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Anatomy & Physiology: The Skeletal System

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Terms in this set (28)

  • Main parts of the skeletal system

    Bones, joints, cartilages, and ligaments.

  • Two subdivisions of the skeleton

    Axial skeleton and appendicular skeleton.

  • Functions of bones

    Support the body, protect soft organs, allow movement, store minerals and fats, and blood cell formation (hematopoiesis).

  • Two types of osseous tissue

    Compact bone (dense and smooth) and spongy bone (needlelike pieces with many open spaces).

  • Four bone shape classifications

    Long, flat, short, and irregular bones.

  • Characteristics of long bones

    Longer than wide, shaft with enlarged ends, mostly compact bone with spongy bone at ends. Examples: femur, humerus.

  • Characteristics of flat bones

    Thin, flattened, usually curved, two layers of compact bone with spongy bone in between. Examples: skull bones, ribs, sternum.

  • Characteristics of short bones

    Cube-shaped, mostly spongy bone with outer compact bone. Sesamoid bones form within tendons. Examples: carpals, tarsals, patella.

  • Characteristics of irregular bones

    Irregular shape, do not fit other categories. Examples: vertebrae, hip bones.

  • Diaphysis of a long bone

    Shaft that makes up most of the bone's length, composed of compact bone.

  • Periosteum

    Fibrous connective tissue membrane covering the diaphysis, secured by perforating (Sharpey’s) fibers.

  • Epiphysis

    Ends of long bones, mostly spongy bone enclosed by thin compact bone layer, covered by articular cartilage.

  • Epiphyseal plate and line

    Plate is hyaline cartilage causing lengthwise growth in young bones; line is its remnant in adults.

  • Medullary cavity contents

    Contains yellow marrow (fat) in adults and red marrow (blood cell formation) in children.

  • Osteon (Haversian system)

    Structural and functional unit of compact bone, consisting of central canal and concentric lamellae.

  • Function of canaliculi

    Tiny canals connecting osteocytes to the central canal, forming a nutrient transport system.

  • Bone matrix composition

    Organic collagen fibers provide flexibility and tensile strength; calcium salts provide hardness and resistance to compression.

  • Ossification

    Process of bone formation occurring on hyaline cartilage models or fibrous membranes.

  • Appositional bone growth

    Growth in bone width by osteoblasts adding matrix outside and osteoclasts removing bone inside the diaphysis.

  • Role of parathyroid hormone (PTH) in calcium regulation

    Released when blood calcium is low; activates osteoclasts to break down bone and release calcium into blood.

  • Types of bone fractures

    Closed (simple): bone breaks but skin intact; open (compound): bone breaks and penetrates skin.

  • Four major events in bone fracture repair

    Hematoma formation, fibrocartilage callus formation, bony callus formation, and bone remodeling.

  • Axial skeleton components

    Skull, vertebral column, and bony thorax.

  • Number of vertebrae in vertebral column

    26 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, plus sacrum and coccyx formed by fused vertebrae.

  • Primary vs secondary spinal curvatures

    Primary curvatures (thoracic, sacral) present at birth; secondary curvatures (cervical, lumbar) develop after birth.

  • Types of synovial joints by shape

    Plane, hinge, pivot, condylar, saddle, and ball-and-socket joints.

  • Functions of synovial joint features

    Articular cartilage reduces friction, articular capsule encloses joint, joint cavity contains synovial fluid, reinforcing ligaments stabilize joint.

  • Developmental significance of fontanels

    Fibrous membranes in fetal skull allowing compression during birth and brain growth; ossify by about 2 years old.