Where is compact bone found in the body?
Compact bone is the denser, stronger of the two types of bone tissue ((Figure)). It can be found under the periosteum and in the diaphyses of long bones, where it provides support and protection. The microscopic structural unit of compact bone is called an osteon, or Haversian system.
How do you identify compact bone?
Compact bone consists of outer and inner sheets of lamellar bone (not seen here) and Haversian systems, shown here, that run parallel to the long axis of bones. Begin by identifying the concentric rings of lamellar bone that surround a Haversian canal.
What is compact and spongy bone?
Compact bone tissue is composed of osteons and forms the external layer of all bones. Spongy bone tissue is composed of trabeculae and forms the inner part of all bones.
What are osteocytes Class 9?
Osteocyte, a cell that lies within the substance of fully formed bone. It occupies a small chamber called a lacuna, which is contained in the calcified matrix of bone. Osteocytes derive from osteoblasts, or bone-forming cells, and are essentially osteoblasts surrounded by the products they secreted.
What do osteocytes do in bone remodeling?
Bone remodeling has important roles in the functions of bone tissues, such as supporting the body and mineral storage. Osteocytes, which are the most abundant cells in bone tissues, detect the mechanical loading and regulate both bone formation by osteoblasts and bone resorption by osteoclasts.
How do osteocytes communicate?
In summary, osteocytes communicate with each other and cells within the osteoblastic lineage (i.e. osteoblasts and lining cells) by direct cellular contact via gap junctional signaling and by paracrine signaling.
What are two things that osteoblasts need to stay alive?
Components that are essential for osteoblast bone formation include mesenchymal stem cells (osteoblast precursor) and blood vessels that supply oxygen and nutrients for bone formation.
Do osteoblasts eventually become osteocytes?
Osteoblasts (bone forming cells) are of mesenchymal origin, secrete non-mineralized bone matrix (osteoid), and finally become incorporated as osteocytes in mineralized bone matrix. In humans, osteocytes can live long.
How do osteoblasts make new bone?
4.2. Osteoblasts are the bone cells derived from osteochondral progenitor cells that form the bone through a process called ossification. Osteoblasts result in the formation of new layers of bone by producing a matrix that covers the older bone surface.
What does bone originally start as?
Bones begin life as cartilage. The process of hardening cartilage into bone is called ossification. Ossification is achieved by bone-forming cells called osteoblasts (osteo- means “bone” in Greek).