Download Regions of the Digestive System

THE DIGESTIVE SYSTEM
The digestive system includes the digestive tract and its accessory organs, which process food
into molecules that can be absorbed and utilized by the cells of the body. Food is broken down,
bit by bit, until the molecules are small enough to be absorbed and the waste products are
eliminated. The digestive tract, also called the alimentary canal or gastrointestinal (GI) tract,
consists of a long continuous tube that extends from the mouth to the anus. It includes the
mouth, pharynx, oesophagus, stomach, small intestine, and large intestine. The tongue and
teeth are accessory structures located in the mouth. The salivary glands, liver, gallbladder, and
pancreas are major accessory organs that have a role in digestion. These organs secrete fluids
into the digestive tract.
Food undergoes four types of processes in the body:

Ingestion - Take in food through the mouth.

Digestion - Broken into smaller particles that can be acted upon by various enzymes

Absorption - Pass through cell membranes of the lining in the small intestine into the
blood or lymph capillaries.

Elimination - The removal of indigestible wastes through the anus, in the form of
faeces.
Regions of the Digestive System
At its simplest, the digestive system is a tube running from mouth to anus.
Regions of the digestive system can be divided into two main parts: the alimentary tract and
accessory organs. The alimentary tract of the digestive system is composed of the:

Mouth

Pharynx

Oesophagus

Stomach

Small and Large intestines

Rectum and Anus
Associated with the alimentary tract are the following accessory organs:

Salivary Glands



It has a cleansing action on the teeth.

It moistens and lubricates food during mastication and swallowing.

It dissolves certain molecules so that food can be tasted.
Liver


Bile production and excretion

Excretion of bilirubin, cholesterol, hormones, and drugs

Metabolism of fats, proteins, and carbohydrates

Enzyme activation

Storage of glycogen, vitamins, and minerals, and regulation of glucose levels

Synthesis of plasma proteins, such as albumin, and clotting factors

Blood detoxification and purification

Conversion of ammonia, a by-product of metabolism, into a less toxic form
called urea.

Gallbladder - Storage reservoir for bile

Pancreas


Production of Insulin

Production of Pancreatic juices
Common Digestive Problems
Haematemesis is the vomiting of fresh red blood or old darker blood often referred to as coffee
grounds. The source is generally the upper gastrointestinal tract if the blood is fresh or from the
stomach with the darker blood.
Peptic ulcer is a non-malignant ulcer of the stomach (called gastric ulcer) or duodenum (called
duodenal ulcer).
Pancreatitis is an inflammation of the pancreas. It can occur periodically or chronically. The
first sign may be a sudden, severe abdominal pain above the navel, which travels through to the
back. Accompanying symptoms may include a slight fever, nausea, and vomiting.
Constipation is the term given for infrequent or difficult evacuation of small, hard stools,
accompanied by mild abdominal discomfort. When the condition is chronic, it may include
nausea, stomach rumbling, appetite loss, and malaise.