Did you know that our bodies create about a gallon of mucus in just two days? I do! In fact, I know a lot of other interesting information about the human body, and YOU WILL TOO if you read my paper! Within this document, you will find six different body system essays. These six essays focus on the muscular, skeletal, circulatory, respiratory, digestive, and nervous systems, which all work together to operate our body. All of these systems have different components, each with their own unique functions that help to keep us alive. However, each system cannot operate alone - they need each other to be successful. For example, the nutrients gathered by the digestive system get distributed throughout the body in the circulatory system! Over the past 12 weeks, we gathered information, organized our thoughts, and paraphrased what trusted websites taught us about each system. We worked with responsibility partners and our papers definitely benefited from the collaboration. Just like each human body system needs to rely on the other systems, we relied on each other to improve our writing and our process. The following is the result of our hard work...
Our skeletal system is made up of 206 bones. These bones work together to provide our body with support so that we can stand, help us to move so we can walk around, and protect our vital organs like our and our brain! Our bones even make and store blood cells for our circulatory system! Without our bones, we would be nothing more than a pile of skin and muscle, and organs on the floor. We wouldn’t be able to move and our organs wouldn’t be safe.
Our bones are made up of many layers. These layers are important because we need our bones to be strong, yet lightweight. In order to achieve this goal, the outside layer of bone is made up of solid, compact bone that makes our bones that makes our bones strong and dense. The next layer of bone is called Cancellous (a.k.a spongy bone). This layer allows our bones to be lightweight and into bone marrow. Bone marrow is a thick and spongy section in the middle of bone where red and white blood cells are formed. Finally, our bones are all covered in a thin membrane called periosteum which is where our muscles attach to bones. So that is how bones are structured in order to keep our bodies strong, yet lightweight!
Our skeletal system is made up of 206 bones. These bones work together to provide our body with support so that we can stand, help us to move so we can walk around, and protect our vital organs like our and our brain! Our bones even make and store blood cells for our circulatory system! Without our bones, we would be nothing more than a pile of skin and muscle, and organs on the floor. We wouldn’t be able to move and our organs wouldn’t be safe.
Our bones are made up of many layers. These layers are important because we need our bones to be strong, yet lightweight. In order to achieve this goal, the outside layer of bone is made up of solid, compact bone that makes our bones that makes our bones strong and dense. The next layer of bone is called Cancellous (a.k.a spongy bone). This layer allows our bones to be lightweight and into bone marrow. Bone marrow is a thick and spongy section in the middle of bone where red and white blood cells are formed. Finally, our bones are all covered in a thin membrane called periosteum which is where our muscles attach to bones. So that is how bones are structured in order to keep our bodies strong, yet lightweight!
Although bones are extremely important, we wouldn’t be able to move without joints! Joints are place where two or more joints meet. There are several types of joints in our bodies, but we’ll just focus on four of them. The first type of joint is called a hinge joint. Just like the hinges on a door, they allow movement back and forth. We have hinge joints at our elbows and knees, and we even have them at our knuckles! Another type of joint is called a ball and socket joint. This is where one bone has a ball at the end of it and the other bone has a “basketball mitt” for the ball to sit in. Our shoulders and hips are examples of ball and socket joints. The third type of joint that we studied was called a gliding joint. Gliding joints are places where two or more joints meet and slide by each other. Our wrists and ankles are two examples of gliding joints. The last type of joint is called the pivot joint. A pivot joint works when one bone acts like a ring and the other bone sits inside the ring and rotates. Our neck is an example of a pivot joint because it can rotate around and move up and down. At each joint a soft, squishy material can be found between bones which keeps them from rubbing together, which would be painful. This material is called cartilage. Cartilage, which is bendable, can also be found in our ears and nose. But all of this wouldn’t be possible if it weren’t for ligaments keeping our bones together at each joint. Ligaments are long, stretchy tissue that connect bone to other bone and stabilize joints. Without these ligaments in place, bones wouldn’t stay attached to each other and wouldn’t allow joints to move. It’s interesting to know that people that are double-jointed actually just have extremely stretchy ligaments! Joints definitely make movement possible and without them, we’d have a hard time getting around our world!
Bones definitely are important parts of the human body. They allow us to move, help provide us structure and support, protect our important organs, and even make blood cells! Because bones are designed so well, they are strong, yet lightweight. Thanks to joints, ligaments, and cartilage, we are able to bend and move throughout our world. Finally, the muscles in our body attach to bones, giving us the power to actually move around!
The muscular system helps the human body move around and have fun. Let”s say that you want to move your arms, eat a sandwich, or run, you use muscles! There are many different types of muscles, and they all serve different purposes (e.g movement, pumping blood, dilating your pupils). Some of these purposes are controlled by us while others are controlled automatically by the muscle cell or the brain.
There are two types of categories of muscles in the human body: voluntary and involuntary. Voluntary muscles are muscles that we have control over. They are muscles that control our body’s movement and are attached to bones. Skeletal muscles are the only type of voluntary muscles in our body. They pull on bones to cause us to move. Skeletal muscles never push, they only pull, and that’s why they are nearly always found in pairs. One example of this is the biceps and triceps that are located in our upper arms. When one set of muscles, like the biceps, want to pull the lower arm up, they contract, or shrink, while the triceps relax, or expand. When the triceps pull the arm down, the contract while the biceps relax. This is an example of a pair of muscles working together to make movement. But those muscle wouldn’t be able to do any of this without tendons connecting them to the bones that they move. Tendons are flexible bands of tissue that blend into bones and enable them to move the bones that they were supposed to move. Although skeletal muscles are the only type of voluntary muscles, there are two different types of involuntary muscles.
