BIOL 2160 Chapter : Chapter 12 Muscles
Document Summary
It is critical that you view the video before coming to class! 12. 31monitor tension : series-elastic component, non-contractile tendons and connective tissue absorb tension as the muscle starts to contract, tendons first must be pulled tight, before the muscle contraction results in shortening. Intra vs extrafusal fibers: extrafusal are , contractile cells of the muscle; have myofibrils, responsible for skeletal muscle coordination, innervated by alpha motor neurons. Wider in center and functions as length detector. Muscles with fine control have lots of spindles. Muscle fibers extend length of muscle from tendon to tendon. Structure of a skeletal muscle fiber fig 12. 2. Orderly arrangement of thick and thin filaments: actin-thin, myosin-thick. Striations due to thick and thin filaments which run parallel to long axis. A band - dark striations, thick filaments (does not change) I band - light striations, thin filaments only, no overlap (disappears in contraction) Each g actin has a binding site for myosin.
