Question 2Which of these are shortened during a muscle twitch?O ActinO I bandமவவுO Z-discMyosinO Azone

Answered: Which of these are shortened during a…

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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The muscle fiber is made of thin filaments which are actin and thick filaments which are myosin. I band is the length of the Z line to the left and right. Between the I bands is the A band which consists of actin and myosin and the M line.

For a muscle twitch to happen, the actin slides along the myosin shortening the sarcomere. The thick and thin filaments do not shorten. The sarcomere is the part of the muscle fiber between two Z-lines. This means when the sarcomere contracts, the z-lines come closer together. The H-zone is in-between A-zones. The H-zone and also the I-band shorten during muscle twitch.