BIOL 2410 Lecture Notes - Lecture 27: Skeletal Muscle, Internal Anal Sphincter, Phosphocreatine
9 Dec 2016
School
Department
Course
Professor
Document Summary
A single twitch does not produce maximum tension. If the muscle bre continues to receive action potentials before the previous contraction event has ended, summation occurs. Complete tetanus -> stimuli occur rapid enough that there is not intermittent relaxation. Cant relax diaphragm - ability to breathe is compromised. Incomplete tetanus -> stimuli do not occur as quickly and there is some relaxation in between. The force of muscle contraction depends on how many motor units are recruited. A single whole muscle is composed of multiple motor units. Muscle contraction will vary according to the types of motor units that are active and how many of each are active: weak stimulus activated motor units with the lowest threshold. Activates slow-twitch bres resistant to fatigue: a stronger stimulus will recruit motor neutrons with a higher threshold. More motor units are now activated -> force of contraction will increase.
