B. Muscular Tissue:

Muscular tissue is mesodermal in origin consisting of different muscle fibres.
Muscle fibers have the capacity for contraction and stretching.
Outer covering muscle fiber is called sarcolemma.
The cytoplasm of muscle fiber is called sarcoplasm.
Single muscle fiber consists of fine longitudinal fibers called myofibrils.

 There are 3 types of muscular tissue.

1. Striated/Striped/Voluntary Muscles:
These muscles are long & cylindrical fibers with blunt ends.
Each fibre is bounded by an elastic sarcolemma & contains many acentric nuclei.
They are found in the body wall, limbs, pharynx, beginning of the esophagus etc.
These are under conscious or will control.
Dark and light bands are present.
They are also called striped or skeletal muscles.

2. Unstriated/Unstriped/Involuntary Muscles:

These muscles are spindle shaped tapering at both ends with numerous fine longitudinal myofibrils.
Each fibers are bounded by its plasma membrane.
These are found in hollow visceral organs such as the alimentary canal, blood vessels, and genital tracts.
They are under the control of the automatic nervous system.
Each myofibril contains a single oval nucleus in the middle.
Dark light bands are absent.
They are also called visceral muscles.

3. Cardiac Muscles

• These muscles are located only in the heart.
• Structurally these muscles form intermediate-type walls having the properties of both striped and unstriped muscles.
• The cardiac muscles are myogenic. It means that the contractions are generated within the muscles. 
• These contract rhythmically but do not get fatigued.
• These are supplied by both the central nervous system and the automatic nervous system. 
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