Skeletal muscles have levels of organization from the macroscopic to the microscopic. 226Muscles permit movement and have other functions as well. 226
12.2 Mechanism of Muscle Fiber Contraction
Following nervous stimulation, a chain of events leads to muscle fiber contraction. 231Nervous stimulation requires a neuromuscular junction where the stimulus is passed from nerve fiber to muscle fiber. 232When a muscle fiber contracts, the myofilament myosin breaks down ATP. 233
12.3 Whole Muscle Contraction
Laboratory observations have established the basics of whole muscle contraction. 234In the body, muscles have tone and vary in the strength of contraction. 234
12.4 Energy for Muscle Contraction
Cellular respiration, creatine phosphate breakdown, and fermentation are three sources of ATP for muscle contraction. 236Muscle fibers differ in structure and the way they acquire ATP; therefore, certain type fibers help us perform one sport compared to another. 238
12.5 Homeostasis
The muscular system works with the other systems of the body to maintain homeostasis. 240 s