Skelës

Skelës refers to the internal framework that supports the bodies of many organisms, most notably vertebrates. In humans and other mammals it is an endoskeleton composed of bone and cartilage, organized into two major subsystems: the axial skeleton, which includes the skull, spine, and rib cage, and the appendicular skeleton, which includes the limbs and their girdles. The term is used to denote the skeleton in general.

Bones provide shape and protection; joints enable movement; bone marrow produces blood cells; the skeleton also stores minerals such as calcium and phosphorus. The axial skeleton protects the brain, spinal cord, heart, and lungs, while the appendicular skeleton supports limbs and transfers forces during movement.

Bones come in several shapes: long bones (such as the femur), short bones (carpals), flat bones (ribs and skull bones), and irregular bones (vertebrae). They are organized into compact bone on the outside and spongy bone inside, with bone marrow housed within certain bones.

Cartilage provides cushioning at joints, while ligaments connect bones across joints. Joints, or articulations, allow varying degrees of movement depending on their type.

Development and remodeling: the skeleton forms from embryonic cartilage or fibrous membranes and grows through childhood and adolescence. After growth, bones continuously remodel in response to stress, with cells such as osteoblasts and osteoclasts maintaining strength and mineral balance.

Functions extend beyond support and protection. The skeleton plays a role in hematopoiesis, mineral homeostasis, and endocrine signaling through bone-derived factors. Abnormalities include fractures, osteoporosis, and arthritis, which can affect mobility and health.