Unlike voluntary muscles, involuntary muscles do things automatically without us knowing it. There are two examples of involuntary muscles. They are cardiac muscle and smooth muscle. Cardiac and smooth muscles are similar because they both work automatically, by themselves. Cardiac muscles are muscles that are found in our heart, and are responsible for pumping blood throughout our body. They work without us thinking about them, and they contract and relax throughout our entire lives. Smooth muscles are found inside many of our organs like the intestines, esophagus, stomach, and bladder and help move food through our body. Smooth muscles can also be found in your eyes and blood vessels. Smooth muscle cells may look like one big cell, but are actually a bunch of smaller, smooth cells all grouped together (unlike the striated, skeletal cells). So clearly, there are many types of involuntary muscles that do important tasks like pumping blood and digesting food!
The muscular system is a powerful system that allows us to move, convert food into energy, and circulate blood throughout our body. Our muscles make up of half of our body weight and give our body tone and shape. In the next essay, learn how some of these muscles move blood throughout our body in order to deliver oxygen to all of our cells.
Why is blood red? Why does our heart beat? These are all questions you will have the answer to by the end of this paragraph. The circulatory system is made up of many parts, each one more interesting than the other. This synchronized system is always in effect and requires many parts for it to work. One of these parts is a liquid called blood.
Blood is essential for the human body. It carries important nourishment to the cells and transports our own waste. Blood is made up of many types of cells. Red blood cells are in charge of transporting oxygen and collecting carbon dioxide, or waste, to expel it from the body through the lungs. Red blood cells also contain hemoglobin, an important chemical that gives blood its red color. White blood cells, however, help us fight infections by moving out of the bloodstream to reach affected tissue. Usually there aren’t many white blood cells in your blood, however, the body makes more when you get sick. Although white blood cells help fight disease, who helps heal cuts and scrapes? That’s when platelets come in. They make sure that when you get cut, blood doesn’t keep on flowing out of you. These small, round cells go to broken blood vessels, or cuts, and start to stick inside the vessel. Then, clotting factors make a web of protein threads. When the web and platelets come together, they become a blood clot. The blood clot then dries up to become a scab while the skin heals. Without platelets, a small scrape would have to be stitched up! The last component of our blood is plasma. Plasma is a yellowing liquid that makes up over 50% of our blood. It carries important hormones, nutrients, and proteins through the body. Clearly, blood is key for good health and we couldn’t survive without it!
For blood to be able to move through the body, it needs blood vessels. Blood vessels are little tubes that transport blood. There are three types of blood vessels: arteries, capillaries, and veins. Arteries transport oxygenated blood, or blood that has received oxygen from the lungs, throughout the body. They are responsible for giving oxygen to the billions of cells in our body. As blood travels outward, the arteries become smaller and smaller until they become capillaries. They are so small that blood cells can usually only go through one by one. Waste, like carbon dioxide, is released into the blood within the capillaries. Once blood goes through the capillaries, it goes into the veins. Veins take blood back to the lungs and heart, where the waste gets breathed out and more oxygen can be released into the blood. Blood vessels, as you now know, are very important because they transport blood through the body!
The last, but very important part of the circulatory system is the heart. The heart’s main job is to get blood from the body and pump it to the lungs so it gets oxygenated and pump that blood back into the body. This task is divided and conquered by the two sides of the heart, the right and left. The right side takes deoxygenated blood and pumps it to the heart, while the left side does the opposite. But the right and left sides don’t do it all at once. The job of each parts is divided and conquered by two other parts that make up the right or left. These are called the atrium and the ventricle. There are in total two atriums and two ventricles, one in each side of the heart. Together, they are called the four chambers. The right atrium, or the atrium in the right side of the heart, takes blood from the body, which doesn’t have oxygen in it, therefore considered deoxygenated blood, and pumps it into the right ventricle. The right ventricle, located just under the right atrium, pumps the deoxygenated blood into the lungs, where it will get oxygenated, or full of oxygen. At that point, the left atrium, located in the upper left corner of the heart, takes that oxygenated blood and pumps it into the left ventricle, which is right under it. The left ventricle then puts the blood in the arteries for the system to start again!
The circulatory system is remarkable in many ways. First, it is beautifully synchronized. If one thing goes wrong, it will ruin that synchroni. Luckily, the circulatory system is so unflawed that it’s almost impossible. Second, the whole body body depends on this system. Without it, we would die in a matter a minutes. In the next paragraph, learn about how blood is oxygenated and what parts of the body are used in the process.
Some people think air is 100% oxygen. That is incorrect. In fact, it is only 50% oxygen. the other 50% is a mix of nitrogen and carbon dioxide. If air was 100% oxygen, we would all die. Anyways, we still need oxygen to survive. It needs to oxygenate our blood, which will take it to all the cells in our body. All you have to do is inhale, but much more happens inside of you than you think. In this paragraph, learn what goes on in your neck and lungs when you inhale.
Air enters the body through the mouth or nose. Although we can get air through both areas, our bodies were made for breathing through the nose. Doctors know this because of the nasal passage, located in the nose. The nose has hairs that prevents unwanted particles, like dust and soot, from going into the nasal passage while a sticky substance, called mucus, traps germs before they can get into your lungs. When you inhale, the air goes through the nasal passage and to the pharynx. The pharynx, more commonly known as the throat, is also part of the digestive system, which you will later learn about. At the bottom of the throat, there are two tubes: the esophagus and the larynx. While the esophagus is for food only, air goes through the larynx, whose entrance is guarded by the epiglottis. The epiglottis, a flap in your throat that blocks off the windpipe when food or liquid is being swallowed. When you aren’t eating, the epiglottis stays open. The larynx, or voice box, is where sound is made. The pitch and volume you sing or talk at is controlled there. But the larynx has another job. It has to get air into the trachea. To do this,air must go through the vocal cords, two identical flaps located at the end of the larynx. These flaps stand in a vertical position right next to each other, where they make what looks like a small slit. When air needs to go through them, they relax and open. This makes a wide opening in which air goes through to enter the trachea. The trachea, or windpipe, is the last step for air to get into the lungs. Half of the trachea’s 5in length is in the lungs, while the other half is in the neck. The end of the trachea is split into two tubes, called the bronchus. Once air goes through the trachea, it is officially in the lungs.
