General Overview
The human skeletal system consists of 206 bones in adulthood, though infants are born with around 270 bones. Over time, some bones fuse, forming the stable adult skeleton. In addition to bones, the system includes cartilage for cushioning joints, ligaments for connecting bones, and tendons for attaching muscles to bones.
Axial vs. Appendicular Skeleton
The skeleton is divided into two primary parts: the axial skeleton and the appendicular skeleton.
Axial Skeleton:
The axial skeleton forms the central framework of the body, consisting of 80 bones.
It includes the skull, vertebral column, and rib cage.
Functions include protecting vital organs like the brain, heart, and lungs, and supporting posture.
Appendicular Skeleton:
The appendicular skeleton consists of 126 bones, including those in the arms, legs, shoulders, and pelvis.
It facilitates movement and interaction with the environment by providing attachment points for muscles.
Functions of the Skeletal System
The skeletal system performs several essential functions, making it indispensable to overall health and mobility:
Support:
It provides structural support, maintaining the body’s shape and posture.
Protection:
The skeleton safeguards delicate organs, such as the brain (protected by the skull), the spinal cord (encased in the vertebral column), and the heart and lungs (shielded by the rib cage).
Movement:
Bones act as levers, and joints function as pivots, allowing muscles to generate movement.
Mineral Storage:
Bones serve as reservoirs for essential minerals, including calcium and phosphorus, which can be released into the bloodstream when needed.
Blood Cell Production:
The bone marrow, particularly in flat bones like the sternum and pelvis, produces red and white blood cells and platelets, a process known as hematopoiesis.
Energy Storage:
Yellow marrow, found in the central cavities of long bones, stores lipids as an energy reserve.
Endocrine Regulation:
Bones release hormones such as osteocalcin, which helps regulate blood sugar levels and fat deposition.
https://my.clevelandclinic.org/health/body/21048-skeletal-system Assessed and Endorsed by the MedReport Medical Review Board