Muscular System - Notes, Biology | IBPS PO Prelims & Mains Preparation - Bank Exams PDF Download

Muscular System

• Human body has about 639 types of muscles.
• Muscles specialized to contraction are of 3 types :
  • Striated
  • Unstriated and
  • Cardiac.

Striated Muscles

• Striated Muscles are also called Skeletal Muscles. These muscles are mostly attached to bones by tendons and takes part in voluntary movements under conscious control of brain.
• Therefore they are called voluntary muscles. Each muscle fibre shows dark and light striations and is covered by a sheath, the sarcolemma.

Striated Muscles

• Its cytoplasm is called sarcoplasm in which are present large number of contractile myofibrils.
• Myofibrils are made up of thick myosin and thin actin filaments.
• They are present in limbs, tongue, pharynx, etc.

Unstriated Muscles

• These smooth muscles are involuntary muscles.
• Functionally they are of two types – single unit and multi unit.
• Single unit smooth muscles are present in urinary bladder and gastro intestinal tract.
• Multi unit smooth muscles are present in walls of large blood vessels.

Cardiac Muscles

• They are involuntary, striated and non fatigued fibers which are found in the wall of heart where they form myocardium.
• They generate their own wave of excitation.