The Importance of Digestion
Digestion is necessary for us and animals so we can have the ability to break down foods with acids stored in the stomach and teeth (which is known as chemical and mechanical digestion). "The main purpose of the digestive system is to provide the body with amino acids, carbohydrates, fats, and vitamins to keep our cells functioning." [1] This extracts the nutrients from the food and liquids that have been consumed, to put them to use by converting them into energy! The nutrients extracted are absorbed into cells to make energy. In our digestive system, we make energy, also known as ATP. ATP is a triple energized bond, and when you break off the last bond, energy is then released. After the bond is broken, it turns into ADP, which are unenergized bonds. In addition, the digestive system is needed to separate the waste from the nutrients, and to get rid of what is not needed. The digestive system also separates the fats, the liquids, and the solid feces and gets them where they need to go. An organism's digestive system is connected to organs and tubes that keeps the cycle going.
Human Digestion
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*Use the diagram to help you follow along*
The human digestive system consists of many organs and structures. First, food goes into the mouth. Next, our teeth breaks down our food and forms a bolus. The bolus then goes down the throat, which leads to the esophagus. Through the process of peristalsis, food moves along the digestive tract using muscle contractions. The esophagus lead to the stomach, which then breaks down the foods even more using enzymes and acids. Then the broken down food particles move to the small intestine that extracts the nutrients and separating it from the waste. Next, it goes to the pancreas that breaks down the fat and carbohydrates from the food eaten. The liver secretes bile, then it moves to the large intestine. The large intestine extracts the liquids from the waste. Then, the waste exits out of the body through the excretory system.
The human digestive system consists of many organs and structures. First, food goes into the mouth. Next, our teeth breaks down our food and forms a bolus. The bolus then goes down the throat, which leads to the esophagus. Through the process of peristalsis, food moves along the digestive tract using muscle contractions. The esophagus lead to the stomach, which then breaks down the foods even more using enzymes and acids. Then the broken down food particles move to the small intestine that extracts the nutrients and separating it from the waste. Next, it goes to the pancreas that breaks down the fat and carbohydrates from the food eaten. The liver secretes bile, then it moves to the large intestine. The large intestine extracts the liquids from the waste. Then, the waste exits out of the body through the excretory system.
Clam Digestion
Mollusks have a very different digestive system than humans do. Clams don't technically use their mouths like we do. One interesting factor that the Black Lipped Oyster has is filter feeding. It has the ability to absorb the food particles around it by just swimming or floating in areas with lots of particles. For the clam to be able to absorb food and oxygen, they use something called a siphon. Clams have two siphons to let water enter the clams stomach and the other is for the clam to exit the waste and water, an inhalent siphon and an exhalent siphon. The mouth is where it starts, where the particles are absorbed into the mantle and it flows to the gills. Next, the cilia trap on the gills divide the food from the water, by the mucus that is formed by the gills. Also, the food particles go through the heart and the blood flow currents, which is odd compared to the human digestive system. The food that is mixed with the mucus is then turned into a bolus, while the rest of the waste is extracted and taken out through the exhalent siphon.