The main purpose of the lungs is to get oxygen into the blood. To do this, though, it needs to get through many places. The first thing air needs to get through are the bronchus. There are two of them, one in the left lung and the other on the right. The bronchus then split into several smaller tubes, called the bronchi. There are about 30,000 of these in the lungs! The bronchi then split into about 300 million, in total, little alveoli. The alveoli are little sacs at the end of each bronchi that fill with air when you inhale. Oxygen then passes through the walls of the alveoli one cell at a time and goes into every blood cell in the surrounding capillaries. Then, the capillaries send the now oxygenated blood to the heart to be pumped back into the body. This process is called Exchange of Gasses, and it is key to our survival. It is also the main purpose of the respiratory system and why we have lungs!
The process I have just showed you takes only a matter of seconds. Even though it happens in a snap, it is extremely important and something we can’t live without. Whenever you are out of breath, whether it's from running, talking, or anything, it means that your blood needs to receive oxygen soon. In the next paragraph, learn about a system that takes place just below the respiratory system, called the digestive system.
Every time you pop a chocolate in your mouth, eat hot dogs with your family, or even just have a light snack, you need your digestive system. This active, rather timely system is how the body gets it’s nutrients and the reason why you poop. When you eat, food doesn’t just plop down into your body and exits in the form of poop. In fact, it is a long, complex process, and it commences in the mouth.
The digestive system starts with the mouth. Before you even swallow, this powerful, involuntary system is already in action. When you put something in your mouth, like a fruit, something called mechanical digestion begins. Mechanical digestion is important because we can't swallow anything that is completely solid. It breaks down food into smaller chunks when your teeth crush any food in your mouth. Although mechanical digestion breaks down a good deal of food, it needs to be broken down even more. That's when chemical digestion comes in. Chemical digestion is when saliva breaks down food. This is possible because saliva contains a substance called enzyme, which can break down food. Once food is broken down in the mouth, it isn’t considered a “hamburger” or “liquorice” anymore. It is now a bolus, which can be swallowed. Now, the bolus needs to get to the back of the throat. The tongue helps by pushing the bolus to the back of the throat, or pharynx. As you learned in the last paragraph, the epiglottis blocks off the larynx when you swallow a bolus. The bolus goes through a different tube, called the esophagus. This 10 inch tube connects the pharynx to the stomach, where the digestive system continues. Bolus travels through the esophagus and goes into the stomach, but it doesn't just slide through. The walls of the esophagus, lined with smooth muscle, tighten and relax to create a wave-like movement called peristalsis. This movement can happen in reverse, which cause food to go back up the esophagus. In other words, this happens when you vomit. As you know, at the bottom of the esophagus, there is the stomach, a stretchy sack shaped like a J. The main purpose of it is to break down food even more to make it a thick liquid called chyme. To do this, it acts as a mixing bowl. It churns together bolus to break it down. Along with the movement, the stomach needs help from digestive juices. These juices are squirted into the stomach and decompose food. When this process is over, you are left with a thick, soupy liquid called chyme, which gets squirted into the small intestine.
The small intestine, which unlike it’s name is 23 feet long, is where food is broken down even more. This time, though, the nutrients in the chyme are broken down. Fats, proteins, carbohydrates, etc. are broken down by pancreatic enzymes, which are created in the pancreas. The pancreas, a long, flat gland in the abdomen behind the stomach, produces these enzymes and releases them into the small intestine to help with digestion. Now that the nutrients are broken down, where do they go? That's when the villi come in. A villus is a microscopic, finger-like projection. Millions of them line the inner walls of the small intestine. They absorb nutrients into the body, including carbs and protein. Now that the nutrients are absorbed into the body, you are left with two things: waste, which is the parts of the food you don’t need, and fat. The villi can’t absorb fat into the body, so the small intestine counts on the liver and gallbladder to complete this task.
The liver is crucial to digestion. It produces bile, a thick, yellow-green substance. When you eat fatty foods, bile gets into the small intestine and absorbs the fat. But when you aren’t eating, bile is stored in the gallbladder, an organ located inferior and posterior to the liver. Bile stays there until it has to be used. Now, we are left with one thing, waste. In other words, poop. But to be able to get pooped out, though, it needs to go through the large intestine. This five footer is only a few inches long when inside of you. It wraps around the small intestine and ends at your buttock. The waste travels through the large intestine and gets to the end. Although the waste is ready to be pooped out, you still need time to get to a bathroom. The anus prevents waste from coming out at any random time. It closes when you don’t want the waste to leave the body yet, and opens when you do. Well, now you know how far food travels in your body and how many times it changes into something different!
This process, which takes about six to eight hours, is extremely important in many ways. It helps us get the nutrients we need in an organized, planned fashion. The most incredible part of the digestive system is that it’s mainly involuntary. Your don’t have to tell your stomach “Squirt chyme into small intestine” because it does it by itself. Also, you usually don’t feel a thing! In the next paragraph, learn about how messages are sent to different parts of the body and what they do.
