Chapter 35, Problem 35A

Summary Introduction

To write:

The digestive mechanism of animals after eating any food.

Introduction:

The stomach has three basic functions; storage of food, breakdown of food into simple compounds, and mixing of food with the enzymes used for digestion. The stomach consists of a mucosa layer that is specialized cells and glands that form the hydrochloric acid and enzymes involved in the digestion process. The mucosa releases mucus that protects the inner lining of the stomach from the hydrochloric acid formed inside the stomach. Another cell that is produced inside the mucosa is the gastrin hormone that releases the enzyme and the acid from the mucosa and helps in muscle contracting of the stomach. The food gets mixed and crushed and forms chyme and the pyrrolic sphincter relax when the chyme formation gets complete. The chyme then move inside the duodenum that helps in the absorption of food that we eat.

Explanation of Solution

The digestion mechanism initiates the chewing process that involves the breaking of large food particles into small particles. During the chewing process, the saliva containing amylase gets mixed with the food, these enzymes are involved in the break-down of carbohydrates. Then there is a tube that connects the mouth and the stomach that is the esophagus. When the food gets swallowed from the esophagus it reaches the stomach, but in between the esophagus and stomach, there is a region called the sphincter so the food should cross this region to reach the stomach. The stomach is composed of an acidic environment due to the presence of enzyme pepsin that involves the protein digestion. The inner lining of the stomach is composed of mucus that prevents the stomach to get damaged from pepsin. Most of the absorption is takes place in the small intestine but few substances like aspirin and alcohol absorb by the stomach cells. After crushing and mixing the food with the digestive enzymes through the pyrrolic sphincter it moves to the small intestine. The small intestine consists of smooth muscle walls that involve mechanical digestion and through the peristalsis push the food father. In the small intestine, the digestion process involves the pancreas, liver, and gallbladder. The pancreas releases the hormone that digest fats, proteins, and carbohydrates, the liver produces bile juice that breaks the fats and excessive biles get stored in the gallbladder to be released in the small intestine while needed. After the completion f chemical digestion, the nutrients from the food get absorbed into the circulatory system.

Conclusion

Thus, the digestion mechanism starts from the mouth, and through the esophagus, it reaches the stomach. In the stomach, the food gets crushed and mixed and thus form chyme. Chemical digestion and the absorption of nutrients take place in the small intestine.