1. Musculo-skeletal system

2. Objectives Understand: Understand:  the histology of striated muscle  The structure and role of fast and slow twitch muscle fibres  Muscle contraction (role of actin, myosin, Ca ions and ATP).  The structure and role of neuromuscular junctions.  The structure of compact bone and a synovial joint.

3. Muscle structure

4. Muscle structure http://www.life.uiuc.edu/crofts/bioph354/lect16&17.html http://www.life.uiuc.edu/crofts/bioph354/lect16&17.html

5. Neuromuscular junction http://www.blackwellpublishing.com/matthews/myosin.html

6. Motor neurone end plate

7. Cross bridge structure. http://www.univie.ac.at/cga/courses/be522/emg/ scroll down to see units working together http://www.univie.ac.at/cga/courses/be522/emg/

8. Actin structure

9. Muscle contraction

10. Muscle movement AUDIO http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__breakdown_of_atp_and_cross- bridge_movement_during_muscle_contraction.html http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__breakdown_of_atp_and_cross- bridge_movement_during_muscle_contraction.html http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__breakdown_of_atp_and_cross- bridge_movement_during_muscle_contraction.html http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__breakdown_of_atp_and_cross- bridge_movement_during_muscle_contraction.html TROPININ MOVEMENT http://www.sci.sdsu.edu/movies/actin_myosin_gif.html http://www.sci.sdsu.edu/movies/actin_myosin_gif.html http://www.sci.sdsu.edu/movies/actin_myosin_gif.html

11. After a muscle contraction Calcium ions are actively reabsorbed into the sarcoplasmic recticulum. Calcium ions are actively reabsorbed into the sarcoplasmic recticulum. In a resting muscle there is only enough ATP for 8-10 muscle twitches (60 m race). In a resting muscle there is only enough ATP for 8-10 muscle twitches (60 m race). ATP stores need to be replenished. ATP stores need to be replenished.

12. Muscle contraction can also be stimulated by muscle spindles (2 - 12 modified fibres). Intrafusal fibres Intrafusal fibres Arranged in parallel to surrounding muscle fibres (exrafusal fibers). Arranged in parallel to surrounding muscle fibres (exrafusal fibers). Associated to sensory receptors (such as annulospiral endings. Associated to sensory receptors (such as annulospiral endings. Provide feedback on contraction, length, position and rate. Provide feedback on contraction, length, position and rate.

13. 2 types of muscle fibre Fast/twitch fibres Slow/tonic fibres - Myoglobin - - Colour – - Sarcoplasm - - Nucleus - - Fibrils - - Size - - Conduction velocity - - Speed of response – All or nothing - Type of response - summation - Use -