How does the digestive system work?

The digestive system is a complex network of organs working together to break down food and absorb nutrients. It starts in the mouth, where chewing and saliva begin the process of mechanical and chemical digestion. Enzymes in saliva initiate the breakdown of carbohydrates. The chewed food, now called bolus, travels down the esophagus and into the stomach.

In the stomach, gastric juices containing acids and enzymes continue breaking down the food into a semi-liquid substance called chyme. The stomach's muscular walls churn and mix the contents, aiding in digestion. From the stomach, the chyme moves into the small intestine, where most nutrient absorption takes place. The pancreas and liver contribute digestive enzymes and bile to further break down fats, proteins, and carbohydrates. The small intestine's walls are lined with tiny structures called villi and microvilli, increasing the surface area for nutrient absorption.

The remaining indigestible material moves into the large intestine, where water and electrolytes are absorbed, forming feces. Bacteria in the colon also play a role in breaking down certain substances. Finally, the rectum stores feces until they are ready to be expelled through the anus. The digestive process is regulated by a combination of nervous and hormonal signals, ensuring the body receives the necessary nutrients while efficiently eliminating waste.