System Function: Musculoskeletal - Massage and Bodywork Licensing Examination Mblex

1. What is the primary role of bursae in the musculoskeletal system?

   Reduce friction by cushioning between tissues near joints. These fluid-filled sacs act as shock absorbers, minimizing wear on tendons and bones during repetitive movements.

2. What is the term for movement that increases the angle of a joint?

   Extension. This action straightens the joint, increasing the distance between bones in the sagittal plane for movements like straightening the arm.

3. What is the term for lifting the foot upward toward the shin at the ankle joint?

   Dorsiflexion. This ankle movement flexes the foot upward, reducing the angle with the tibia, aiding in walking by clearing the toes.

4. What is the primary role of synovial fluid in a synovial joint?

   Lubricates and nourishes articular cartilage to reduce friction. Secreted by the synovial membrane, it provides viscosity for smooth joint motion and delivers nutrients to avascular cartilage.

5. What is the term for pointing the toes downward at the ankle joint?

   Plantar flexion. This ankle movement extends the foot downward, as in pressing a gas pedal, involving gastrocnemius contraction.

6. What ion binds troponin to initiate skeletal muscle contraction?

   Calcium ($Ca^{2+}$). Its release from the sarcoplasmic reticulum triggers a conformational change in troponin, exposing actin binding sites for contraction.

7. What type of joint is characterized by a joint cavity and synovial membrane?

   Synovial (diarthrodial) joint. These freely movable joints feature a fluid-filled cavity enclosed by a membrane, allowing extensive range of motion.

8. What is the term for moving a limb away from the body midline?

   Abduction. Performed in the frontal plane, it moves appendages laterally from the median plane, such as raising the arm sideways.

9. What is the name of the fibrous connective tissue that attaches muscle to bone?

   Tendon. Composed of dense collagen, it transmits muscular force to the skeleton, enabling joint movement.

10. What is the term for moving a limb toward the body midline?

    Adduction. Occurring in the frontal plane, it returns appendages medially toward the median plane, like lowering the arm to the side.

11. What protein forms the thin filaments in skeletal muscle?

    Actin. These filaments slide past myosin during contraction, facilitated by regulatory proteins like troponin and tropomyosin.

12. What is the term for movement that decreases the angle of a joint?

    Flexion. This action bends the joint, bringing bones closer together in the sagittal plane for movements like bending the knee.

13. Which joint type primarily permits flexion and extension in one plane (for example, elbow)?

    Hinge joint. Its convex-concave structure restricts motion to a single plane, optimizing for unidirectional bending and straightening.

14. What is the term for rotating the forearm so the palm faces posteriorly or downward?

    Pronation. This rotation crosses the radius over the ulna, orienting the hand for actions like turning a doorknob.

15. What connective tissue sheath surrounds the entire skeletal muscle?

    Epimysium. This outermost layer encases the whole muscle, merging with tendons to anchor it to bone.

16. What is the functional unit of a skeletal muscle fiber that produces contraction?

    Sarcomere. It consists of overlapping actin and myosin filaments that shorten via sliding during muscle contraction.

17. Which joint type permits movement in multiple planes including circumduction (for example, shoulder)?

    Ball-and-socket joint. The spherical head fitting into a cup-like socket enables rotation in three axes, supporting versatile movements like rotation and swinging.

18. What connective tissue sheath surrounds an individual muscle fiber?

    Endomysium. This layer of connective tissue encapsulates single fibers, providing structural support and facilitating nutrient exchange.

19. What connective tissue sheath surrounds a fascicle (bundle of muscle fibers)?

    Perimysium. It bundles groups of muscle fibers into fascicles, aiding in force transmission and vascular supply.

20. What is the term for rotating the forearm so the palm faces anteriorly or upward?

    Supination. This rotation aligns the radius and ulna parallel, positioning the hand for actions like holding a bowl.

21. What protein forms the thick filaments in skeletal muscle?

    Myosin. These filaments contain cross-bridges that interact with actin to generate force during muscle contraction.

22. What is the name of the connective tissue band that connects bone to bone across a joint?

    Ligament. Made of fibrous collagen, it stabilizes joints by limiting excessive motion between articulating bones.

23. What is the primary function of the musculoskeletal system in human movement?

    Provides support, protection, and movement via muscles acting on bones. The musculoskeletal system integrates skeletal structures with muscular contractions to facilitate bodily support, organ protection, and dynamic locomotion.

24. What type of muscle tissue is primarily responsible for voluntary skeletal movement?

    Skeletal (striated, voluntary) muscle. This muscle type features striations for forceful contractions and is under conscious control, enabling precise movements of the skeleton.

25. What is the immediate energy source used by myosin heads during cross-bridge cycling?

    ATP. Hydrolysis of this molecule powers the myosin head's power stroke, enabling cross-bridge formation and filament sliding.

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