BIOL 031 Lecture Notes - Lecture 23: Neuromuscular Junction, Sarcomere, Motor Neuron
18 Aug 2020
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Muscle tension: the force created by contracting muscle. Load: a weight or force that opposes contraction of a muscle. Contraction: the creation of tension in a muscle; an active process that requires energy input from atp. Relaxation: the release of tension created by a contraction. In intact muscles, one contraction-relaxation cycle is calleda muscle twitch. Actin and myosin slide past each other during contraction. The length of the a band of a myo bril remains constant during contraction. Sliding lament theory of contraction: overlapping actin and myosin. Laments of xed length slide past one another in an energy-requiring process, resulting in muscle contraction; the sliding of thin actin. Laments along the thick myosin laments as the actin laments move toward the m line in the center of the sarcomere. A relaxed sarcomere has a large i band and an a band whose length is the length of the thick lament.