Why do you flinch when something is thrown at you? Why do you draw back your hand when you touch something too cold? How does your brain control your body? This all happens because of the nervous system. Every move you make, whether it’s a wink or a stomp, isn’t possible without this fast, powerful system. In the next two paragraphs, learn about how, with the help of millions of nerves, you can make movement possible.
The brain is, undoubtedly, one of the most important parts of the body. It is the center of information and helps us complete tasks, like walking, talking, and processing information. But to be able to fulfill so many duties, it is separated into different parts, which do different things. The first, and biggest, part of the brain is the cerebrum. The cerebrum is the biggest part of the brain, making up 85% of the brain’s weight. It’s outer layer processes information given to us by our five senses, sight, smell, sound, touch, and taste, to know how to react to the world around us. Other parts of the cerebrum control movement of the muscles. But that’s not all this big, grey, sponge-looking part of the brain does. Because of it, you have the ability to think, learn, and have a personality. Although the cerebrum seems like the most important part of the brain, it still needs two other parts to be useful. One of them is the cerebellum. The cerebellum helps us stay balanced. Without it, we wouldn’t be able to stand straight! That leads us to the last part of the brain, the medulla. The medulla, or brainstem, controls involuntary muscles. For example, it keeps your heart beating and your lungs filling up with air. But this rather tube-like section of the brain has another job. It brings electrical messages that were sent by nerves around the body to the brain, a process you will learn about in the next paragraph.
We’ve all been told that the brain controls everything; Your arms, your legs, your torso, etc. But how exactly does the brain do this? Well, the answer is with nerves. We have over 1 trillion of these long, thin strands spread throughout our body. Their main job is to carry messages to and fro the brain. To do this, though, there are two types of them in our body. One of them is called sensory nerves. This specific type of nerve is in charge of sending messages to the brain from the five senses. For example, if you touch something hot, the sensory nerves will send a message to the brain. But sensory nerves don’t make you draw back your hand. That is the job of the motor nerves. They take messages from the brain and send them to different parts of your body. But when these two types of nerves deliver messages, they are never delivered directly to the brain or body, but through the spinal cord. The spinal cord, an extremely long nerve that runs down your back, takes messages from sensory nerves and sends them to the brain and takes messages from the brain to send them to the motor nerves. But how exactly do nerves send messages around the body? Most of the work is done by neurons. Nerves are made of neurons, which consist of three major parts. One of them is a synapse. A synapse is a structure that allows a message pass from a neuron to another. After that, it goes through dendrites, which brings the message to the cell body. After that, axons take that message away from the cell body and to the next neuron. Well, now you know how far a message has to go for you to move a finger!
The most incredible part of the nervous system is how fast it is. A small electrical pulse, or message, has to travel through trillions of dendrites and axons in much less than a second for us to react to different situations. Next time you walk, talk, or do any movement, think about this powerful, amazing system and what you would do without it!
In conclusion, the human body has many systems that each work hard to do specific jobs to benefit our bodies, but they also work together safely to ensure our well-being. The skeletal system provides us support, protection and structure while the muscular system allows us to move, breathe, and digest food. The circulatory system transports oxygen and nutrients to the cells of our body while getting rid of waste products and the respiratory system swaps out the oxygen and carbon dioxide. Finally, the digestive system converts food into energy while the nervous system uses that energy to make decisions and maintain memories. I appreciate the time you took to read these essays and hope that you learned something valuable. So the next time you move a muscle or take in a breath, I hope you’ll think about how impressive our human body really is!
Bones definitely are important parts of the human body. They allow us to move, help provide us structure and support, protect our important organs, and even make blood cells! Because bones are designed so well, they are strong, yet lightweight. Thanks to joints, ligaments, and cartilage, we are able to bend and move throughout our world. Finally, the muscles in our body attach to bones, giving us the power to actually move around!
The muscular system helps the human body move around and have fun. Let”s say that you want to move your arms, eat a sandwich, or run, you use muscles! There are many different types of muscles, and they all serve different purposes (e.g movement, pumping blood, dilating your pupils). Some of these purposes are controlled by us while others are controlled automatically by the muscle cell or the brain.
There are two types of categories of muscles in the human body: voluntary and involuntary. Voluntary muscles are muscles that we have control over. They are muscles that control our body’s movement and are attached to bones. Skeletal muscles are the only type of voluntary muscles in our body. They pull on bones to cause us to move. Skeletal muscles never push, they only pull, and that’s why they are nearly always found in pairs. One example of this is the biceps and triceps that are located in our upper arms. When one set of muscles, like the biceps, want to pull the lower arm up, they contract, or shrink, while the triceps relax, or expand. When the triceps pull the arm down, the contract while the biceps relax. This is an example of a pair of muscles working together to make movement. But those muscle wouldn’t be able to do any of this without tendons connecting them to the bones that they move. Tendons are flexible bands of tissue that blend into bones and enable them to move the bones that they were supposed to move. Although skeletal muscles are the only type of voluntary muscles, there are two different types of involuntary muscles.
Unlike voluntary muscles, involuntary muscles do things automatically without us knowing it. There are two examples of involuntary muscles. They are cardiac muscle and smooth muscle. Cardiac and smooth muscles are similar because they both work automatically, by themselves. Cardiac muscles are muscles that are found in our heart, and are responsible for pumping blood throughout our body. They work without us thinking about them, and they contract and relax throughout our entire lives. Smooth muscles are found inside many of our organs like the intestines, esophagus, stomach, and bladder and help move food through our body. Smooth muscles can also be found in your eyes and blood vessels. Smooth muscle cells may look like one big cell, but are actually a bunch of smaller, smooth cells all grouped together (unlike the striated, skeletal cells). So clearly, there are many types of involuntary muscles that do important tasks like pumping blood and digesting food!
