Muscle pt 2

Muscle Groups

• There are three main types of muscle tissue: striated or skeletal, non-striated or smooth or visceral, and cardiac.

Striated/Skeletal Muscle

• Responsible for moving limbs and maintaining posture.
• Attached to bones by tendons and contains blood vessels and nerves.
• Each muscle fibre has a long cylindrical shape, measuring between 0.02 and 0.08 mm in diameter.
• The arrangement of muscle fibres depends on the function of the muscle.

Non Striated/Smooth/Visceral Muscle

• Found in soft tissue structures, like the walls of blood and lymphatic vessels, the alimentary canal.
• Responsible for contracting and relaxing to move fluids and solids within these structures.
• Can sustain contraction for long periods of time.
• Cells are long, narrow, and spindle-shaped.
• Under the autonomic nervous system.

Cardiac Muscle

• Found only in the wall of the heart.
• Exhibits rhythmic contractions to pump blood.
• Under the autonomic nervous system and has an intrinsic pacemaker system.
• Possesses intercalated discs, which allow for coordinated contraction.
• Each fibre is roughly rectangular in shape.

Comparison of Muscle Types

• Striated muscle: Voluntary control, long cylindrical fibres, contraction for short periods.
• Smooth muscle: Involuntary control, spindle-shaped fibres, sustained contraction for long periods.
• Cardiac muscle: Involuntary control, rectangular fibres, rhythmic contraction.

Comparisons Microscopically

• Striated muscle: Fibres are striated, containing multiple nuclei.
• Smooth muscle: Fibres are smooth, with one centrally placed nucleus.
• Cardiac muscle: Fibres are striated, with one or two centrally placed nuclei and intercalated discs.