Introduction to the Skeleton - Video Tutorials & Practice Problems
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concept
Skeletal System
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Hello and welcome. It's now time to learn about the skeleton. Now, the skeletal system is gonna be the bones, the cartilages, the joints and the ligaments of the body. But in this unit, we are really gonna focus in and learn those bones. We're gonna start off just by saying that there are 206 named bones in the body and we are gonna learn the names. But that number 206 that's a number you should remember. That's a really easy test question to ask. And if you remember 206 it's a really easy test question to get right. The number 206 though, it's a little bit more of an estimate. Really, we're gonna say that exact number varies by age and by age, it can vary a lot. You're born with way more than 206 bones, you're born with well over 300 bones. And as the skeleton grows and develops, some of those smaller bones grow and fuse together to make the larger bones of the adult skeleton. But it also varies in adults by individual. Some people just have more bones than other people, sometimes those smaller bones will fuse together in one person and they'll remain separate bones in another person, or sometimes small bones will develop in one person that don't develop in another person. That's especially true for the sesamoid bones that are sometimes in people's hands and feet. And then finally, some people develop bones like an extra set of ribs or an extra vertebrae. Now, that's a little bit more rare, but that's a part of normal human variation. And it really means that that 206 while you should remember that number, it's a little bit more of an estimate. All right, we're gonna break this 206 bones up into two major categories. The first category is gonna be the Axio skeleton. Your axial skeleton is gonna be used your skull, your spinal column and your ribs. And by that, I'm really meaning the rib cage, including the sternum. We can look over here at our anatomical model. We see an anatomical model with showing the full skeleton. And you can see in blue that axial skeleton that axial skeleton being the skull, the rib cage and the spinal column, including the sacrum down there at the bottom and the axial skeleton. Well, you can see it goes right down the middle axis of the body. All right, that axial skeleton is there to provide structure for the body, your body, the core of your body has its shape because of those bones but it's also doing a lot of protection for internal organs, the skull, the rib cage and the spinal column all have very sensitive organs inside of them that they are protecting. All right, the second large group of bones that we're gonna learn is gonna be the appendicular skeleton, appendicular skeleton, referring to your appendages, your arms and legs. So that's gonna be your limbs plus the pectoral and pelvic girdles. Now, you may not have heard of the girdles before a girdle is just something that surrounds something or binds something else. So as we look over at our anatomical model here, well, we can, again, we can see the bo bones of the arms and legs. We see the uh bones in the arms and legs there. But then we also have these girdles and that's gonna be things like the shoulder blade and the collar bones up there and the hip bones or the coxal bones down here. Those girdles attach the arms and legs to the axial skeleton. All right, the appendicular skeleton. It is really there to provide movement. This is how you get around in the world. All right. Now, I just wanna again, go back to this number 206 206. Sounds like a lot of bones to learn. It is, but don't worry too much. It's not actually 206 names of bones that you have to learn. For example, there's 80 bones in the axial skeleton, but 24 of those are ribs and another 24 of those are vertebrae. So that's 48 bones. That's more than half the bones in the axial skeleton right there. And we're not gonna learn individual names from each one of those. We're gonna learn to put them in groups. Now, similarly, for the appendicular skeleton, we have 100 and 26 bones, but every single one of th those bones has a right and left so we can cut that number right in half, right away. There's also groups of things like we're not gonna learn an individual name for every finger or toe bone. We learn to put them into groups. Now to muck it up a little bit, we are gonna learn some major features on some bones, some of the lumps and the bumps of the bones and that's gonna bump that number of things. You gotta learn it back up a little bit, but don't worry, we'll get you there. Now, finally, I just like to say when we're learning the skeleton this more than any other unit. In this course, we're learning about the human body and you have a human body, you can feel most of your bones. So as you learn the bones, figure out how they fit in your body, feel your own bones. As you learn about a lump or a bump of a bone, feel it find out where it is, it is not cheating on a test to take a second and feel a bone in your leg or in your arm and make sure that what you're seeing on the page is matching up to what you feel in your body. All right with that. Let's go learn some bonds.
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Problem
Problem
Identify which answer correctly distinguishes between the axial and appendicular skeleton.
