Types of Muscle

This lesson covers: 

  1. The functions of different types of muscles
  2. Key differences between skeletal, cardiac, and smooth muscles
  3. The structure and arrangement of different muscle types

The functions of the different types of muscle

Muscles, through the contraction of muscle cells, facilitate body movement.


While many muscles contract under conscious control, some operate involuntarily without the need for conscious thought.

Illustration showing skeletal muscle, cardiac muscle, and smooth muscle.

These muscles are categorised into three types:

  1. Skeletal muscle - This muscle forms the majority of the body's muscles and is attached to bones to move parts of the body like the arms or legs.
  2. Cardiac muscle - This muscle is unique to the heart, and functions to circulate blood.
  3. Smooth muscle - This muscle is located in the walls of hollow organs like blood vessels and the intestines, and typically functions to move substances through these organs.

Key differences between skeletal, cardiac, and smooth muscles

Each of the three muscle types has distinct structural and functional characteristics.

FeatureSkeletal muscleCardiac muscleSmooth muscle
Fibre structureTubular, striatedBranched, striatedSpindle-shaped, non-striated
Nuclei per fibreMultipleSingleSingle
ArrangementRegular, parallel bundles of myofibrilsBranching network of myofibrilsUnorganised, no myofibrils
ControlVoluntaryInvoluntaryInvoluntary
Type of stimulation requiredNeurogenic - contracts when stimulated by motor neuron impulsesMyogenic - contracts automatically without nervous inputNeurogenic, and can also stretch in response to pressure
Contraction speedFastIntermediateSlow
Contraction durationShortIntermediateLong-lasting

Skeletal muscle fibres and cardiac muscle fibres show regular striations or stripes due to the arrangement of contractile proteins within myofibrils.


Smooth muscle fibres show no striations or stripes under the microscope.