Final answer:
Amit's ingested food goes through a complex journey, beginning in the mouth and followed by digestion in the stomach and nutrient absorption in the small intestine. Most of the water is reabsorbed in the large intestine, converting chyme to semisolid stool, which is stored in the rectum before defecation. Constipation and diarrhea reflect imbalances in this process.
Step-by-step explanation:
When Amit has his lunch, the digestion and absorption process begins. The food travels through the alimentary canal, starting from the mouth, going down the esophagus, and into the stomach, where it is further broken down. It then passes into the small intestine, where nutrients are absorbed into the bloodstream. The small intestine absorbs about 90 percent of the water ingested, either as liquid or within solid food. After the small intestine, the remaining chyme (digested food) moves into the large intestine, or colon, where most of the remaining water is absorbed. This process converts the liquid chyme residue into semisolid feces, which are then stored in the rectum until defecation occurs.
Constipation can occur if defecation is delayed and additional water is absorbed, making feces firmer. In contrast, diarrhea can result if waste matter moves too quickly through the intestines and not enough water is absorbed. This balance in the large intestine ensures that stool is formed correctly and excreted with ease unless there is some intervention, such as the ingestion of foodborne pathogens, which can disrupt this balance.
The liver plays a vital role as it acts as a storehouse for nutrients, processes various substances, and helps in getting rid of wastes. The final step in the journey of food through the body ends with the elimination of waste through the rectum and anus, with the help of peristaltic movements signaling the need to defecate.