PHGY 209 Lecture Notes - Lecture 3: Myoglobin, Myofibril, Skeletal Muscle
12 Jan 2018
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Document Summary
Excitation-contraction coupling: what the ca+ does when it"s released from the sr in to the muscle fiber cytoplasm: Troponin and tropomyosin are found along the actin filament (thin filaments) Troponin: small globular protein that are part of a larger protein family group, bind ca+ ions and are activated by them found all on the length of the thin filament. Actin long thin protein that wraps around and around the thin filaments. Resting muscle: ca+ concentration in the muscle fiber is very low so the troponin proteins aren"t activated. In those conditions, the myosin head groups can"t bind to the thin filaments because the troponin isn"t activated to allow a site for the myosin head to bind. How does ca+ works to induce a muscle contraction: process. When an action potential comes from a motor neuron and triggers depolarization in the muscle fiber that initiates an action potential in the muscle fiber.
