Lesson 3 of 12 · 6 min
Types of muscle
NCERT §17.2
In the last 200 m, Meher's leg muscles obey her; her heart speeds up on its own; her stomach, still holding breakfast, churns without asking. Three different muscles, three different bosses.
The lesson in notes
In short
Muscle is a specialised tissue of mesodermal origin and makes up about 40–50 per cent of an adult human's body weight.
Muscles show excitability, contractility, extensibility and elasticity.
By location there are three types: skeletal, visceral and cardiac.
Skeletal muscles are attached to the skeleton, look striped under a microscope (striated) and are under voluntary control; they bring about locomotion and changes of posture.
Visceral muscles line the inner walls of hollow organs such as the alimentary canal and reproductive tract. They are unstriped (smooth) and involuntary, and they move food along the gut and gametes along the genital tract.
Cardiac muscle is the muscle of the heart. Its cells join in a branching pattern; it is striated but involuntary, since the nervous system does not directly control it.