What is the Digestive System?

The human digestive system digests food, absorbs nutrients, and then excretes waste products as poop. It consists of five parts: mouth, pharynx, oesophagus, stomach, small intestine, and large intestine. Accessory organs include the teeth, the tongue, the salivary glands, the liver, the gallbladder, and the pancreas.3

What Does the Digestive System do?

Our digestive system’s job is simple and fundamental: converting food into energy for our survival.4 When we eat an apple, for example, it goes through three different body processes: digestion, absorption, and defecation. And all good things come in threes, right?

The Anatomy of the Digestive System

Several organs and body parts work together like clockwork, each one a part of a well-oiled machine needed to keep the digestive system running smoothly. Let's get to know them.

Ilustración: The Digestive System (NIH NIDDK, 2017 3)

Ilustration: The Digestive System (NIH NIDDK, 2017 3)

1. Oral cavity

Digestion starts in the mouth with the mechanical processing of the food by the teeth and tongue. Tasting what we eat, and lubrication of food (so we can swallow it!) also takes place here.3

2. Pharynx

The pharynx is a passageway that transports food materials to the oesophagus. Common names for it include the gullet, or food pipe.3,6

3. Oesophagus

Through waves of muscular contractions, the oesophagus is primarily responsible for carrying food materials into the stomach.3

4. Stomach

In the stomach, food is mechanically and chemically broken down. Muscular contractions and relaxations of the stomach lead to the formation of chyme, which is a mixture of partially digested food particles in a liquid state. Food is then broken down by gastric juices.3

5. Small intestine

90% of nutrients are absorbed in the small intestine. During digestion, the small intestine receives chyme from the stomach and digestive material from the pancreas and liver. The small intestine is the primary site of chemical digestion and absorption.3

6. Large instestine

The large intestine is responsible for absorbing water, vitamins, and salts.25 It then moves faeces into the rectum through waves of muscle contractions. In the rectum, receptors initiate the pooping process, which concludes at the anus.3

The Digestive Process

Six actions take place in the digestive system before the body can use nutrients.6

1. Ingestion

The digestive process begins with everyone’s favourite pastime; eating! 6

2. Mechanical Digestion

Food pieces must be broken down into smaller pieces for digestion. Mechanical digestion begins in the mouth, with the teeth and tongue, followed by churning and mixing in the stomach.6

3. Chemical Digestion

Chemical digestion breaks down carbohydrates, proteins, and fats into smaller molecules that can be absorbed for use in the body.6

4. Movements

In the stomach, smooth muscle contractions combine food particles with enzymes and other fluids. Further waves of muscle contractions in the intestines also move food particles through the digestive tract.6

5. Absorption

During absorption, nutrients enter the blood vessels through the lining of the small and large intestine. The blood can then transport the nutrients around the body to where they are needed. 6

6. Elimination

The body eliminates food molecules that cannot be digested or absorbed. This final little process is better known as pooping. 6

Frequently Asked Questions

  • Gastrointestinal (GI) tract organs have a layer of muscle that allows their walls to move. This movement, called peristalsis, can be compared to an ocean wave moving through a muscle.7 As a result, food and liquid are mixed and pushed through the GI tract.8

  • As food moves through your digestive tract, it is broken down into smaller pieces through motion (chewing and squeezing) and the mixing of digestive juices. These juices include stomach acid, bile, and enzymes.8

  • In the small intestine, digested food molecules, water, and other nutrients are absorbed. Most materials enter the bloodstream upon absorption. Here, they are transported to other body parts for storage or chemical modification. The sugars, amino acids, fatty acids, and glycerol in these substances allow your body to produce energy, grow, and repair cells.8

What are Common Conditions Related to the Digestive System?

As much as it should run like a well-oiled machine, and usually does, sometimes the digestive system does encounter problems. Don’t we all?

About one in six hospital admissions are for a primary gastrointestinal disease and about one in six of the main surgical procedures in general hospitals are performed on the digestive tract.11

Here are a few conditions that can affect the digestive system.

When to Contact Medical Professionals About Digestive Issues

Improving your intestinal health requires action, but the results are well worth it. The benefits of treating constipation, for example, extend to all aspects of life. You feel ready to face a new day after a good morning poop.

If dietary and lifestyle adjustments don’t help, you can try laxatives.

The Dulco Range

A full range of Dulcolax products is available here, including tablets and suppositories.

Consult your GP if you experience symptoms like constipation, diarrhoea, vomiting, stomach cramps, excessive gas, or heartburn on a regular basis.

Taking care of your digestive system is taking care of yourself, so don’t neglect it, listen closely to the hum and whir of something not feeling right, and do what you need to make sure your digestive system keeps on and carries on running smoothly.

MAT-XU-2304716 (v1.0) November 2023  

Learn more about constipation

Here, you'll find answers to some of the most common questions about constipation. We offer guidance on how to get rid of constipation and how to stay regular.

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