The digestive system, comprised of the digestive tract and accessory organs, breaks down food into smaller molecules for absorption and utilization by the body. The digestive tract includes the mouth, esophagus, stomach, small intestine, large intestine (colon), rectum, and anus, all lined with mucosa containing digestive juices-producing glands. Smooth muscles within these organs aid in food breakdown and movement.
Accessory organs like the liver, pancreas, and gallbladder produce digestive juices that aid in digestion. The liver’s juices are stored in the gallbladder and released into the intestine when needed. Additionally, the nervous and circulatory systems play significant roles in digestion.
Digestion is crucial because it converts food into smaller molecules for absorption into the bloodstream to nourish cells and provide energy.
Digestion begins in the mouth through chewing and swallowing, with the process completed in the small intestine. Food movement through the system is facilitated by muscle contractions, known as peristalsis, which push food and fluids along the digestive tract. Swallowing initiates the first major muscle movement, with the lower esophageal sphincter relaxing to allow food passage into the stomach.
The stomach has three primary tasks: storing swallowed material, mixing it with digestive juices, and slowly emptying it into the small intestine. Factors such as food type and muscle action influence stomach emptying.