The muscular system is a powerful system that allows us to move, convert food into energy, and circulate blood throughout our body. Our muscles make up of half of our body weight and give our body tone and shape. In the next essay, learn how some of these muscles move blood throughout our body in order to deliver oxygen to all of our cells.
Why is blood red? Why does our heart beat? These are all questions you will have the answer to by the end of this paragraph. The circulatory system is made up of many parts, each one more interesting than the other. This synchronized system is always in effect and requires many parts for it to work. One of these parts is a liquid called blood.
Blood is essential for the human body. It carries important nourishment to the cells and transports our own waste. Blood is made up of many types of cells. Red blood cells are in charge of transporting oxygen and collecting carbon dioxide, or waste, to expel it from the body through the lungs. Red blood cells also contain hemoglobin, an important chemical that gives blood its red color. White blood cells, however, help us fight infections by moving out of the bloodstream to reach affected tissue. Usually there aren’t many white blood cells in your blood, however, the body makes more when you get sick. Although white blood cells help fight disease, who helps heal cuts and scrapes? That’s when platelets come in. They make sure that when you get cut, blood doesn’t keep on flowing out of you. These small, round cells go to broken blood vessels, or cuts, and start to stick inside the vessel. Then, clotting factors make a web of protein threads. When the web and platelets come together, they become a blood clot. The blood clot then dries up to become a scab while the skin heals. Without platelets, a small scrape would have to be stitched up! The last component of our blood is plasma. Plasma is a yellowing liquid that makes up over 50% of our blood. It carries important hormones, nutrients, and proteins through the body. Clearly, blood is key for good health and we couldn’t survive without it!
For blood to be able to move through the body, it needs blood vessels. Blood vessels are little tubes that transport blood. There are three types of blood vessels: arteries, capillaries, and veins. Arteries transport oxygenated blood, or blood that has received oxygen from the lungs, throughout the body. They are responsible for giving oxygen to the billions of cells in our body. As blood travels outward, the arteries become smaller and smaller until they become capillaries. They are so small that blood cells can usually only go through one by one. Waste, like carbon dioxide, is released into the blood within the capillaries. Once blood goes through the capillaries, it goes into the veins. Veins take blood back to the lungs and heart, where the waste gets breathed out and more oxygen can be released into the blood. Blood vessels, as you now know, are very important because they transport blood through the body!
The last, but very important part of the circulatory system is the heart. The heart’s main job is to get blood from the body and pump it to the lungs so it gets oxygenated and pump that blood back into the body. This task is divided and conquered by the two sides of the heart, the right and left. The right side takes deoxygenated blood and pumps it to the heart, while the left side does the opposite. But the right and left sides don’t do it all at once. The job of each parts is divided and conquered by two other parts that make up the right or left. These are called the atrium and the ventricle. There are in total two atriums and two ventricles, one in each side of the heart. Together, they are called the four chambers. The right atrium, or the atrium in the right side of the heart, takes blood from the body, which doesn’t have oxygen in it, therefore considered deoxygenated blood, and pumps it into the right ventricle. The right ventricle, located just under the right atrium, pumps the deoxygenated blood into the lungs, where it will get oxygenated, or full of oxygen. At that point, the left atrium, located in the upper left corner of the heart, takes that oxygenated blood and pumps it into the left ventricle, which is right under it. The left ventricle then puts the blood in the arteries for the system to start again!
The circulatory system is remarkable in many ways. First, it is beautifully synchronized. If one thing goes wrong, it will ruin that synchroni. Luckily, the circulatory system is so unflawed that it’s almost impossible. Second, the whole body body depends on this system. Without it, we would die in a matter a minutes. In the next paragraph, learn about how blood is oxygenated and what parts of the body are used in the process.
Some people think air is 100% oxygen. That is incorrect. In fact, it is only 50% oxygen. the other 50% is a mix of nitrogen and carbon dioxide. If air was 100% oxygen, we would all die. Anyways, we still need oxygen to survive. It needs to oxygenate our blood, which will take it to all the cells in our body. All you have to do is inhale, but much more happens inside of you than you think. In this paragraph, learn what goes on in your neck and lungs when you inhale.
Air enters the body through the mouth or nose. Although we can get air through both areas, our bodies were made for breathing through the nose. Doctors know this because of the nasal passage, located in the nose. The nose has hairs that prevents unwanted particles, like dust and soot, from going into the nasal passage while a sticky substance, called mucus, traps germs before they can get into your lungs. When you inhale, the air goes through the nasal passage and to the pharynx. The pharynx, more commonly known as the throat, is also part of the digestive system, which you will later learn about. At the bottom of the throat, there are two tubes: the esophagus and the larynx. While the esophagus is for food only, air goes through the larynx, whose entrance is guarded by the epiglottis. The epiglottis, a flap in your throat that blocks off the windpipe when food or liquid is being swallowed. When you aren’t eating, the epiglottis stays open. The larynx, or voice box, is where sound is made. The pitch and volume you sing or talk at is controlled there. But the larynx has another job. It has to get air into the trachea. To do this,air must go through the vocal cords, two identical flaps located at the end of the larynx. These flaps stand in a vertical position right next to each other, where they make what looks like a small slit. When air needs to go through them, they relax and open. This makes a wide opening in which air goes through to enter the trachea. The trachea, or windpipe, is the last step for air to get into the lungs. Half of the trachea’s 5in length is in the lungs, while the other half is in the neck. The end of the trachea is split into two tubes, called the bronchus. Once air goes through the trachea, it is officially in the lungs.
