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Physiology Review (ppt modified from recreation.ucsb/ess/ess40/chap8.htm)

Physiology Review (ppt modified from http://www.recreation.ucsb.edu/ess/ess40/chap8.htm). The SARCOMERE is the functional unit of the muscle. A sarcomere is found between two Z lines. The Muscle Fiber Is Composed of Special Contractile Proteins.

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Physiology Review (ppt modified from recreation.ucsb/ess/ess40/chap8.htm)

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  1. Physiology Review(ppt modified from http://www.recreation.ucsb.edu/ess/ess40/chap8.htm) The SARCOMERE is the functional unit of the muscle. A sarcomere is found between two Z lines.

  2. The Muscle Fiber Is Composed of Special Contractile Proteins • Myosin is the main, thick structural protein in the sarcomere. It has cross bridges for attaching to the Actin protein. • Actin is the main, thin structural protein in the sarcomere. Each actin molecule has a binding site that can attach with a Myosin cross bridge. • Actin and myosin are contractile proteins.

  3. Tropomyosin and Troponin Are Regulatory Proteins. These regulatory proteins control the muscle contraction process. • They either allow or block actin-myosin interaction depending on their configuration.

  4. TROPOMYOSIN • Tropomyosin covers the actin binding sites. • This prevents the union of actin with myosin cross bridges.

  5. TROPONIN • Troponin has three binding sites: • one binds to Tropomyosin, one to Actin, and one to Ca+ ions. • When calcium combines with troponin, tropomyosin slips away from its blocking position between actin and myosin. • With this change actin and myosin can interact and muscle contraction can occur.

  6. fig.cox.miami.edu/.../150/neuro/tropomyosin.jpg

  7. Sliding Filament Mechanism • The myosin cross bridges can bind to the actin. • After binding the thin (actin) filaments are pulled toward the center of the sarcomere. • This is known as the Sliding Filament Mechanism.

  8. http://people.eku.edu/ritchisong/crossbridge3.gif

  9. SLIDING FILAMENT MECHANISM • Neither the thick nor thin filaments change in length. They change their position with one another. • The actin slides closer together between the thick filaments.

  10. http://3dotstudio.com/contract.gif

  11. The myosin cross bridges pull the thin actin filaments inward. • A single power stroke pulls the actin inward only a small percentage of the total distance. • Complete shortening occurs by repeated cycles of the power stroke. • The link between myosin and actin is broken at the end of one cross bridge cycle. A cross bridge returns to its original position and can connect to the next actin molecule position, pulling the actin filament further.

  12. www.octc.kctcs.edu

  13. Muscle contraction • The process starts when the muscle cell is depolarized • A neuron sends action potentials to muscle fibers. • This neuron releases acetylcholine at the neuromuscular junction. • This produces an action potential over the entire muscle cell membrane. • Sodium/Potassium pumps are not working when Ach is on the receptors of muscle cells…chaos ensues!

  14. The Release of Calcium Ions from the sacroplasmic reticulum starts the Sliding Process. • Calcium from the SR binds with troponin. • By this event, tropomyosin is pulled off the binding sites of actin • This allows the myosin cross bridges to bind to actin and slide this protein.

  15. Test Information… • 60 points total • 20 Anatomy ID—real people, pictures and microscope slides • Some anatomy on Physiology portion • Body movements • Draw a line drawing of sarcomere

  16. Name this muscle

  17. Muscle?

  18. Muscle?

  19. Notecardable items… • Fill in the blank (with words provided) of body movements (4) • Two short answers have choices…choose the question you can answer the MOST completely. • Steroid question vs. muscle connections • Mitochondria’s role in contraction vs blood supply

  20. Short Answer Questions(notecardable…) • Explain the protein alignment within a sarcomere. Draw a diagram as well…

  21. Short Answer Questions(notecardable…) • Physiology of muscle cell—broken into 5 questions • Three phases of function of MC • Function of neuromuscular junction • Stimulation in detail (# in order) • Contraction in detail (# in order) • Relaxation in detail (# in order)

  22. Short Answer Questions(notecardable…) • Antagonistic/Synergistic as it relates to function of muscles • Difference between strains, sprains and contusions • Three factors contributing to muscle aging • Case study

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