrients present in the drinks and food into carbohydrates, vitamins, fats and proteins.

Human Digestive System Notes

• The human digestive system breaks down food to release energy essential for the body to carry out its activities.
• The process of digestion takes place in 6 major steps.
• The food is ingested by the alimentary canal and is propelled through the body for further processing.
• The autonomous nervous system controls the peristalsis, contraction and relaxation of muscles within the alimentary canal wall.
• The food is passed to the small intestine where it is digested, and the nutrients are absorbed.
• Water, electrolytes and vitamins are absorbed by the large intestine and the waste is defecated.

Also Read:  Mouth and Buccal Cavity

To learn more about the human digestive system parts and functions, as well as related topics such as the digestion process and disorders of the digestive system, keep visiting  BYJU’S Biology or download the BYJU’S app, for further reference.

Frequently Asked Questions

Deduce the function of the human digestive system..

The digestive system consists of the alimentary canal and the accessory organs. Their main function is to break down the ingested food into its components and produce vital nutrients and energy required to sustain life.

What are accessory organs?

Accessory organs are organs which are not part of the digestive system; however, they aid in the digestion process by performing many secondary functions. The main accessory organs of the digestive system are the tongue, liver, pancreas and gall bladder.

Outline the process of digestion, step by step.

The process of digestion involves the following steps, namely:

List out the parts of the digestive system.

• Mouth & Buccal Cavity

Explain the role of the tongue as an accessory organ.

The tongue is not a part of the digestive system, but it provides support functions such as moving and manipulating the food within the buccal cavity. Furthermore, moistening food also helps to swallow and pass through the oesophagus without much resistance.

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Put your understanding of this concept to test by answering a few MCQs. Click ‘Start Quiz’ to begin!

Select the correct answer and click on the “Finish” button Check your score and answers at the end of the quiz

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The Digestive System

This resource provides a lesson about digestion in humans, linked to curriculum objectives. It is structured around a series of captivating, educational films. The films highlight the structure and function of the key organs of the digestive system, focusing on what happens at each stage on food's incredible journey. The detailed lesson plan includes key teaching points, activities, misconceptions and questions to check understanding. This resource has been provided by Tigtag  primary science resources.

You may also be interested in our online, self-paced course  Teaching primary science: body processes.  

Food's Incredible Journey

The Intestines  

Odd One Out

True of False

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Digestive System Case Study

Digestive system case study presentation, free google slides theme and powerpoint template.

Download the "Digestive System Case Study" presentation for PowerPoint or Google Slides. A clinical case is more than just a set of symptoms and a diagnosis. It is a unique story of a patient, their experiences, and their journey towards healing. Each case is an opportunity for healthcare professionals to exercise their expertise and empathy to help those in need. With this editable template for Google Slides or PowerPoint, you can describe a clinical case in detail, something that might be invaluable for medical students and fellow doctors.

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• Contains easy-to-edit graphics such as graphs, maps, tables, timelines and mockups
• Includes 500+ icons and Flaticon’s extension for customizing your slides
• Designed to be used in Google Slides and Microsoft PowerPoint
• Includes information about fonts, colors, and credits of the resources used

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LESSON PLAN FOR ENGLISH TEACHERS

The digestive system.

Level: Intermediate (B1-B2)

Type of English: Medical English

Tags: health and wellbeing medicine, biology and health food and drink pronouns quantifiers (a lot, much, a little/few, etc.) 18+ years old 16-18 years old Article based

Publication date: 04/09/2022

This lesson will focus on the digestive process and conditions that are related to digestion. The listening will look at the problem of lactose intolerance while the reading comprehension discusses the issue of gluten intolerance. Grammar will focus on quantifiers.

by Patrice Crysler

the digestive system_bre.mp3

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Student worksheet

Teacher lesson plan

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the digestive system_ae.mp3

COURSE PLANS

This comprehensive course plan covers the full range of language needs – listening, role play, vocabulary development.

Worksheets in Medical English course plan

Type of English: Medical English Level: Intermediate (B1-B2)

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