Digestive How It Works

Digestive System Overview

The digestive system is a group of organs that work together to convert food into energy and basic nutrients to feed the entire body. The process of digestion begins in the mouth and continues in the esophagus, stomach, small intestine, and large intestine. Additional organs that aid in digestion include the liver, pancreas, and gallbladder.

Mouth and Esophagus

Chewing food in the mouth breaks it down into smaller pieces, increasing the surface area for enzymes to work. Saliva contains an enzyme called amylase that begins to break down carbohydrates. The tongue moves food around the mouth and pushes it into the back of the throat, triggering a swallow. The epiglottis closes over the trachea to prevent food from entering the lungs. The food passes through the esophagus, a muscular tube that connects the mouth to the stomach. Muscles in the esophagus contract and relax in a wave-like motion called peristalsis, which pushes food downward.

Stomach

The stomach is a J-shaped organ that further breaks down food and begins the process of extracting nutrients. The stomach secretes gastric juices, which contain hydrochloric acid and an enzyme called pepsin, which begins to break down proteins. The powerful muscles in the stomach churn and mix food, forming a semi-liquid substance called chyme.

Small Intestine

The small intestine is a long, coiled tube where most nutrients are absorbed. The walls of the small intestine are lined with villi, small finger-like projections that increase the surface area for absorption. Here, the pancreas secretes enzymes that break down carbohydrates, proteins, and fats. The liver produces bile, which helps in the digestion of fats. The small intestine also absorbs vitamins, minerals, and water.

Large intestine and Rectum

Undigested material passes into the large intestine, also known as the colon. The main function of the large intestine is to absorb water and electrolytes from waste and form stool. Beneficial bacteria in the large intestine help break down certain types of carbohydrates, producing gases like methane and hydrogen. The rectum is the final portion of the large intestine where stool is stored until it is passed out of the body through the anus.

The digestive system is essential for the body to obtain energy from food and maintain overall health. Proper functioning of each organ and the coordinated actions of enzymes, hormones, and muscles are necessary for the efficient digestion of food and absorption of nutrients.