The main purpose of the lungs is to get oxygen into the blood. To do this, though, it needs to get through many places. The first thing air needs to get through are the bronchus. There are two of them, one in the left lung and the other on the right. The bronchus then split into several smaller tubes, called the bronchi. There are about 30,000 of these in the lungs! The bronchi then split into about 300 million, in total, little alveoli. The alveoli are little sacs at the end of each bronchi that fill with air when you inhale. Oxygen then passes through the walls of the alveoli one cell at a time and goes into every blood cell in the surrounding capillaries. Then, the capillaries send the now oxygenated blood to the heart to be pumped back into the body. This process is called Exchange of Gasses, and it is key to our survival. It is also the main purpose of the respiratory system and why we have lungs!
The process I have just showed you takes only a matter of seconds. Even though it happens in a snap, it is extremely important and something we can’t live without. Whenever you are out of breath, whether it's from running, talking, or anything, it means that your blood needs to receive oxygen soon. In the next paragraph, learn about a system that takes place just below the respiratory system, called the digestive system.
Every time you pop a chocolate in your mouth, eat hot dogs with your family, or even just have a light snack, you need your digestive system. This active, rather timely system is how the body gets it’s nutrients and the reason why you poop. When you eat, food doesn’t just plop down into your body and exits in the form of poop. In fact, it is a long, complex process, and it commences in the mouth.
The digestive system starts with the mouth. Before you even swallow, this powerful, involuntary system is already in action. When you put something in your mouth, like a fruit, something called mechanical digestion begins. Mechanical digestion is important because we can't swallow anything that is completely solid. It breaks down food into smaller chunks when your teeth crush any food in your mouth. Although mechanical digestion breaks down a good deal of food, it needs to be broken down even more. That's when chemical digestion comes in. Chemical digestion is when saliva breaks down food. This is possible because saliva contains a substance called enzyme, which can break down food. Once food is broken down in the mouth, it isn’t considered a “hamburger” or “liquorice” anymore. It is now a bolus, which can be swallowed. Now, the bolus needs to get to the back of the throat. The tongue helps by pushing the bolus to the back of the throat, or pharynx. As you learned in the last paragraph, the epiglottis blocks off the larynx when you swallow a bolus. The bolus goes through a different tube, called the esophagus. This 10 inch tube connects the pharynx to the stomach, where the digestive system continues. Bolus travels through the esophagus and goes into the stomach, but it doesn't just slide through. The walls of the esophagus, lined with smooth muscle, tighten and relax to create a wave-like movement called peristalsis. This movement can happen in reverse, which cause food to go back up the esophagus. In other words, this happens when you vomit. As you know, at the bottom of the esophagus, there is the stomach, a stretchy sack shaped like a J. The main purpose of it is to break down food even more to make it a thick liquid called chyme. To do this, it acts as a mixing bowl. It churns together bolus to break it down. Along with the movement, the stomach needs help from digestive juices. These juices are squirted into the stomach and decompose food. When this process is over, you are left with a thick, soupy liquid called chyme, which gets squirted into the small intestine.
The small intestine, which unlike it’s name is 23 feet long, is where food is broken down even more. This time, though, the nutrients in the chyme are broken down. Fats, proteins, carbohydrates, etc. are broken down by pancreatic enzymes, which are created in the pancreas. The pancreas, a long, flat gland in the abdomen behind the stomach, produces these enzymes and releases them into the small intestine to help with digestion. Now that the nutrients are broken down, where do they go? That's when the villi come in. A villus is a microscopic, finger-like projection. Millions of them line the inner walls of the small intestine. They absorb nutrients into the body, including carbs and protein. Now that the nutrients are absorbed into the body, you are left with two things: waste, which is the parts of the food you don’t need, and fat. The villi can’t absorb fat into the body, so the small intestine counts on the liver and gallbladder to complete this task.
The liver is crucial to digestion. It produces bile, a thick, yellow-green substance. When you eat fatty foods, bile gets into the small intestine and absorbs the fat. But when you aren’t eating, bile is stored in the gallbladder, an organ located inferior and posterior to the liver. Bile stays there until it has to be used. Now, we are left with one thing, waste. In other words, poop. But to be able to get pooped out, though, it needs to go through the large intestine. This five footer is only a few inches long when inside of you. It wraps around the small intestine and ends at your buttock. The waste travels through the large intestine and gets to the end. Although the waste is ready to be pooped out, you still need time to get to a bathroom. The anus prevents waste from coming out at any random time. It closes when you don’t want the waste to leave the body yet, and opens when you do. Well, now you know how far food travels in your body and how many times it changes into something different!
This process, which takes about six to eight hours, is extremely important in many ways. It helps us get the nutrients we need in an organized, planned fashion. The most incredible part of the digestive system is that it’s mainly involuntary. Your don’t have to tell your stomach “Squirt chyme into small intestine” because it does it by itself. Also, you usually don’t feel a thing! In the next paragraph, learn about how messages are sent to different parts of the body and what they do.
Why do you flinch when something is thrown at you? Why do you draw back your hand when you touch something too cold? How does your brain control your body? This all happens because of the nervous system. Every move you make, whether it’s a wink or a stomp, isn’t possible without this fast, powerful system. In the next two paragraphs, learn about how, with the help of millions of nerves, you can make movement possible.
