رحلة الطعام في الجهاز الهضمي: كيف يعمل؟

Let's explore the first stage of digestion - the journey from mouth to stomach.The digestive journey begins in the mouth, where food is mechanically broken down by the teeth.The tongue helps move food around while salivary glands release digestive enzymes.These enzymes begin breaking down carbohydrates, starting the chemical digestion process.The chewed food mixes with saliva to form a soft mass called a bolus.The tongue then pushes the food bolus into the pharynx.From there, the food enters the esophagus, a muscular tube that connects to the stomach.The esophagus uses wave-like muscle contractions called peristalsis to push food toward the stomach.As the food reaches the end of the esophagus, it's ready to enter the stomach for the next stage of digestion.In the stomach, food mixes with acidic gastric juices containing digestive enzymes.The stomach muscles contract and relax, churning the food and gastric juices together.This mixture forms a thick liquid called chyme.The chyme then moves into the small intestine, where additional digestive juices are added.The liver produces bile while the pancreas releases digestive enzymes.These digestive juices break down nutrients into smaller molecules that can be absorbed.The partially digested food continues its journey through the small intestine.In the small intestine, tiny finger-like projections called villi increase the surface area for nutrient absorption.Digested nutrients are absorbed through the walls of these villi into the bloodstream.Undigested material moves to the large intestine, where water and minerals are absorbed.As water and minerals are absorbed, the waste material becomes more solid.The solid waste moves to the rectum where it is stored until excretion.Let's review the key points of absorption and excretion in the digestive system.And that completes our journey through the digestive system!