- Bone is a living tissue.
- They change its structure due to the the stresses, when it applied on it.
- Bone consists of cells, fibers, and matrix.
- It is hard due to calcification and possesses a degree of elasticity .
- Bone protect the body; the skull and vertebral column, for example, protect the brain and spinal cord from injury; the sternum and ribs protect the thoracic and abdominal organs.
- It serves as important storage area for calcium .
- It protects blood-forming bone marrow.
Bones are exist in two forms:
- Compact bone appears like solid mass;
- Spongy bone consists of a branching network of trabeculae. The trabeculae arranged in such a way that help the bone from stress and strain.
They may be classified according to their shape.
- Long bones
- Short bones
- Flat bones
- Irregular bones
- Sesamoid bones
Long bones are present in the limbs such as the humerus, femur, metacarpals, metatarsals, and phalanges. The length of long bone is greater than their breadth. They have a tubular shaft, the diaphysis, and an epiphysis at each end.
Short bones are those bones that are as wide as they are long. Their essential function is to offer help and steadiness with almost no movement.
Flat bones are thin, flattened, and usually curved. The cranium bones are flat bones.
That aren’t in any of the above three categories are classified as irregular bones. The vertebrae and a few of the bones within the skull are irregular bones.
Sesamoid bones are small round or oval shaped bones. That are present within certain tendons. Typically there are five sesamoid bones in each hand; two at the metacarpophalangeal (MCP) joint of the thumb, one at the interphalangeal (IP) joint of the thumb, one at the MCP joint of the index on the radial side, and one at the MCP joint of the small finger on the ulnar side.
Cartilage is a crucial structural part of the body. It is a firm tissue but is softer and far more flexible than bone.
Cartilage is (may) an animal tissue found in many areas of the body including:
Joints between bones e.g. the elbows, knees and ankles
- Ends of the ribs
- Between the vertebrae in the spine
- Ears and nose
- Bronchial tubes or airways
Cartilage forms from specialized cells called chondrocytes. Chondrocytes produce large amounts of extracellular matrix composed of collagen fibers, proteoglycan, and elastin fibers. There are not any blood vessels in cartilage to provide the chondrocytes with nutrients.
TYPES OF CARTILAGE
In childhood and adolescent, it plays an important role in the growth of long bones.
It has many collagen fibers embedded in small amount of matrix.
Fibrocartilage if damaged it repair itself in a manner similar to fibrous tissue elsewhere.
It has large number of elastic fibers embedded in matrix.
It is flexible.
If damaged repair itself with fibrous tissue.