Benskelett

Benskelett, or the bony skeleton, is the rigid framework of mineralized tissue that supports vertebrate bodies. In humans it consists of about 206 bones at adulthood, though the exact number varies with anatomical variation and congenital differences. The skeleton is divided into the axial skeleton (skull, vertebral column, rib cage) and the appendicular skeleton (limbs and girdles).

Bone tissue is a dynamic, living tissue composed of a mineralized matrix, mainly collagen type I and hydroxyapatite, organized into cortical (compact) bone and trabecular (spongy) bone. The cellular component includes osteoblasts (bone-forming), osteocytes (mature bone cells), and osteoclasts (bone-resorbing), which together regulate bone formation, maintenance, and remodeling.

Functions include structural support, protection of internal organs, enablement of movement through joints and attached muscles, and mineral storage (primarily calcium and phosphate). Red bone marrow within certain bones produces blood cells, a process known as hematopoiesis. Bone also participates in endocrine signaling, notably via osteocalcin, which can influence energy metabolism.

Development and growth occur through ossification. Long bones grow in length by endochondral ossification at the growth plates; flat bones form via intramembranous ossification. Throughout life, bone remodeling maintains strength and mineral homeostasis by balanced activity of osteoblasts and osteoclasts.

Clinical relevance includes peak bone mass in early adulthood, age-related bone loss, osteoporosis, and fracture risk. Variation across species and within individuals reflects evolutionary and developmental factors shaping the bony skeleton.