Where is compact bone the thickest

Osteoclasts are capable of demineralizing bone. Bone marrow is located in the medullary marrow cavity of long bones and in some spongy bones. There are 2 kinds of marrow. Red marrow exists in the bones of infants and children. It is called red because it contains a large number of red blood cells. In adults the red marrow is replaced by yellow marrow. It is called yellow because it contains a large proportion of fat cells.

Yellow marrow decreases its ability to form new red blood cells. However, not all adult bones contain yellow marrow. The following bones continue to contain red marrow and produce red blood cells:. The skeleton is divided into 2 sections: the axial and appendicular sections Figure 5. The axial skeleton includes the skull, spine, ribcage, and sacrum and is indicated in blue in the figure below. The appendicular skeleton is indicated with red labels. Improve this page Learn More.

Skip to main content. Module Overview of Body Systems. When you think of the skeleton, what comes to mind? Hard, dry bones, right? You can thank artistic conditioning in kindergarten for that one.

The thing is, bones may be hard on the outside, but on the inside they're a smorgasbord of vessels, nerves, and other things. I may just blow your mind with this post. Compact bone is dense bone tissue found on the outside of a bone. Basically, in kindergarten when you drew skeletons, you were drawing compact bone. Compact bone is enclosed, except where it's covered by articular cartilage, and is covered by the periosteum.

The periosteum is a thick fibrous membrane covering the entire surface of a bone and serving as an attachment for muscles and tendons. Vessels pass from the periosteum through pores into the compact bone and run through canals found throughout the tissue.

Spongy bone is on the interior of a bone and consists of slender fibers and lamellae—layers of bony tissue—that join to form a reticular structure. Spongy bone is supplied by fewer and larger vessels than compact bone.

These vessels perforate the outer compact layer and are distributed into the spongy portion of bone, which is filled with marrow. Bone marrow is tissue found in long bones, like the femur, that contains stem cells. Osteons are interesting little things. Osteons are structural units of compact bone.

Each osteon consists of a central canal, which contains nerve filaments and one or two blood vessels, surrounded by lamellae. Which bone is mostly made of cortical bone tissue?

What term is given to the end of long bones? What is an example of compact bone? Do all bones have compact and spongy bone? What are the thin plates forming spongy bone called?

Is the nasal bone a flat bone? Which bone is the longest and strongest bone in the human body? Why is compact bone so strong? What type of bone growth does a 40 year old male experience? What type of bone growth do you think a year-old male experiences? What are bone cavities called? Where is the softest bone located? Which is the most powerful bone in our body? What are bone forming cells called?

What cushions the ends of bones at their joints? Is cortical bone brittle? How is bone created? Are joints movable? Still, most doctors feel that the benefits of bisphosphonates more than outweigh the risk; the medical professional has to weigh the benefits and risks on a case-by-case basis. Bisphosphonate treatment can reduce the overall risk of deformities or fractures, which in turn reduces the risk of surgical repair and its associated risks and complications. The spongy bone and medullary cavity receive nourishment from arteries that pass through the compact bone.

The osteocytes in spongy bone are nourished by blood vessels of the periosteum that penetrate spongy bone and blood that circulates in the marrow cavities. As the blood passes through the marrow cavities, it is collected by veins, which then pass out of the bone through the foramina. In addition to the blood vessels, nerves follow the same paths into the bone where they tend to concentrate in the more metabolically active regions of the bone.

The nerves sense pain, and it appears the nerves also play roles in regulating blood supplies and in bone growth, hence their concentrations in metabolically active sites of the bone. Watch this video to see the microscopic features of a bone. A hollow medullary cavity filled with yellow marrow runs the length of the diaphysis of a long bone. The walls of the diaphysis are compact bone. The epiphyses, which are wider sections at each end of a long bone, are filled with spongy bone and red marrow.

The epiphyseal plate, a layer of hyaline cartilage, is replaced by osseous tissue as the organ grows in length. The medullary cavity has a delicate membranous lining called the endosteum. The outer surface of bone, except in regions covered with articular cartilage, is covered with a fibrous membrane called the periosteum. Flat bones consist of two layers of compact bone surrounding a layer of spongy bone. Bone markings depend on the function and location of bones.

Articulations are places where two bones meet. Projections stick out from the surface of the bone and provide attachment points for tendons and ligaments. Holes are openings or depressions in the bones. Bone matrix consists of collagen fibers and organic ground substance, primarily hydroxyapatite formed from calcium salts. Osteogenic cells develop into osteoblasts. Osteoblasts are cells that make new bone. They become osteocytes, the cells of mature bone, when they get trapped in the matrix.

Osteoclasts engage in bone resorption. Compact bone is dense and composed of osteons, while spongy bone is less dense and made up of trabeculae.

Blood vessels and nerves enter the bone through the nutrient foramina to nourish and innervate bones. Which of the following are only found in cancellous bone? The area of a bone where the nutrient foramen passes forms what kind of bone marking?

If the articular cartilage at the end of one of your long bones were to degenerate, what symptoms do you think you would experience? If the articular cartilage at the end of one of your long bones were to deteriorate, which is actually what happens in osteoarthritis, you would experience joint pain at the end of that bone and limitation of motion at that joint because there would be no cartilage to reduce friction between adjacent bones and there would be no cartilage to act as a shock absorber.

In what ways is the structural makeup of compact and spongy bone well suited to their respective functions? The densely packed concentric rings of matrix in compact bone are ideal for resisting compressive forces, which is the function of compact bone. The open spaces of the trabeculated network of spongy bone allow spongy bone to support shifts in weight distribution, which is the function of spongy bone.

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