Bone Classification and Skeletal Functions

Study Notes

Bone Classification

Long bones: Elongated shape; includes femur and phalanges.
Short bones: Blocky structure; example includes talus in the ankle.
Flat bones: Formed in intramembranous layer; includes skull bones, similar to a sheet cake.
Irregular bones: Numerous projections for muscle attachment; example includes vertebrae.
Sesamoid (round) bones: Form within a tendon; patella (kneecap) is a key example.

Functions of the Skeletal System

Support: Provides attachment points for muscles.
Movement: Works in tandem with the muscular system for mobility.
Protection: Shields vital organs; brain and spinal column receive the highest level of protection, followed by the heart and lungs.
Hemopoiesis: Blood cell production occurs in the bone marrow.
Storage: Stores inorganic salts like calcium carbonate and phosphate, vital for bone strength and bodily functions.

Parts of a Long Bone

Epiphysis: Ends of the bone, categorized as distal and proximal.
Diaphysis: Central shaft of the bone.
Compact bone: Dense structure, encasing the marrow.
Spongy bone: Found in the epiphysis; porous and lighter.
Articular cartilage: Hyaline cartilage covering the joints, facilitating movement.
Periosteum: Connective tissue covering the exterior; allows for diameter growth.
Endosteum: Lining of the inner bone.
Medullary cavity: Hollow inside of long bones.
Trabeculae: Solid portions of spongy bone.
Bone marrow:
- Red marrow: Contains nutrient-rich blood.
- Yellow marrow: Fatty tissue.

Microscopic Structure of Compact Bone

Osteon: Functional unit aligned parallel to the diaphysis, resembling tree rings.
Central canal: Contains blood vessels and nerves.
Perforating canal: Connects osteons via vascular channels.
Osteocyte: Mature bone cell residing in lacunae.
Lacuna: Cavities where osteocytes are located.
Lamellae: Layers of solid matrix forming the bone.
Bone matrix: Provides rigidity and structure to bones.
Canaliculus: Tiny channels linking lacunae and facilitating nutrient exchange.

Cell Types

Stem cells: Undifferentiated cells that can develop into various cell types.
Osteogenic cells: Progenitors destined to become bone cells, specifically osteoblasts or osteoclasts.
Osteoclasts: Specialized cells that break down bone tissue.
Osteoblasts: Cells that form new bone; akin to fibroblasts in bone structure.
Osteocytes: Mature bone cells that maintain the bone matrix from their lacunae.

Bone Development

Intramembranous ossification: Occurs within connective tissue layers; forms broad, flat bones like most skull bones (except mandible).
Endochondral ossification: Begins with a hyaline cartilage model; responsible for the majority of bones in the skeletal system, transforming into mature bone.

Endochondral Ossification

Key process for the development of most bones, starting from a model of hyaline cartilage.

Description

Explore the various types of bones and their functions within the skeletal system. This quiz covers long, short, flat, irregular, and sesamoid bones, highlighting their structures and roles. Additionally, understand how the skeletal system supports the body, facilitates movement, and stores important minerals.