MSK Upper Extremity

11 flashcards · Other · by Jared Blackwell

1. What is Erb's Palsy

   Affects the C5-C6 Superior Trunk. Can occur if baby's neck is stretched so the head and shoulders pass birth through the birth canal.

2. Describe thin and thick filaments and how the interact.

   Thin filaments have actin. Thick filaments have myosin. Myosin attaches to troponin on actin after Ca2+ releases tropmyosin. ATP releases myosin.

3. Describe structure of sarcomeres

   Dark A bands Light I bands Z line between I band Z line to Z line is sarcomere.

4. What determines the amount of muscle force generated?

   The total number of actin-myosin cross bridges form for contraction.

5. Describe how I bands and A bands contract

   I bands narrow. A bands don't change. Zone of overlap increases during contraction. H zone shortens.

6. How do action potentials cause contraction of sarcomeres?

   Myofibrils are surrounded by SR. SR stores calcium. T-tubules invaginate sarcolemma. AP spreads into T-tubules Triad has SRs with t-tubule inbetween. Depolarization in T-tubule causes SR to release Ca2+ on sarcomere for contraction.

7. Describe Type 1 and Type 2 muscle fibers

   Type 1 is slow, red, oxidative, walking and stamina. Type 2 is fast, white, glycolytic, weights, sprints.

8. What do satellite cells do?

   Pluripotent stem cells activate with injury or exercise to repair muscle.

9. Where does brachial plexus come out of?

   Comes out of scalenes.

10. What causes thoracic outlet syndrome?

    Tightness of scalene muscles. Extra long cervical transverse process or cervical ribs also.

11. Describe Klumpke Paralysis

    C8-T1 Inferior Trunk Injury