The brain is, undoubtedly, one of the most important parts of the body. It is the center of information and helps us complete tasks, like walking, talking, and processing information. But to be able to fulfill so many duties, it is separated into different parts, which do different things. The first, and biggest, part of the brain is the cerebrum. The cerebrum is the biggest part of the brain, making up 85% of the brain’s weight. It’s outer layer processes information given to us by our five senses, sight, smell, sound, touch, and taste, to know how to react to the world around us. Other parts of the cerebrum control movement of the muscles. But that’s not all this big, grey, sponge-looking part of the brain does. Because of it, you have the ability to think, learn, and have a personality. Although the cerebrum seems like the most important part of the brain, it still needs two other parts to be useful. One of them is the cerebellum. The cerebellum helps us stay balanced. Without it, we wouldn’t be able to stand straight! That leads us to the last part of the brain, the medulla. The medulla, or brainstem, controls involuntary muscles. For example, it keeps your heart beating and your lungs filling up with air. But this rather tube-like section of the brain has another job. It brings electrical messages that were sent by nerves around the body to the brain, a process you will learn about in the next paragraph.
We’ve all been told that the brain controls everything; Your arms, your legs, your torso, etc. But how exactly does the brain do this? Well, the answer is with nerves. We have over 1 trillion of these long, thin strands spread throughout our body. Their main job is to carry messages to and fro the brain. To do this, though, there are two types of them in our body. One of them is called sensory nerves. This specific type of nerve is in charge of sending messages to the brain from the five senses. For example, if you touch something hot, the sensory nerves will send a message to the brain. But sensory nerves don’t make you draw back your hand. That is the job of the motor nerves. They take messages from the brain and send them to different parts of your body. But when these two types of nerves deliver messages, they are never delivered directly to the brain or body, but through the spinal cord. The spinal cord, an extremely long nerve that runs down your back, takes messages from sensory nerves and sends them to the brain and takes messages from the brain to send them to the motor nerves. But how exactly do nerves send messages around the body? Most of the work is done by neurons. Nerves are made of neurons, which consist of three major parts. One of them is a synapse. A synapse is a structure that allows a message pass from a neuron to another. After that, it goes through dendrites, which brings the message to the cell body. After that, axons take that message away from the cell body and to the next neuron. Well, now you know how far a message has to go for you to move a finger!
The most incredible part of the nervous system is how fast it is. A small electrical pulse, or message, has to travel through trillions of dendrites and axons in much less than a second for us to react to different situations. Next time you walk, talk, or do any movement, think about this powerful, amazing system and what you would do without it!
In conclusion, the human body has many systems that each work hard to do specific jobs to benefit our bodies, but they also work together safely to ensure our well-being. The skeletal system provides us support, protection and structure while the muscular system allows us to move, breathe, and digest food. The circulatory system transports oxygen and nutrients to the cells of our body while getting rid of waste products and the respiratory system swaps out the oxygen and carbon dioxide. Finally, the digestive system converts food into energy while the nervous system uses that energy to make decisions and maintain memories. I appreciate the time you took to read these essays and hope that you learned something valuable. So the next time you move a muscle or take in a breath, I hope you’ll think about how impressive our human body really is!
Works Cited
- "Biology for Kids." Ducksters. N.p., n.d. Web. 29 Mar. 2016.
- "Biology for Kids The Human Brain." Ducksters. N.p., n.d. Web. 29 Mar. 2016.
- Blake, Chris. "Four Main Parts of a Skeletal System." EHow. Demand Media, n.d. Web. 16 Mar. 2016.
- "Blood." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Blood." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Bolus (digestion)." Wikipedia. Wikimedia Foundation, n.d. Web. 29 Mar. 2016.
- "Bones, Muscles, and Joints." Bones, Muscles, and Joints. N.p., n.d. Web. 16 Mar. 2016.
- "Bones, Muscles, and Joints." KidsHealth - the Web's Most Visited Site about Children's Health. The Nemours Foundation, n.d. Web. 16 Mar. 2016.
- "Brain: Nervous System." -- Kids Encyclopedia. N.p., n.d. Web. 29 Mar. 2016.
- "Circulatory System - By KidsBiology.com." KidsBiology.com. N.p., n.d. Web. 29 Mar. 2016.
- "The Circulatory System." N.p., n.d. Web. 29 Mar. 2016.
- "Definition: Bronchial Tubes." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Definition: Pancreas." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "A Description of Tendons, Ligaments and Muscles." LIVESTRONG.COM. LIVESTRONG.COM, 02 June 2015. Web. 29 Mar. 2016.
- Dictionary.com. Dictionary.com, n.d. Web. 29 Mar. 2016.
- "Digestive System Facts for Kids - Stomach, Intestines, Saliva, Esophagus." Science Kids. N.p., n.d. Web. 29 Mar. 2016.
- "Digestive System." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Digestive System." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Five Senses: Facts." (Science Trek: Idaho Public Television). N.p., n.d. Web. 29 Mar. 2016.
- "Follow Your Food!" National Geographic Kids. N.p., n.d. Web. 29 Mar. 2016.
- "Fun Lung Facts for Kids - Interesting Facts about Lungs." Science Kids. N.p., n.d. Web. 29 Mar. 2016.
- "Fun Muscle Facts for Kids - Interesting Information about Human Muscles." Fun Muscle Facts for Kids - Interesting Information about Human Muscles. N.p., n.d. Web. 29 Mar. 2016.
- "Gallbladder." InnerBody. N.p., n.d. Web. 29 Mar. 2016.
- "Gas Exchange." AboutKidsHealth. N.p., n.d. Web. 29 Mar. 2016.
- "Glossary." Hillendale Health. N.p., n.d. Web. 29 Mar. 2016.
- "Heart and Circulatory System." KidsHealth - the Web's Most Visited Site about Children's Health. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Heart and Circulatory System." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "How Bones Work." HowStuffWorks. N.p., 10 Feb. 2009. Web. 16 Mar. 2016.
