1 / 18

Motor mechanisms II

Motor mechanisms II. Review questions. Binding of ATP to myosin head causes:. a) actin filament to slide b) Myosin head to detatch from actin filament C) Myosin head to cock. What will happen when ADP and P i dissociate from myosin head?. A) head will detatch from actin filament

umeko
Download Presentation

Motor mechanisms II

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Motor mechanisms II

  2. Review questions

  3. Binding of ATP to myosin head causes: • a) actin filament to slide • b) Myosin head to detatch from actin filament • C) Myosin head to cock

  4. What will happen when ADP and Pi dissociate from myosin head? • A) head will detatch from actin filament • B) head will retract and pull actin filament • C) head will bind ADP again

  5. Ca++ induces muscle contraction by: • A) Causing actin monomers to assemble into a filament • B) making ATP available to bind to myosin head • C) allowing myosin head to bind to actin filament

  6. Muscle fiber types are the result of different types (isoforms) of myosin • Type I - slow fibers (aerobic) • Type II - fast fibers (anaerobic) • Type IIx - very fast • Type IIa - intermediate between II x and I • Types present in other vertebrates, not humans e.g., IIb in rats and other small mammals

  7. Changes between fiber types • In response to weigh training and anaerobic exercise • IIx ---> IIa • I --> Iia • Can IIa --> I? • Can increase cross sectional area of fast fiber types by weigh training

  8. Weight Training and Different Myosin Types                sedentary people have higher amounts of IIx               active people have more IIa fibers                    heavy weight-load repetitions.....                        decreases Fast IIx fibers and converts them to Fast IIa fibers                             nuclei stop expressing IIx gene and express IIa genes                             after 1 month all IIx  -->  IIa    (muscle also become more massive)   Can we recruit   slow  --->   fast ?   maybe...                        but no good evidence to date for slow to fast recruitments.

  9. Characteristics of other muscle types: • Cardiac muscle - found only in the heart, striated, gap junctions allow direct electrical signaling between cells • Smooth muscle - involuntary muscle, meshwork of actin and myosin, can contract more (greater shortening), but with less tension.

  10. 1 Muscle cell types schematic:1) skeletal2) cardiac3) smooth 2 3

  11. Skeletal muscle

  12. Cardiacmuscle http://www.youtube.com/watch?v=Cdl8Awn_lDY&feature=related http://www.youtube.com/watch?v=b1WD564sjWw&feature=related

  13. Smooth muscle

More Related