Muscle

Muscle
Three distinct types of muscle (L to R): smooth (non-striated), cardiac, and skeletal muscle
Identifiers
MeSHD009132
TA21975, 1994
FMA5022 30316, 5022
Anatomical terminology

Muscle is a soft tissue, one of the four basic types of animal tissue. Muscle tissue gives skeletal muscles the ability to contract. Muscle is formed during embryonic development, in a process known as myogenesis. Muscle tissue contains special contractile proteins called actin and myosin which interact to cause movement. Among many other muscle proteins, present are two regulatory proteins, troponin and tropomyosin.[1]

Muscle tissue varies with function and location in the body.

In vertebrates, the three types are:

  1. skeletal,
  2. cardiac (both striated), and
  3. smooth muscle (non-striated).[2]

Skeletal muscle tissue consists of elongated, multinucleate muscle cells called muscle fibers, and is responsible for movements of the body. Other tissues in skeletal muscle include tendons and perimysium.[3] Smooth and cardiac muscle contract involuntarily, without conscious intervention. These muscle types may be activated both through the interaction of the central nervous system as well as by receiving innervation from peripheral plexus or endocrine (hormonal) activation. Striated or skeletal muscle only contracts voluntarily, upon the influence of the central nervous system. Reflexes are a form of non-conscious activation of skeletal muscles, but nonetheless arise through activation of the central nervous system, albeit not engaging cortical structures until after the contraction has occurred.[citation needed]

The different muscle types vary in their response to neurotransmitters and hormones such as acetylcholine, noradrenaline, adrenaline, and nitric oxide depending on muscle type and the exact location of the muscle.[citation needed]

Sub-categorization of muscle tissue is also possible, depending on among other things the content of myoglobin, mitochondria, and myosin ATPase etc.[citation needed]

  1. ^ Ebashi, S.; Endo, M. (1968). "Calcium ion and muscle contraction". Progress in Biophysics and Molecular Biology. 18: 123–183. doi:10.1016/0079-6107(68)90023-0. ISSN 0079-6107. PMID 4894870.
  2. ^ Robson, Lesley G. (2017). "Vertebrate Embryo: Myogenesis and Muscle Development". eLS. Wiley. pp. 1–10. doi:10.1002/9780470015902.a0026598. ISBN 9780470015902.
  3. ^ Dave, Heeransh D.; Shook, Micah; Varacallo, Matthew (2024), "Anatomy, Skeletal Muscle", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 30725921, retrieved 2024-04-22