Your body absorbs the nutrients it needs from food through the process of digestion. This occurs as your meal passes through the digestive system and enters different digestive stages. Each stage of digestion is suited to process food in a particular way, from breaking it apart physically or chemically to extracting nutrients and expelling waste, and each digestive stage relies on the stages preceding it to properly process your meals.
Digestion Begins in Mouth
You are digesting your food the moment it enters your mouth. When you chew, you not only break your food down physically, but also expose it to saliva. As you chew your food, and it becomes soaked with saliva, it becomes softer and easier to swallow. Chewing also breaks your food into smaller parts, which your digestive system can process more quickly than it can larger pieces of food. The smaller, softer pieces of food this process produces are called bolus. When you swallow, the bolus you have made begins its journey from the mouth, down the esophagus and through the esophageal sphincter to the stomach.
Stomach
After bolus enters the stomach, it comes into contact with hydrochloric acid. Your stomach acids continue the process that started in your mouth, breaking food particles down further and eventually liquefying the bolus. In this liquid state, the partially-digested remains of your meal are called chyme. Once your food has become chyme, it exits the stomach and moves to the small intestine.
Chyme's Journey Through Small Intestine
In the small intestine, chyme is exposed to digestive enzymes from the pancreas, gallbladder and liver. These enzymes convert the chyme into simpler elements that are easily absorbed by the body. Villi, which are tiny finger-like projections, extend from the interior lining of the small intestine and absorb digested food into your bloodstream. What remains of your meal after this point passes through the ileocecal valve and into the large intestine, where the process of waste excretion begins.
Waste Extraction
Few nutrients are left in chyme by the time it reaches the large intestine. What remains is waste, and it is in the large intestine that your body first begins to process this waste. At this stage, your body reabsorbs water from the waste, and it becomes more solid. This solid waste continues to travel through the large intestine and finally collects in the rectum at the end of your large intestine. Once there, the waste remains until you eliminate the solid waste out through your anus.
Member Comments