Types

Main article: Muscle tissue

https://upload.wikimedia.org/wikipedia/commons/thumb/e/e5/414_Skeletal_Smooth_Cardiac.jpg/220px-414
                                   _Skeletal_Smooth_Cardiac.jpg

Classification of muscles

The body contains three types of muscle tissue: (a) skeletal muscle, (b) smooth muscle, and (c)
cardiac muscle

Muscle tissue is a soft tissue, and is one of the four fundamental types of tissue present in
animals. There are three types of muscle tissue recognized in vertebrates:

·         Skeletal muscle or "voluntary muscle" is anchored by tendons (or by aponeuroses at a few
places) to bone and is used to effect skeletal movement such as locomotion and in maintaining
posture. Though this postural control is generally maintained as an unconscious reflex, the muscles
responsible react to conscious control like non-postural muscles. An average adult male is made up
of 42% of skeletal muscle and an average adult female is made up of 36% (as a percentage of body
mass).^[5]

·         Smooth muscle or "involuntary muscle" is found within the walls of organs and structures
such as the esophagus, stomach, intestines, bronchi, uterus, urethra, bladder, blood vessels, and
the arrector pili in the skin (in which it controls erection of body hair). Unlike skeletal muscle,
smooth muscle is not under conscious control.

·         Cardiac muscle (myocardium), is also an "involuntary muscle" but is more akin in
structure to skeletal muscle, and is found only in the heart.

Cardiac and skeletal muscles are "striated" in that they contain sarcomeres that are packed into
highly regular arrangements of bundles; the myofibrils of smooth muscle cells are not arranged in
sarcomeres and so are not striated. While the sarcomeres in skeletal muscles are arranged in
regular, parallel bundles, cardiac muscle sarcomeres connect at branching, irregular angles (called
intercalated discs). Striated muscle contracts and relaxes in short, intense bursts, whereas smooth
muscle sustains longer or even near-permanent contractions.

https://en.wikipedia.org/wiki/Muscle