Interested in learning about the human digestion system?

How is it that our bodies are able to process food, and turn that into a energy source which flows through our blood? What happens to the food that we consume? These are all terrific questions, which will all be answered in this section of the Cells and Systems unit. The digestion system is by Through this page, we will be learning and better understanding the human digestion system, and the role which each organ plays in the digestion process. In this page, explore and learn about the GI tract, also known as our gut, in the process where food enters our mouths, and exits out through the anus. While this subject may be gross, its important to remember that human digestion is a very important feature of our bodies! Food is broken down into smaller molecules by enzymes, which are produced by different organs in the digestive system. The main organs involved in digestion include the mouth, esophagus, stomach, small intestine, large intestine, and anus.

Focus question : "What is the role of each organ in the human digestive system and how does food progress through it?"

The human digestive system, which travels from the mouth down to the anus, takes place in our GI system- or otherwise, known as our gut.  The GI system is the Gastrointestinal tract. Through this system, we will learn about the transportation, absorption, and digestion of food and how our bodies are capable of turning food into a reliable energy source for our bodies.

First, we have ingestion- where food enters our body. The process of the human digestive system begins at the mouth. Food enters your body, and salivary glands which produce enzymes will help to break down the food. This process is known as "chemical digestion", where chemicals help to dissolve and break down the food and its molecules. In the mouth, this is where mechanical digestion will also occur. Mechanical digestion will begin when the human mouth, composed of its 32 adult human teeth, will start breaking down the bits of food into smaller bits where we can begin the next phase of human digestion. 

The second phase of human digestion is where food will travel down the esophagus- traveling down from the mouth, all the way down to the stomach of the human being. Peristalsis is the process when wave-like muscles will help to slowly travel down the esophagus. This is a unique feature of the system, where we are able to swallow and consume food even while standing upside down (according to Ms. Ivy). Once the food is processed, it will end up in the stomach where a series of acidic fluids known as gastric acid will begin to dissolve the food through chemical digestion. Gastric acid has a pH level of roughly 1-2, meaning its extremely acidic compared to other substances. Once this process of chemical digestion is finished, it will then travel to the small intestine where the nutrients of the food will be absorbed through little villis or microvillis. This food, and the nutrients, will be absorbed into the circulatory system (aka the blood) where the nutrients will be transferred to other organs. This is because organs need energy to survive, and sustain themselves- and this is possible thanks to the help of the small intestine. It is debatable to say whether or not the small intestine is the most important and vital organ of the human digestive system, but in my personal opinion, yes it is because of its role in sustaining the role and function of the other bodily systems that keep your body going. 

The liver assists in producing bile, a type of digestive juice, which is then stored in the gallbladder- a pea-like organ which is located somewhere near the liver (i forgot where it is exactly located). This is then stored in the gallbladder- located right below the liver. This digestive juice will then be released in parts of the small intestine where it will aid in chemical digestion, aka where it helps food to break down. During the bile reflux, this juice is released onto the stomach- and in some cases, even up into the esophagus. The small intestine is responsible for many other traits, like absorbing water and other minerals, extracts water, and absorbs nutrients. Additionally, pancreatic and liver secretions are found in the small intestine where they help to further break down the food by neutralizing stomach acid. The liver is where the ingested nutrients and minerals are processed before being delivered to the rest of the body.  This complex organ is likely one of the most important organ parts of the digestive system because of the amount of duties which is possessed- and how this single organ itself is responsible for fueling and powering the other organs by providing the circulatory system with nutrients, which makes up plasma. Plasma is composed of mainly salts and protein, and is the liquid aspect of blood. The dissolved and broken down food travels to the last part of the digestive system, which is the large intestine, where the feces is then absorbed of all of its minerals and water, and gets rid of all the nutrients, salts, and bacterial waste that may be contained. This is where most of the human parasites will be left in the GI tract. Fun fact : the large intestine is also known as the gut. While you did state that the large intestine absorbs water and minerals, it is true that they absorb a majority of the minerals and liquid, but, water diffuses in response to the osmotic gradient established by sodium - in this case into the intercellular space in the small intestine, and excess water is absorbed by the walls of the small intestine- though it only plays a small responsibility in the absorption of water. The large intestine is also where a majority of the elimination process occurs. The remaining indigestible material is absorbed by the large intestine as part of the elimination process, creating solid feces by absorbing water and electrolytes. After that, the feces are forced into the rectum, where they are momentarily stored before being expelled through the anus during defecation.