Human Anatomy: The Skeletal System

What are the five primary functions of the skeletal system?

The primary functions are support, protection of internal organs, movement (leverage for muscles), mineral storage (calcium and phosphate), and hematopoiesis (blood cell production in red bone marrow).

What are the two main divisions of the adult human skeleton?

The two main divisions are the axial skeleton, which forms the central axis of the body, and the appendicular skeleton, which consists of the limbs and their girdles.

Name the three main components of the axial skeleton.

The axial skeleton consists of the skull, the vertebral column, and the thoracic cage (ribs and sternum).

What does the appendicular skeleton primarily consist of?

The appendicular skeleton primarily consists of the bones of the upper and lower limbs, along with the pectoral (shoulder) and pelvic (hip) girdles.

What are the four main classifications of bones based on their shape?

Bones are classified as long bones (e.g., femur), short bones (e.g., carpals), flat bones (e.g., sternum), and irregular bones (e.g., vertebrae).

Name the four main types of bone cells and their primary functions.

Osteogenic cells are stem cells. Osteoblasts are bone-forming cells. Osteocytes are mature bone cells that maintain the bone matrix. Osteoclasts are large cells that resorb (break down) bone matrix.

What is the primary structural difference between compact bone and spongy bone?

Compact bone is dense and solid, forming the outer layer of most bones, providing strength. Spongy bone has an open, porous structure with trabeculae, found in the interior of bones, reducing weight and housing bone marrow.

What is the periosteum and what is its primary function?

The periosteum is a tough, fibrous membrane that covers the outer surface of bone, except at articular surfaces. It provides attachment points for tendons and ligaments, contains blood vessels and nerves, and houses osteoblasts for bone growth and repair.

What are the two types of bone marrow and where are they typically found?

Red bone marrow, found primarily in spongy bone (especially in flat bones and epiphyses of long bones), produces blood cells. Yellow bone marrow, found in the medullary cavity of long bones, stores fat.

What are the two types of ossification (bone formation)?

The two types are endochondral ossification, where bone tissue replaces a hyaline cartilage model, and intramembranous ossification, where bone develops directly from mesenchymal connective tissue membranes.

Name the three main structural classifications of joints.

The three main structural classifications are fibrous joints (bones joined by fibrous connective tissue), cartilaginous joints (bones joined by cartilage), and synovial joints (bones separated by a fluid-filled joint cavity).

What is the distinguishing feature of a synovial joint?

The distinguishing feature of a synovial joint is the presence of a fluid-filled synovial cavity between the articulating bones, which allows for smooth movement and reduces friction.

What is the primary difference in function between ligaments and tendons?

Ligaments connect bone to bone, providing stability to joints. Tendons connect muscle to bone, facilitating movement by transmitting muscle contraction forces.

What are the five regions of the vertebral column, from superior to inferior?

The five regions are cervical (7 vertebrae), thoracic (12 vertebrae), lumbar (5 vertebrae), sacrum (5 fused vertebrae), and coccyx (3-5 fused vertebrae).

Briefly list the four major steps in the repair of a bone fracture.

The four major steps are hematoma formation, fibrocartilaginous callus formation, bony callus formation, and bone remodeling.