Cells, Tissue, and Organs

Hi, I am Jared. Welcome to Fun Science Demos. Over 150 years ago, scientists used microscopes, just like this one, to look carefully at plants and animals. They would take small pieces of those plants or animals, put them on this glass slide, and look at it under the microscope. And guess what they discovered? They discovered that all plants and animals are made of these tiny little parts that they called cells. And that is the big idea today. All plants and animals are made of cells. And we are going to zoom in and take a closer look at some of those cells. When scientists looked at those plants and animals under the microscope, here are some pictures of what they saw. They saw skin cells. They saw muscle cells. Here is a picture of some bone cells. Now these are some nerve cells. And take a look at that. Those right there, those are blood cells. So scientists found all these different cells. How do they work together and what do they do? Meet my good friend Rachel C. Rachel is the same size as a real human being, but she is not real. She is made of plastic. And she looks a little bit different because we have taken off her skin so we can see inside. Believe it or not, all of us look the same on the inside. And all of these inside parts are made of cells, the same cells we looked at under the microscope. Now scientists call all of these different inside parts organs. And each of these organs has a special job. And each of these organs are also made of the same type of cells. So let us explore these different organs and take a look at what they do. But remember, every cell in our body needs two things. They need food and they need oxygen. So take a deep breath. Well when you breathed in, I breathed in air. Where did that air go? The air went inside these organs. Scientists call these organs the lungs. And what is their job? Their job is to take oxygen from the air and put it into our blood. But how does that oxygen in the blood get to all of our different cells? Well take a look at this. We can pull off the lungs and we find something right here. This organ is a heart. It is about the same size as a closed fist. And what is its job? Well this organ is a pump and it pumps blood to all of the cells in our body. And that blood has oxygen and food. The oxygen comes from the lungs. But where does the food come from? Well when we eat, food travels down our throat, behind the heart, into this organ right here. It is called the stomach. You cannot see all of it because it is covered by the liver, another organ. Your mouth and your stomach make that food smaller and your stomach is connected to this next organ. It is a long tube called the intestines. There is the big intestine and then there is the small intestines. It is hard to see it because it is all bunched up, but the intestine is one long tube. In fact, it is about 20 of these pointers placed end to end. That is really long. The blood takes food from our intestines and moves that to every cell in our body. Now we do not use all the food we eat, so where does that food go? Well it comes out of our body. Remember all of these organs work together to keep all of our cells alive and working. How many cells are they keeping alive and working? Well the human body has a lot of cells. How many? Well through science we have discovered and through the microscope we have discovered that there are not hundreds of cells. There are not millions of cells. There are not billions of cells. There are trillions of cells that make up our human body. That is a lot of cells doing a lot of work. They are little. We can only see them through a microscope, but those little things are really powerful. If you want to learn more about the human body, check out our links in the video description. Science is so cool. The human body is so cool. Thanks for watching.