- "How Bones Work." HowStuffWorks. N.p., 10 Feb. 2009. Web. 16 Mar. 2016.
- "How Does the Circulatory System Work? - Biology | Mocomi Kids." Mocomi Kids. N.p., 21 Aug. 2012. Web. 29 Mar. 2016.
- "Kids' Health - Topics - Blood - We Can't Live without It!" Kids' Health. N.p., n.d. Web. 29 Mar. 2016.
- "Kids' Health - Topics - Your Lungs." Kids' Health. N.p., n.d. Web. 29 Mar. 2016.
- "Kids Research Express." : Larynx. N.p., n.d. Web. 29 Mar. 2016.
- Kids.Net.Au. N.p., n.d. Web. 16 Mar. 2016.
- "Laryngitis." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Larynx." Facts for Kids. N.p., n.d. Web. 29 Mar. 2016.
- "Learn about Your Joints - Science for Kids." Science for Kids. N.p., 22 Apr. 2015. Web. 16 Mar. 2016.
- "Left Atrium." MedicineNet. N.p., n.d. Web. 29 Mar. 2016.
- "Left Ventricle." MedicineNet. N.p., n.d. Web. 29 Mar. 2016.
- "Ligaments and Tendons: What's the Diff?" RSS. N.p., n.d. Web. 16 Mar. 2016.
- "Ligaments and Tendons: What's the Diff?" RSS. N.p., n.d. Web. 16 Mar. 2016.
- "Lungs and Respiratory System." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- Makemegenius. "The Nervous System- Animation-Video for Kids -from Www.makemegenius.com." YouTube. YouTube, 28 Feb. 2012. Web. 29 Mar. 2016.
- "Muscles - By KidsBiology.com." Muscles - By KidsBiology.com. N.p., n.d. Web. 29 Mar. 2016.
- "The Muscular System Makes Movement Possible." (n.d.): n. pag. ClassZone. Web.
- "MUSCULAR SYSTEM." MUSCULAR SYSTEM. N.p., n.d. Web. 16 Mar. 2016.
- "MUSCULAR SYSTEM." MUSCULAR SYSTEM. N.p., n.d. Web. 29 Mar. 2016.
- "The Muscular System." Prezi. N.p., n.d. Web.
- "The Muscular System." Prezi.com. N.p., n.d. Web. 16 Mar. 2016.
- "My Spinal Cord - the Facts." Spinal Hub. N.p., n.d. Web.
- "Neuroscience For Kids." N.p., n.d. Web. 29 Mar. 2016.
- "NIAMS Kids Pages." Healthy Muscles Matter. N.p., n.d. Web. 29 Mar. 2016.
- "Pancreatic Enzymes - Pancreatic Cancer Action Network." Pancreatic Cancer Action Network. N.p., n.d. Web. 29 Mar. 2016.
- "Rectum and Anus." Kidport. N.p., n.d. Web. 29 Mar. 2016.
- "Right Atrium." MedicineNet. N.p., n.d. Web. 29 Mar. 2016.
- "Right Ventricle." MedicineNet. N.p., n.d. Web. 29 Mar. 2016.
- "The Royal Children's Hospital Melbourne." Kids Health Info : Voice Disorders. N.p., n.d. Web. 29 Mar. 2016.
- "The Skeletal System." Human-kinetics. N.p., n.d. Web. 16 Mar. 2016.
- "Structure of Bone." Bone Structure. N.p., n.d. Web. 16 Mar. 2016.
- "Study.com -." Study.com. N.p., n.d. Web. 16 Mar. 2016.
- "Study.com -." Study.com. N.p., n.d. Web. 16 Mar. 2016.
- "Study.com -." Study.com. N.p., n.d. Web. 16 Mar. 2016.
- "Villi." Facts for Kids. N.p., n.d. Web. 29 Mar. 2016.
- "What Are Bones?" Kids' Health. N.p., n.d. Web. 16 Mar. 2016.
- "What Are Ligaments?" WiseGEEK. N.p., n.d. Web. 16 Mar. 2016.
- "What Are Ligaments?" WiseGEEK. N.p., n.d. Web. 16 Mar. 2016.
- "What Are Muscles?" Kids' Health. N.p., n.d. Web. 29 Mar. 2016.
- "What Is Mechanical Digestion?" WiseGEEK. N.p., n.d. Web. 29 Mar. 2016.
- "What Is Peristalsis?" WiseGEEK. N.p., n.d. Web. 29 Mar. 2016.
- "What Is the Function of Digestive Juices?" Innovateus. N.p., n.d. Web. 29 Mar. 2016.
- "What Is the Nervous System?" Kids' Health. N.p., n.d. Web. 29 Mar. 2016.
- "What's Blood?" KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- Wikipedia. Wikimedia Foundation, n.d. Web. 29 Mar. 2016.
- "Word! Bone Marrow." KidsHealth - the Web's Most Visited Site about Children's Health. The Nemours Foundation, n.d. Web. 16 Mar. 2016.
- "Word! Cartilage." KidsHealth - the Web's Most Visited Site about Children's Health. The Nemours Foundation, n.d. Web. 16 Mar. 2016.
- "Word! Cerebellum." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Your Bones." KidsHealth - the Web's Most Visited Site about Children's Health. The Nemours Foundation, n.d. Web. 16 Mar. 2016.
- "Your Brain & Nervous System." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Your Digestive System." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Your Heart & Circulatory System." KidsHealth - the Web's Most Visited Site about Children's Health. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Your Heart & Circulatory System." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Your Liver." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.
- "Your Lungs & Respiratory System." KidsHealth. The Nemours Foundation, n.d. Web. 29 Mar. 2016.