The Skeletal System

The Skeletal System

Introduction

Skeletal System

The skeletal system in humans is composed of 206 bones, which are connected by tendons and ligaments. The skeletal system supports soft tissues; it produces blood cells, stores minerals and supports movements of the body. The skeletal system can be divided into axial skeleton and appendicular skeleton. Axial skeleton consists of 80 bones and includes the rib cage, the vertebral column, and the skull. Axial skeleton maintains upright posture and transmits weight from upper body to lower extremities. The appendicular skeleton consists of 126 bones and includes the upper limbs, the lower limbs, pectoral girdles, and the pelvic girdles. This helps in locomotion (Applegate, 2010). The skeleton system has following basic functions:

The skeleton supports the body.

The skeleton permits movement.

The skeleton protects the brain and other vital organs.

The skeleton supports haematopoiesis.

The skeleton stores calcium and iron (Tözeren, 2000).

Discussion

Bones

Bones are made of hard materials, which give strength and allow movements and provide stability to human body. These bones contain bone marrow, which supports haematopoiesis. There are 206 bones. Bone formation is supported by fibroblasts, which secrete collagen fibers and then cartilaginous material is deposited between these fibers, which ossified to form mature bone. Bone grows form the epiphyseal line and is controlled by growth hormone. The calcium deposition is facilitated by testosterone, estrogen, alkaline phosphatase and mechanical stress (Applegate, 2010).Bone absorption is facilitated by parathormone and inactivity. Bone consists of following cells as:

Osteoblasts

They facilitate bone building and repairing.

Osteocytes

These are the mature bone cells present in the bone matrix.

Osteoclasts

They cause bone reabsorption.

Bones also contain periosteum, which is dense fibrous membrane around the bone and contains blood vessels. It support bone cell survival. Following are the types of bones:

Compact Bone

Compact bone are dense and contains Haversian systems, which includes:

Lamellae, which ...