Digestion is the process in which food is broken down chemically and physically into a form that can be absorbed by your small intestine, enter your blood stream and be used for energy for your cells. It's necessary in order for humans and animals to survive.
When you eat, the food enters your oral cavity, also know as your mouth and is broken down physically (chewing) and chemically (enzymes in saliva). When you swallow, the food then goes into the pharynx (the back of your throat) and goes past the epiglottis and into your esophagus. Peristalsis (muscle contractions) push it down into your stomach. It is then broken down in the stomach with enzymes. After it is broken down, it enters the small intestine. The walls of the small intestine are covered with villi. The villi absorb nutrients. They have capillary and lacteal inside of them which carry the nutrients such as glucose to your body through your blood stream. From there, it goes into your large intestine where all of the water is absorbed. Finally, the waste remaining is excreted from the anus.
How the Glucose is Used
When nutrients are absorbed through the small intestines, the nutrients (mostly glucose) are carried to your cells where in the mitochondria, cellular respiration is performed. Cellular respiration uses oxygen and glucose to produce carbon dioxide, water, and ATP. It consists of three different parts called glycolysis, the Krebs cycle, and electron transport.
ATP stands for adenosine tri phosphate. The energy that humans have is released by the ATP by breaking one of the phosphate bonds. When this happens, ATP turns into ADP. ADP stands for adenosine di phosphate and is unenergized because it has a broken bond. In order to make the third bond that turns ADP back into ATP, the energy from glucose must be used through the process of cellular respiration.
Indian red scorpions, contrary to popular belief, only use their stinger as a last resort. At night they go hunting. They wait for their prey (insects) to come and when they do, the scorpions grab their prey with their pincers. Then, without even taking the insect inside their mouth, they produce digestive juices from their preoral gut and digest it slightly. Then, the setae takes out the part of the insect that they can't eat, press it together and get rid of it. The food is then brought into the body by the muscular pharynx. Next, food goes through the pharynx, the esophagus, the mid gut, the hind gut, and is then released in the form of feces from the anus.