Bones and cartilages are types of connective tissue in the body. Bones are hard tissue that form the skeletal structure of the body; Cartilages are not as hard and rigid as bones, and present in areas of the body like the ear, nose and joints. In the joints of the body, cartilage covers the ends of the bones and acts as a shock absorber to prevent the ends of bones from rubbing against each other.
edit Differences in Physical structure
The structure of bones is a combination of living and dead cells embedded in a matrix. The outer hard layer of the bone is referred to as compact bone and has few spaces. The internal part of bone also called spongy tissue is porous and harbours the bone marrow and blood vessels. Other tissue found in bone includes endosteum, periosteum and nerves. Bone matrix has organic (mineral) components and inorganic components such as collagen. Bone formation is the result of hardening of this matrix.
Cartilage essentially consists of chondrocyte cells which produces extracellular matrix consisting of collagen fibres, proteoglycan and elastin fibres and different types of cartilage contain these components in different proportions. Cartilage, unlike bones, does not contain blood vessels.
edit Cellular Structure of Bones vs Cartilages
Bone or osseous tissue is made up of osteoblasts, the progenitor cells, which give rise to osteocytes, which are the mature bone cells, and osteoclasts which are large cells that breakdown bone tissue for growth, repair and remodelling. Another type of bone lining cells is present that regulate the movement of calcium and phosphate in and out of the bone.
Cartilage comprises of chondrocytes, produced by precursor cells known as chondroblasts. Chondroblast, produce a dense matrix comprising of collagen and elastin fibres, in which the mature chondrocyte cells are embedded.
edit Cartilage vs Bone Diseases
Main disorders of the bone consists of are osteoporosis, in which the bone mineral density gets reduced, and increases the likelihood of a fracture, osteosarcoma, a cancerous condition of the bone, osteomyelitis, which is an infection of the bone marrow and osteogenesis imperfecta which is a genetic disorder.
Diseases of the cartilage include, osteoarthritis is a condition in which the cartilage gets thinned out resulting in friction between bones, achondroplasia, which leads to dwarfism, costochondritis, which is inflammation of the cartilage in the ribs resulting in chest pain and chondrodystrophies which are a group of diseases due to disturbance in growth of cartilage and subsequent ossification of cartilage.
edit Types of bones and cartilages
Bones are classified into long, short, flat, irregular, sesamoid and sutural bones. Most bones of the limb are long bones characterized by a long shaft and curved structure. Examples include femur, tibia, fibula, humerus, ulna and radius. Short bones are the same in length and width and present in the ankle and wrist. Flat bones are thin and curved and examples include bones of the skull and sternum. Irregular bones are found in the spine and hip region. Sesamoid bones are developed in the tendons, and most commonly found in the palm of the hands and soles of the feet, and in the kneecaps. Sutural bones are very small bones found in the sutures between the cranial bones, and vary in different persons.
Types of cartilage include hyaline cartilage, fibrocartilage and elastic cartilage. Hyaline cartilage is the most abundant of the three types of cartilage. It is found mainly in the bronchial tubes, larynx, nose and trachea, end of long bones and in the embryonic skeleton. It serves to provide structure and smooth movement. Fibrocartilage is a tough form of cartilage found at the site of fractures, intervertebral discs, knee, hip and other joints. Fibrocartilage provides rigidity and structure to the attached structures. Elastic cartilage is more elastic and is present in the external ear, auditory tubes and epiglottis.
edit Differences in Function
Bones perform a variety of functions like protecting the body against mechanical damage, for example the skull protects the brain and the rib cage protects the internal organs and so on; assists in the movement of the body as the skeletal muscles are attached to the bones; provides a framework and shape of the body; stores minerals like calcium and phosphorous; red bone marrow stored in the bones, produces erythrocytes (red blood cells) and leucocytes (white blood cells); and yellow bone marrow which also contains adipose cells is an important reserved for energy.
The main functions of cartilage tissue include reducing friction at the joints, supporting tracheal and bronchial tubes, acting as shock absorbers between vertebrae, maintaining the shape and flexibility of ear, nose and so on.