|LESSON 4: Bone Tissue|
BONE TISSUE & ANATOMY
Bone tissue is a type of connective tissue that contains lots of calcium and phosphorous salts. About 25% of bone tissue is water, another 25% is made up of protein fibers like collagen. The other 50% of bone tissue is a mixture of mineral salts, primarily calcium and phosphorous.
Kinds of Bone Tissue
There are two different kinds of bone tissue: Compact and Spongy bone.
- Is made up of concentric rings of matrix that surround central canals which contain blood vessels.
- Embedded in this bone tissue are small cave-like spaces called lacunae, which are connected to each other through small tunnels called canalicula.
- The lacunae contain osteocytes cells. As just discussed, osteocytes help maintain healthy bone tissue and are involved in the bone remodeling process that will be outlined later in this lesson.
- Looks like an irregular latticework (or sponge) with lots of spaces throughout.
- These spaces are filled with red bone marrow which is the site of hemopoesis or formation of blood cells.
Bones in the body are found in two basic forms, long bones and plates.
Long bones of this kind are hollow on the inside. The inner space is called the medullary cavity. Bones are also covered by two membranes on the outside of the bone is the Periosteum. The inside of the bone, lining the medullary cavity is the Endosteum.
The Epiphysis refers to the end of the bone, and the Diaphysis refers to the main shaft of the bone.
Each Epiphysis is connected to an adjacent bone using a structure called a joint. The ends of each bone are covered with articular cartilage which keeps the ends of the bones from grinding together when moving.