What is a Skeletal System?
The skeletal system or skeleton is a framework composed of bones and cartilages. Its major function is to give support and protection to the body. The skeleton can be classified into two subgroups –
- Axial skeleton – It consists of the bones of the skull or cranium, ribs, sternum and vertebral column
- Appendicular skeleton – It consists of the bones of the lower and upper limbs
Components of a Skeletal System
The skeletal system consists of bone and cartilage. Humans have approximately 270 bones at the time of birth, which eventually decreases to 206 as we age.
Bone is a rigid, calcified, living, connective tissue that forms the major portion of the skeleton. It typically has an intercellular calcified matrix that contains collagen fibres and various other types of cells like osteoclasts, osteocytes and osteoblasts.
5 Functions of bones in the skeletal system
- Supportive structure for the body
- Protector of important internal organs
- Reservoirs of minerals like phosphorus and calcium
- Levers on muscles and act to produce movement
- Contains blood-producing cells called bone marrow.
Cartilage is an avascular (no blood vessels) form of elastic connective tissue that usually protects the bones at the joints. They are elastic tissue that forms the structure of the nose, ear, bronchial tubes, etc. It is composed of chondrocyte cells that produce and maintain the cartilaginous matrix. This matrix is composed of proteoglycans, glycosaminoglycans, elastic fibres and collagen. In heavy weight-bearing areas, the collagen level is high and the cartilage is almost inextensible. In contrast, in regions where the stress and weight-bearing demands are less, cartilage contains fewer collagen and elastic fibres.
3 Major functions of cartilage
- It supports soft tissues
- It provides a smooth and gliding plane for bone articulation at joints
- It enables the growth and development of long bones
Also Read: Difference between Bone and Cartilage
Five Major Functions of Skeletal System
To sum up the above content, the five major functions of the skeletal system are as follows –
- Support – The bones and cartilages provide the framework to maintain the body shape. Without these skeletal components, the body parts would collapse.
- Protection – The vital function of the skeletal system is to protect the internal organs. The structures like the skull, rib cage and vertebrae protect the brain, lungs and spinal cord respectively.
- Movement – A wider range of body movements is because of the coordinated action of the skeletal system, nervous system and muscles.
- Storage of Minerals – Bones are a reservoir of minerals like phosphorus and calcium. It also plays an important role in calcium metabolism.
- Production of Blood cells – The bone marrow is a site of haematopoiesis where the formation of blood cells takes place.
Apart from these major functions, bones also play a role in endocrine regulation. The bones produce a non-collagenous protein hormone called osteocalcin which regulates cellular responses to insulin stimuli.
Explore: Human Body
Frequently Asked Questions
What are joints?
The sites where two skeletal elements come together are termed joints. The two general categories of joints are synovial joints and solid joints. In synovial joints, the skeletal elements are separated by a cavity, and in solid joints, there is no cavity. Here, the components are held together by connective tissue.
What is a tendon?
Tendon is a high tensile fibrous connective tissue that aids in the connection of bones and muscles. Both tendons and ligaments are composed of collagen. But ligaments help in connecting two bones together.
What is a rib cage?
A rib cage is a cartilaginous and semi-rigid bony structure that surrounds the chest cavity. This encompasses the sternum, vertebral column and ribs. The ribs are connected to the sternum with the help of costal cartilage. The rib cage holds the respiratory muscles and plays a vital role in respiration.
Also Check: Difference between Ligaments and Tendons
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