The systems of the body are, for some of us, but a vague memory from science class or maybe home-economics. Do those classes still exist? Anyway today we’re going to get back to basics and discuss the ins and outs of the digestive system, without you having to dig out that old textbook.
What is the Digestive System?
The digestive system starts at the mouth and ends at the anus. the main feature being the gastrointestinal tract (GI tract) a long tube going from one end to the other, with a bunch of hollow organs connected to it; mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus. The solid organs of the digestive system are the liver, pancreas and gallbladder—these are also known as the accessory digestive glands. Parts of the digestive process works in tandem with the nervous, circulatory and excretory systems.
How Does it Work?
The digestive process moves food through the GI tract. Digestion starts in the mouth and ends in the small intestine, food is broken down via mechanical and chemical means as it works its way through the body. As it passes, food mixes with digestive juices which causes large molecules to be broken down into smaller molecules which are then absorbed through the wall of the small intestine and into the bloodstream. The bloodstream delivers these molecules to the rest of the body.
- Mouth chews food and breaks down starch with help from the salivary glands.
- Esophagus carries food from the mouth to the stomach.
- Food mixes with stomach acid which breaks down protein.
- The small intestine does the most work, absorbing nutrients and breaking down proteins, starches and carbohydrates.
- The pancreas breaks down starches, fats and proteins.
- The liver breaks down fats.
What Happens to the Food?
The small intestine absorbs most of the food molecules by far, specialised cells absorb nutrients and pass on what is necessary to other parts of the body. The bloodstream carries simple sugars, amino acids, salts, vitamins and glycerol to the liver. The lymphatic system helps absorb fatty acids and vitamins, along with carrying white blood cells around the body. Once everything is absorbed it passes through the large intestine and exits the body as stool.
How is it Controlled?
The digestive process is controlled by hormone and nerve regulators. The stomach and small intestine have cells that produce and release hormones that stimulate the production of digestive juices and help regulate appetite. Extrinsic and intrinsic nerves control the actions of the digestive system.
The extrinsic nerves release chemicals that cause the muscle layer of the GI tract to either contract or relax, depending on whether food needs digesting. The intrinsic nerves kick into gear when food stretches the lining of the hollow organs. They release substances that either speed up or delay the movement of food and the production of digestive juices.
What Digestive Conditions and Illnesses are Common?
If there are irregularities within the digestive system, a number of conditions can occur,
- Crohn’s disease
- Coeliac disease - see also: 7 Ways Gluten is Ruining Your Life
- Jaundice
- Gastroenteritis
- Appendicitis
- Irritable Bowel Syndrome (IBS)
- Haemorrhoids
If you are worried about issues with your digestive tract, please make sure to contact a health care professional, the NHS are there to help.
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Editors Note: Here at The Nopebook we want to help you to understand your body, what is supposed to be going on, and what could be going wrong - but we are not health professionals or doctors. The above is for information only, to give you a better understanding, and does not replace a trip to the doctors.
