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Overview of Muscle Types and Functions

Nov 7, 2024

Lecture on Muscle Types

Introduction to Muscles

  • Muscles are associated with movement.
  • Think broadly about different movements in the body.

Types of Muscles

  1. Skeletal Muscle

    • Example: Leg muscles moving while playing soccer.
    • Attachment: Typically attached to bones via tendons.
      • Not all skeletal muscles attach to bones via tendons.
      • Example: External oblique muscle attaches via aponeurosis, a flat tendon-like structure.
    • Identification: Visible muscles on the body.
  2. Cardiac Muscle

    • Found exclusively in the heart.
    • Specialized cells unique to the heart.
  3. Smooth Muscle

    • Found in hollow organs (e.g., stomach, intestines) and blood vessels (e.g., aorta).
    • Located in the walls of these structures to aid movement (e.g., food through stomach).

Control of Muscle Movement

  • Skeletal Muscle: Voluntary control (e.g., choosing to move).
  • Cardiac Muscle: Involuntary control (automatic, heart beats without conscious effort).
  • Smooth Muscle: Involuntary control (automatic, slow movements in organs and vessels).

Speed of Muscle Movement

  • Smooth Muscle: Slowest.
  • Cardiac Muscle: Intermediate speed.
  • Skeletal Muscle: Fastest, allowing quick, voluntary movements.

Structure and Appearance of Muscle Cells

  1. Smooth Muscle Cells

    • Shape: Eye or almond-shaped, also known as spindle-shaped.
    • Nuclei: One, centrally located.
  2. Cardiac Muscle Cells

    • Shape: Branched.
    • Nuclei: One or two, centrally located.
  3. Skeletal Muscle Cells

    • Shape: Straight, not branched.
    • Nuclei: Many, located on the periphery.
    • Striations: Skeletal and cardiac muscles have striations (stripes visible under a microscope), whereas smooth muscles do not.

Conclusion

  • Muscles have varying similarities and differences:
    • Skeletal & Cardiac: Both are striated.
    • Cardiac & Smooth: Both are involuntary.
    • Each muscle type has unique characteristics and functional roles in the body.