Human Digestive System Overview Quiz

Human Digestive System Overview

The human digestive system is essentially a series of organs that work together to transform food into nutrients your body can absorb and utilize. These organs form two major divisions: an upper alimentary canal that transports food from mouth to stomach, and a lower gastrointestinal tract where most of the actual processing occurs.

Upper Alimentary Canal

The first part of this process begins with the teeth, which mechanically break down large chunks of food. This initiation of the breakdown process enables easier access for enzymes to attack food molecules, starting the chemical process of digestion. Saliva also plays an essential role by moistening the food and containing enzymes that initiate the chemical process of carbohydrate digestion.

Mouth

Inside the mouth, there are small pits located on the tongue called papillae, filled with taste buds that help identify foods' nature. The back section of the tongue has microscopic hair-like structures called taste buds, each with specialized cells named receptor cells. They send information to the brain via the cranial nerve, allowing you to enjoy different flavors like sweet, salty, sour, bitter, and umami.

Esophagus

After chewing, the partially digested food is swallowed and passes through the esophagus. Located behind the windpipe, it acts as a conduit between your mouth and stomach. It contains muscles that contract rhythmically to push the food towards the stomach.

Stomach

The stomach serves as the mixing chamber of the digestive system. It secretes gastric juices containing hydrochloric acid, mucus, and the enzyme pepsin, breaking down proteins, killing bacteria, and dissolving the food particles. In addition to the stomach's inner lining, the esophagus possesses a sphincter, a circular muscle that contracts to prevent the contents from moving back into the esophagus.

Lower Gastrointestinal Tract

This part of the digestive system is made up of small intestine, liver, gallbladder, and pancreas.

Small Intestine

The role of the small intestine is to break down food particles into smaller ones. It is lined with glands that release digestive enzymes into the intestinal lumen, breaking down proteins, carbohydrates, and fats into their respective monomers. The small intestine is also responsible for the absorption of these nutrients into the circulatory system, which is then transported to the liver for processing.

Liver

The liver is an integral organ in the human body. It plays a vital role in the digestive system, particularly in the small intestine. It produces bile, which is stored in the gallbladder. The bile emulsifies fats, breaking them into small droplets, making them more accessible to lipase enzymes present in the intestine. This emulsification allows for proper absorption of fats into the bloodstream.

Gallbladder

The gallbladder stores bile produced by the liver until it is needed to aid in fat digestion. When food enters the small intestine, the gallbladder contracts, releasing bile into the duodenum, the initial segment of the small intestine.

Pancreas

The pancreas produces both pancreatic juice and insulin hormone. It releases the pancreatic juice into the small intestine, containing enzymes like amylases, proteases, and lipases, responsible for further breaking down carbohydrates, proteins, and fats respectively. Additionally, amylase continues its action within the small intestine, converting complex sugars into simple ones to facilitate their transportation across cell membranes.