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Each osteon consists of concentric layers, or lamellae, of compact bone tissue that surround a central canal, the Haversian canal. The Haversian canal contains the bone's blood supplies. The boundary of an osteon is the cement line. Each Haversian canal is surrounded by varying number (5-20) of concentrically arranged lamellae of bone matrix.
The endosteum (pl.: endostea) is a thin vascular membrane of connective tissue that lines the inner surface of the bony tissue that forms the medullary cavity of long bones. [1] [2] This endosteal surface is usually resorbed during long periods of malnutrition, resulting in less cortical thickness. [citation needed]
This joint unites long bones and permits free bone movement and greater mobility. [1] The synovial cavity/joint is filled with synovial fluid . The joint capsule is made up of an outer layer of fibrous membrane, which keeps the bones together structurally, and an inner layer, the synovial membrane , which seals in the synovial fluid.
This is covered by a membrane of connective tissue called the periosteum. Beneath the cortical bone layer is a layer of spongy cancellous bone. Inside this is the medullary cavity which has an inner core of bone marrow, it contains nutrients and help in formation of cells, made up of yellow marrow in the adult and red marrow in the child.
Diagram of a typical long bone showing both cortical (compact) and cancellous (spongy) bone. Haversian canals [i] (sometimes canals of Havers, osteonic canals or central canals) are a series of microscopic tubes in the outermost region of bone called cortical bone. They allow blood vessels and nerves to travel through them to supply the osteocytes.
Cancellous bone or spongy bone, [12] [11] also known as trabecular bone, is the internal tissue of the skeletal bone and is an open cell porous network that follows the material properties of biofoams. [13] [14] Cancellous bone has a higher surface-area-to-volume ratio than cortical bone and it is less dense. This makes it weaker and more flexible.
Connective tissues are made up of cells separated by non-living material, which is called an extracellular matrix. This matrix can be liquid or rigid. For example, blood contains plasma as its matrix and bone's matrix is rigid. Connective tissue gives shape to organs and holds them in place.
The fibrous layer is of dense irregular connective tissue, containing fibroblasts, while the cambium layer is highly cellular containing progenitor cells that develop into osteoblasts. [3] These osteoblasts are responsible for increasing the width of a long bone (the length of a long bone is controlled by the epiphyseal plate ) and the overall ...