The human skeletal system forms the structural framework of the body, providing support, protection, and shape. It consists of 206 bones organized into the axial and appendicular skeleton. Along with cartilage, ligaments, and joints, the skeletal system facilitates movement and protects vital organs. In this article, the definition of the skeletal system, skeletal system anatomy, and the physiology of the skeletal system are discussed. The Human Skeletal System is a topic of the chapter Locomotion And Movement in Biology.
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In humans, the skeletal system forms one of the most complex structures or frameworks of bones and connective tissues functioning for structuring, protection, and mobility. The human adult skeleton is composed of 206 bones connected by a system of joints, yet held together with cardiovascular, cartilaginous, ligamentary, and tendinous parts.
It supports the body to take shape and maintain posture, protects vital organs like the brain, heart, and lungs and provides for movement via the articulation of bones and the associated action of bones and muscles. It is also relevant to the foremost physiological processes of human beings, offering storage for minerals and producing blood cells inside the bone marrow.
The structure is discussed below-
Adult vs. Newborn Skeletal System: Whereas an adult has 206 bones, in a newborn it is about 270 bones. With increasing maturity, some of the bones fuse and hence the number decreases.
Simple Classification of Bones: The bones can be simply classified into four major groups by their shapes, long bones, for example, femur, and short bones, for example. carpals, flat bones, for example. skull, and irregular bones, for example. vertebrae.
The components are discussed below-
The components of the axial skeleton are:
Skull
This is made up of 22 bones, all together, protecting the brain, and generally forming the structure of the face.
Vertebral column
This is composed of 33 vertebrae, each of which supports the spinal cord a provides protection. These could be grouped into cervical-7, thoracic-12, lumbar-5, sacral-5 fused into the, and coccygeal-4 fused into the coccyx.
Rib cage
This structure is composed of 24 ribs in 12 pairs and the sternum, protects the heart and lungs and supports respiration or breathing.
The components of the appendicular skeleton are:
Pectoral girdle
This is made of the clavicles and scapulae. These bones serve to support the limbs of the upper part of the body, hence making wide-ranging movements at the shoulder possible.
Pelvic girdle
The hip bones are created by the ilium, ischium, and pubis. These bones convey the weight from the upper body to the lower extremities while on the same note serving to protect the pelvic organs.
Limbs
The upper limbs consisting of arms, forearms, wrists and hands and the lower limbs consisting of thighs, legs, ankles, and feet are made up of long and short bones that offer locomotion and contact with the environment
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The functions are discussed below-
The skeleton provides a great framework that helps to support the shape and structure of the body. Since the bones are the chief constituent structure of the body, they are easily able to provide support against the force of gravity and bear other external forces upon it.
The skull covers, overlays, and protects one of the most important organs in the human body, the brain, against damage.
The protective function of the rib cage shields from direct physical trauma heart and lungs—key molecular structures to cardiovascular and respiratory functions.
The skeletal system makes movements and locomotions possible through its interaction with the muscular system. More precisely, bones are attachment sites for muscles; when these muscles contract, they will pull on the bones, generating movement at joints.
Bones act as a storage site for several crucial minerals, primarily calcium and phosphorus, both of which are critical to many bodily functions in general. This mineral content might then be resorbed back into the bloodstream when required and therefore help in the maintenance of mineral balance and metabolism.
The process of hematopoiesis occurs within the red bone marrow in some bones. It is the area where blood cells are formed. Every day, millions of red blood cells are produced by this process for carrying oxygen, many white blood cells for immune defence, and thousands of platelets required for blood clotting
Also Read:
Ribs and Rib Cage | Vertebral Column |
List of 206 Bones in Body | Pectoral Girdle |
Axial Skeleton System | Appendicular Skeleton System |
The important roles played by the human skeleton would include serving to structurally support and give form to the body, protect vital organs, facilitate motion via the joints and attach to the muscles, act as a store of essential minerals like calcium and phosphorus, and produce blood cells within the bone marrow itself.
There are 206 bones in the human adult. At birth, there are about 270 bones, but some of them fuse during growth and hence bring down this number in adults.
Axial skeleton incorporates the bones of the skull and vertebral column and case; it mainly serves to support and protect the central nervous system and thoracic organs. The appendicular skeleton consists of the pectoral girdle, pelvic girdle, and bones of limbs. One of the main functions is movement and interaction with the environment.
It is a bone disorder whereby the bone weakens and gets very prone to fracture. This includes its prevention by a healthy diet rich in calcium and Vitamin D, performing weight-bearing exercises regularly, refraining from smoking and excessive consumption of alcohol, and even medication if a doctor advises.
Types of joints in the human body include:
Ball-and-Socket Joints: Allow rotational movement. Example: shoulder, hip.
Hinge Joints: Allow bending and straightening. Example: elbow, knee.
Pivot Joints: Allow rotation around a single axis. Example: neck.
Saddle Joints: Allow for back-and-forth and side-to-side movements. Example: thumb.
Plane Joints: These allow gliding movements; for example, that between the tarsal bones of the foot.
Condyloid Joints: This allows motion but no rotation; for example, that at the wrist.
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