Digestive System

Digestive System

The digestive system consists of the alimentary tract or canal and all the organs and glands associated with the digestion and assimilation of food in animals. Feeding is an important behavior of all living things. Human beings move from one place to another in search of food to eat and to get energy to work. If we eat the food, the digestive organs digest the food into smaller and simpler forms that are useful to our body.

Digestion is the breaking down of large molecules of food into simple and absorbable forms for use by animals. Animals have different types of alimentary tracts that vary in size, complexity, and mode of feeding.

The Process of Getting and Using Food Can Be Shown as a Series of Steps:

Step 1

Ingestion: the taking of complex organic food by the organism.

Step 2

Digestion: the breakdown of large, complex molecules into simpler, soluble ones by enzyme action.

Step 3

Absorption: the uptake of the soluble products of digestion into the main system of the organism, either directly into the cells or into the bloodstream and then the cells.

Step 4

Assimilation: the use of the product of digestion, either as an energy source or to be incorporated into new biological material.

Step 5

Egestion: any undigested food materials are removed from the body by the body's own functioning.

Parts of the Digestive System

• Mouth
• Esophagus
• Stomach
• Duodenum
• Small intestine
• Appendix
• Cecum
• Large intestine
• Rectum
• Anus

Mouth: The alimentary canal of man starts from the mouth. The mouth includes the teeth, tongue, and salivary glands.

Esophagus: Connects the mouth to the stomach. The food swallowed is passed down through the esophagus by a peristalsis movement into the stomach.

Stomach: The food is temporarily stored for about two hours and is released at regular intervals through the opening of the cardiac sphincter. In the stomach, gastric juice containing two enzymes aids in digestion.

Duodenum: The duodenum contains the pancreas, which secretes pancreatic juice that contains three enzymes.

Small Intestine: The small intestine is a long, coiled tube, about 5 - 6m long, with a rich supply of blood and lymph vessels. Two major events take place in the small intestine: digestion and absorption of the digested food.

Cecum and Appendix: They don't have well-known functions, but the cecum usually contains some bacteria that aid in minor digestion.

Large Intestine: Undigested food passes into the large intestine. The absorption of water concentrates the waste products and turns them into feces. The feces are passed into the rectum and finally out of the body through the anus.

Common Digestive System Disorders

• Inflammatory Bowel Disease (IBD)
• Peptic Ulcer Disease (PUD) and Gastritis
• Irritable Bowel Syndrome (IBS)
• Stomach Flu
• Constipation
• Gluten Sensitivity and Celiac Disease
• Hemorrhoids
• Gastroesophageal Reflux Disease (GERD)