okay so this is just an overview of the different structures that you need to identify on the bone model um for lab and I want to begin with the two membranes so if you remember the periostium is a membrane that lines the external surface of bone and then we have the end oium that lines every internal surface of bone that we have including canals including um Perforating canals Central canals um spongy bone cavities and triculate everywhere that there's a space inside of the bone is going to be lined with end oium so looking at the bone model our per oium or outermost membrane is going to be this entire whitish gray area and if you remember from lecture that each one of the periostium uh layers is going to have these white extensions coming off of the side and these white extensions that are coming off of the side are called Perforating fibers and these Perforating fibers are there to help adhere the periostium or the outer membrane to the compact bone itself the other membrane is the end oium so if we're looking at the bone model we're going to go towards the medular cavity which is the center which is what you're looking at now and this um area that's shaded in Gray or covered in Gray that's going to represent the end oium so the inner membrane right there uh this bone colored area or yellow area right here that's invading into the spongy bone these are your tulle so the tulle and all these cavities formed in the spongy bone are all lined with an oium and we can also see that we have some blood supply through there as well okay now we can go on to the structures of compact bone and I want to start with um the oion because the oion is the structural and functional unit of bone so if you remember each oion is represented as one entire ring um structure right here so this is one oion this is an oion here's another oion here and another one right there in the center of each oon we have what's called a central Canal or hsan canal and this is where we're going to get our nutrient Supply and nerves coming through um the central Canal or her verion Canal each osteon is made up of additional rings so this particular osteon we see a ring here a ring here ring ring and ring until we hit the central Canal each one of these Rings is called a lame um we have other types of L besides the ones that make up the rings of the oon so if you look here we see that we have some Rings or lines but they're incomplete so what we call these incomplete lamel that reside between the different oons so right in here um we also have some right through here and here these are called interstital lame incomplete lame or intertial laml we also have laml that make up the entire circumference of the bone itself so this is only like a piece cut out of an entire circle of bone um cross-section of bone so we can't see the entire circumference but we can see that over here we have these LEL also shown represented extended and pulled out but each one of these rings that goes along the circumference of the the compact bone those are called circumferential lamel so again just as a review three types of lame the ones that go around the circumference on the outside those are called circumferential the incomplete lame between the different oon those are called interstial lame and then the ones that make up the osteon themselves these Rings we just call lame also you'll probably notice that we have within each Lam these little cavities and I don't know if you can tell but these are actual like holes or indentations I could fit this stick in if it was a little bit smaller um so this is what you call a Lun so they're cavities in which osteocytes reside um that's your M mature bone cell that's going to help help to create and maintain um the ocus tissue in The Matrix um so while this one is represented as a hole or a cavity we have Lun represented in two other ways so these white circle areas or oval areas and these other lamel those would also be considered Lun and then if you look over here we see these dark brown ovals and these are also considered Lun so represented in three different ways um you can also see them down here as like a more circular um structure but all of those are Lune and they all contain um condro sites specifically um that are going to reside in there if you look on some of the lacune we can see these little hairlike or spider- like legs coming off extending off and those are your canu liuli and they're not incredibly well um depicted here but typically their function is to act as tiny little canals that go on to connect other Lune so that the Osteo sites residing inside of the Lun can communicate so they're just little hair light canals the can you luuli and they allow for communication in the event that we need to undergo some bone remodeling um other things that I wanted to point out on this I think that's it there so let's move to this view so we already talked a little bit about um the Perforating f F so these are the Perforating fibers just as a reminder they're extending off of the periosteum um we have canals two types we have ones that are running horizontally is through the bone and those are called Perforating canals or vman's canals and in order not to get your central canal and your vman Canal confused on this um bone model the Perforating Canal runs horizontally and it runs in the same direction as your Perforating fibers so Perforating fibers Perforating Canal all these vertical canals that you see extending along um the long axis of the bone these are your central or hsan canals so this Central or hsan Canal right here it may not make much sense to you until you see the top and if you see the top um we can see the blood vessels and that this oion was cut in half so what we're actually looking at is the central Canal for that structure so this is the one showing you that the function of the central canal and the Perforating canals is to carry all the blood supply and the blood vessels but you can also see it represented in this way in which there are no blood vessels passing um we're still looking at just the canals itself so all the vertical ones are your central or um perversion canals anything that you see that's horizontal is going across or better way to State it is anything that's not vertical um is going to be your Perforating or bulman's canal and I think we've pretty much covered everything um I did mention I believe that the bone marrow resides in this area so this is your spongy bone these are your tracula these bone spicules extending um here urine oium we do have blood supply here in the center not shown here if we continued around um the center right here we would have a medular cavity and this area would have bone marrow um and we also have some bone marrow within the tracula themselves