Bone Tissue and Skeletal System Functions

The skeletal system is comprised of multiple tissues working together, including bone, cartilage, dense connective tissue, epithelium, adipose tissue, and nervous tissue.

The skeletal system provides support for the body, acting as a framework for muscles and organs.

Bones play a crucial role in movement by providing attachment points for muscles. When muscles contract, they pull on bones, generating movement.

Bone tissue stores essential minerals like calcium and phosphorus, which can be released into the bloodstream as needed.

Bone tissue contains red bone marrow, where blood cells are produced. This process is called hematopoiesis.

A double layer of connective tissue found on the surface of most cartilage, providing blood and nerve supply.

The outer layer of the perichondrium, composed of dense irregular connective tissue and containing fibroblasts.

The inner layer of the perichondrium, containing chondroblasts and osteochondral progenitor cells, which are responsible for producing new cartilage.

The type of cartilage that covers the ends of bones in joints, lacking a perichondrium.

Articular cartilage lacks a perichondrium, meaning it receives nutrients and oxygen from the underlying bone.

A type of connective tissue that is characterized by its high water content and resilience, allowing it to withstand pressure and return to its original shape. It is found in various parts of the body, particularly in joints.

A key component of cartilage that contributes to its water content. It is a type of molecule that traps water, which in turn provides resilience and shock absorption.

The three main types of cartilage are hyaline, elastic, and fibrocartilage. Each type is defined by a different composition of protein fibers (collagen and/or elastic) and varying amounts of ground substance, leading to unique properties and functions.

Cartilage is avascular, meaning it lacks blood vessels. This unique characteristic makes it slow to heal after injury, as nutrients and waste removal are limited to diffusion from surrounding tissues.

Osteoblasts are cells responsible for building bone matrix, both the organic and inorganic components. They produce collagen fibers and proteoglycans, packaging them into vesicles for release into the extracellular space via exocytosis.

The organic component provides flexibility and strength to bone, while the inorganic component provides hardness and compressive strength. This combination allows bones to withstand stress and bending.

Osteoblasts produce matrix vesicles, which are small sacs filled with calcium and phosphate that are pinched off from the osteoblast cell membrane. These vesicles contribute to the mineral component of bone.

The organic component of bone matrix is comprised of collagen fibers and proteoglycans, which are responsible for providing the flexible strength of bone. They act like a framework for the mineral component.

The inorganic component of bone matrix is primarily composed of calcium phosphate crystals, which give bone its hardness and compressive strength. These are essential for supporting the weight of the body and resisting crushing forces.