Skeletal Elements and Functions Quiz

Skeletal Elements and Function

• Protect organ systems such as the skull, vertebral canal and chest cage

Bony Skeleton

• Consists of approximately 200 bones connected by cartilage, fibrous and synovial joints.
• Bones have a connective tissue sheath called periosteum, which acts like a stocking.
• Bone shape is determined by genetics and structural demand.
• Bones are categorized into: long, short, flat, and irregular bones.
• Long bones: found in limbs, with diaphysis and epiphysis at the ends.
• Short bones: found in the wrist and ankle.
• Flat Bones: Include ribs, breast bone, shoulder blade and bones of the skull.
• Irregular bones: vertebrae and bones at the base of the skull.
• Some skull bones contain air-filled cavities.
• Sesamoid bones are located within tendons for example, the kneecap.

Joints

• These are connections between bones or cartilage, allowing for movement and force transmission.
• Categorized as immovable (synarthroses) or movable (diarthroses).

Immovable Joints (Synarthroses)

• Skeleton parts are separated by tissues like cartilage or connective tissue.
• Include interarticular disks, articular lips and intraarticular ligaments.
• Menisci, made of fibrocartilage, are found in the knee.

Movable Joints

• Have a joint space with synovial fluid.
• Joint cartilage is mostly hyaline cartilage, providing shock absorption and mechanical support.
• Joint cartilage lacks blood vessels, requiring nutrients from synovial fluid.
• Optimal cartilage nutrition requires regular movement, loading, and unloading.
• Lack of movement can lead to osteoarthritis, particularly in older people.
• Joint capsule is a continuation of the periosteum with an outer fibrous layer and an inner synovial membrane.
• Synovial fluid lubricates and nourishes the joint cartilage.

Slightly Movable Joints (Amphiarthroses)

• Have limited mobility due to the shape of their facets and strong ligaments.
• Examples include the tibiofibular joint and the sacroiliac joint.

Types of Joints

• Joints can be classified based on their mobility axes, degrees of freedom, or components.
• Classification by shape and configuration of joint surfaces:
• Ball-and-socket joints: allow movement in three axes (hip and shoulder joints).
• Condyloid joints: allow movement in two axes (wrist and occipital condyles).
• Hinge joints: allow movement in one axis (elbow joint).
• Pivot joints: allow rotation around one axis (radioulnar joint).
• Saddle joints: allow movement in two axes (wrist joint).
• Plane joints: allow gliding movements (small joints of vertebrae).

Joint Mechanics

• The arrangement of muscles and ligaments determines the direction of movement.
• Muscles provide forces to ensure joint integrity and movement.
• Limitations to movement are caused by bone, muscle, ligaments, and soft tissue.
• Movements occur around axes, often related to specific joint actions.

Muscles

• Muscles are responsible for movement, and consist of bundles of muscle fibers wrapped in connective tissue.
• They are anchored to bones by tendons, which transmit forces for movement.
• Most muscles have an origin and an insertion point.
• Muscles may be two, three, or four-headed with multiple origins.
• Digastric muscles have a single head but one intersecting tendon.
• Muscles can be classified according to:
• The way they are inserted into tendons.
• Whether they act on one or multiple joints (diarthric or polyarthric).
• How they work together or oppose each other (synergists or antagonists).

Test your knowledge on the skeletal system, including the structure and function of bones and joints. This quiz covers the types of bones, their classifications, and the protective roles they play in the body. Delve into the details of the skeletal framework and enhance your understanding of human anatomy.