All food you eat has to pass through the same set of digestive organs that break down the food and then extract the nutrients, before expelling the waste. Food starts in the mouth before progressing through the esophagus and to the stomach, and then through the intestines and then out through the anus. Today I’m going to go more in depth onto each part of the digestive system.

All food starts in the mouth. Whether is is a mushy food or a liquid that doesn’t get much processing from the mouth, or really tough food that spends a lot of time there, everything passes through the mouth. The mouth is one of three places (the other two being the anus and the bladder) in the Gastrointestinal System that is operated by primarily Somatic Nervous System, as opposed to the Autonomic Nervous System. This means that you have to consciously chew and swallow in order to process food.

When you take a bite of solid food, it first comes into contact with your Incisor teeth, (your very front teeth) and your canines. This will bite off a chunk of food, leaving a piece outside of your mouth and one inside. If you are eating small bites, then you typically skip the front teeth, and pop it straight into your mouth, or, if you’re civilized, then you use your front teeth or your lips to pull a small bite of food off your fork. Regardless, we now have a small piece of food in our mouth for us to consume. This is where our back teeth come in. Subconsciously, your tongue moves the food to your back teeth, which are made for grinding. Once you have pulverized your food into a thick paste with the help of saliva, your tongue then forces the little ball of paste to your throat, where you then swallow, sealing of your trachea from your esophagus to let the food pass through. While this is subconscious, you can still mess up, leading to choking if some food gets into your windpipe.

If I’m quite honest, the esophagus is pretty boring. All it does is use muscles to push food paste from your throat down to your stomach. Not much else.

Your stomach is one big muscle with stomach acid glands. The stomach furthers the work of the mouth, reducing the food from a thick paste to a liquid by adding stomach acid to help break it down further and incorporate it better. The stomach has a valve that opens when the food is broken down sufficiently, and allows the food to pass into the small intestine.

The purpose of the small intestine is to separate nutrients from waste in the body. I’m not going to talk about the chemical way in which nutrients are separated (mainly because it is way over my head), but essentially the nutrients are separated, and then ejected into the blood to be carried, along with oxygen, to all the other cell that need the nutrients. Meanwhile, the bloodstream is also ejecting waste into the small intestine, like excess amounts of certain nutrients.

The small intestine flows pretty seamlessly into the large intestine. The purpose of the large intestine is to absorb the rest of the liquid and begin turning the waste into a form that is easy to expel from the body. The large intestine absorbs almost all of the remaining water and electrolytes into the body, leaving a dehydrated stool to be expelled through the anus.

The gastrointestinal system has been, by far, the most interesting part of human anatomy that I’ve learned about so far. This is mainly because I really, really love eating, and I find the way the body processes food to be very facinating.

In this essay I’m going to do my best to explain the nervous system. The Nervous System is broke into two categories: The Central Nervous System and the Peripheral Nervous System.

Nerves work sort of like electricity; and (I think) that the signals are sent a little bit like morse code. Different things send different intervals of electric signals through the nerves. The nerves are also responsible for all of the senses. Each of the sense organs (eyes, ears, tongue, nose, and skin) simply take their respective molecules, read them, and convert them into electrical pulses that run into the brain.

I’m going to start with the Peripheral Nervous System. The Peripheral Nervous system is divided into the Somatic and Autonomic Nervous Systems. The Somatic Nervous System controls thing in your body that you have to make a conscious decision to operate. If you are unconscious, these nerves basically stop responding. A good example of something controlled by the Somatic Nervous System is your fingers. The Autonomic Nervous System Controls the bodily functions that don’t take consciousness to try to operate. For example, if you are unconscious (maybe from a medication; it can be different if you’re injured), then your heart will still work without having to thing about it.

The Central Nervous System is the nerves that go down and around the spine. All the other nerves flow into the Central Nervous System which then moves the signals up to the brain.

The Endocrine System is a way that the body communicates between its different organs. The Endocrine system functions by passing hormones into the blood. Different organs send different hormones, and, depending on the hormone, the glands in different organs pick it up. This is the most prominent communication system other than the nerves inside the body. It lets different organs communicate to each other without necessarily the brain.

I’m going to do my best to describe the composition of blood and what each part of the blood does, but as I have no former science knowledge, I have had a hard time understanding all of the information presented, but I will do my best to make sense of it.

There are four main parts that compose the blood. They are as follows: Red Blood Cells; White Blood Cells; Plasma; and Platelets.

Red blood cells are probably the most well-known part of the blood. They are the cells that carry the oxygen to the other cells of the body so that they can function, and are what give the blood its red color. They are the main part of the blood.

There are a lot less white blood cells compared to the red cells, but they are important nonetheless. The white blood cells are what fight off infections and unwanted things that are in the blood, and they serve as a part of the body’s immune system.

The plasma is actually the liquid portion of the blood. It is made of mostly water, but it also contains other proteins and stuff that help the other cells in the body function.

Lastly, we have the platelets. They are cells that are there to help begin the healing process of injured tissue, by first creating a blood clot to stop leakage so that the cells can then begin to heal and the white blood cells can then fight off any foreign substances in the body.

KAAs2: The Respiratory System

Today I’m going to talk about how the respiratory system functions. For those of you that don’t know, the respiratory system is the system that provides your body with oxygen from the atmosphere of the Earth.

Let’s start at the beginning of a breath. The lungs rest between breaths. When you inhale, the process begins with your lungs expanding. This causes a vacuum in the lungs, and nature abhors a vacuum. This causes a suction effect through either your mouth or your nose. The air, composed of nitrogen, oxygen, and carbon dioxide passes to your throat, where it splits of from the esophagus and into the trachea, or windpipe. The trachea then, after passing the voice box, goes down to the lungs, where the bronchi split it between the two. The bronchi then send the air down the bronchial chain, which goes to the alveolar ducts and sac. These are what actually filter out the oxygen from the other gasses in the air, and allow it to pass the oxygen into the arteries, which, in turn, goes into the blood system. Meanwhile, carbon dioxide also exits the bloodstream and into the lungs. You lungs then contract back to their normal size, which pushes all of the carbon dioxide and nitrogen back up the way it came, past the voice box, and out of the mouth or the nose. Congratulations, you have just taken a breath!