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Module 3: Skeletal system and articulations

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  • The 7 main jobs of the skeletal system.

    • Support,

    • mineral storage (calcium/phosphate).

    • lipid storage.

    • blood cell production.

    • protection of organs.

    • everage for movement.

    • ion balance.

  • Main differences between a baby's skull and an adult's.

    Foetal skulls have fontanelles (soft spots), two separate frontal bones, no mastoid process, and a larger cranium relative to the face.

  • The purpose of fibrous connective tissue in a baby's skull.

    Allows the skull to "mould" during delivery for a safer birth and provides space for rapid brain growth after birth.

  • Implications of a solid, fused skull at birth.

    Traumatic delivery for mother and child, potential damage to the birth canal, and restricted brain development.

  • Purpose of the vertebral foramen and intervertebral foramina.

    • Vertebral foramen: The path for the spinal cord.

    • Intervertebral foramina: Gaps between vertebrae for spinal nerves to exit.

  • Development of Cervical and Lumbar curves.

    • Cervical develops when the baby lifts its head.

    • Lumbar develops when the child begins to stand/walk. Both help maintain upright balance.

  • The unique feature of thoracic vertebrae.

    They are the only vertebrae with costal facets because they are the only ones that articulate with the ribs.

  • Difference between vertebrosternal (True) and vertebrochondral (False) ribs.

    • True ribs (1–7) connect direct connection to the sternum

    • False ribs (8–12) connect indirectly or are "floating."

  • Advantage of rib types for breathing.

    • True ribs provide a stable cage for protection

    • False ribs (8–10) are more mobile, allowing the chest volume to expand and contract.

  • Identification of Upper Limb bones.

    Includes the Humerus, Radius, Ulna, Carpals, Metacarpals, and Phalanges.

  • The structural divisions of a long bone.

    • Epiphysis (ends/spongy bone)

    • Diaphysis (shaft/compact bone)

    • Metaphysis (growth zone)

    • Medullary cavity (yellow marrow storage).

  • The general purpose of surface markings.

    They provide attachment sites for muscles, tendons, and ligaments and allow bones to form joint articulations.

  • Definition of Osteoid and how it becomes bone.

    • Osteoid is the organic matrix before calcium salts are added.

    • Osteoblasts trigger the deposition of calcium salts, which converts the soft osteoid into hard bone.

  • The role of Osteoblasts.

    • They produce new bone matrix through osteogenesis (or ossification).

    • They release proteins and organic components to create the initial matrix.

  • The role of Osteoclasts.

    They break down and remove bone matrix by releasing acids/enzymes, which releases stored minerals. (known as "Destroyers")

  • facts about Osteogenic (Osteoprogenitor) cells.

    • Mesenchymal stem cells that are the only bone cells to divide.

    • They produce daughter cells that eventually turn into osteoblasts.

    • They are essential for repairing fractures.

  • Where Osteogenic cells are located in the bone.

    • Inner cellular layer of the periosteum

    • endosteum (the layer lining the medullary cavity and blood vessel passageways).

  • General facts about Osteocytes.

    • These are mature bone cells that make up most of the cell population.

    • They develop from osteoblasts that have been completely surrounded by bone matrix.

    • They cannot divide.

  • Where Osteocytes live within the bone matrix.

    Each osteocyte occupies a lacuna (a small pocket) sandwiched between layers of the matrix.

  • How the body balances calcium levels.

    • PTH raises blood calcium by activating osteoclasts

    • Calcitonin lowers it

    • Vitamin D (calcitriol) helps with dietary absorption.

  • The 4 steps of bone repair.

    1. Hematoma (blood clot).

    2. Callus (internal/external bridge).

    3. Spongy bone replacement.

    4. Compact bone remodeling.

  • Function of the fibrocartilage pads in the knee.

    They act as shock absorbers, provide lateral stability, and help the bones fit together.

  • Why the knee has a complicated arrangement of ligaments.

    The bones don't fit perfectly and are always rolling across each other, so 7 major ligaments are needed for stability.

  • Mechanics of turning the palm upward.

    Achieved at the pivot joint where the Radius rotates around the Ulna, powered by the Biceps brachii.

  • Why the Hip is less likely to dislocate.

    The Acetabulum is a deep bony socket that provides a complete "cup" for the femur, unlike the shallow shoulder socket.

  • How the skeleton stays healthy over time.

    A constant cycle where Osteoclasts remove old matrix and Osteoblasts replace it with new bone.

  • Identification of Lower Limb bones often confused with upper limbs.

    Includes the Femur, Tibia, Fibula, Tarsals (ankle), Metatarsals (foot arch), and Phalanges (toes).

  • Easy way to distinguish Metacarpals vs. Metatarsals.

    Metacarpals are in the Carpus (hand/wrist area). Metatarsals are in the Tarsus (ankle/foot area).