Introduction to Muscular System Functions

Aug 29, 2024

Overview of the Muscular System

The muscular system is composed of over 600 muscles. This lecture covers:

  • Main functions of the muscular system
  • Five major properties of muscles
  • Five types of muscle movements
  • Three types of muscles
  • Interaction of muscles and the nervous system

Primary Purpose of the Muscular System

  • Provides movement for the body.
  • Muscles receive their ability to move through the nervous system.

Five Major Properties of Muscles

  1. Excitable/Irritable
    • Capable of receiving and responding to stimulation from the nerves.
  2. Contractable
    • Capable of contracting or shortening after receiving stimulation.
  3. Extensible
    • Can be stretched without damage by the application of force.
  4. Elasticity
    • Able to return to original resting shape and length after being extended or contracted.
  5. Adaptability
    • Can change in response to use (hypertrophy with increased work, atrophy if deprived of use).

Five Types of Muscle Movements

  1. Adduction
    • Moving a body part toward the midline of the body.
  2. Abduction
    • Moving a body part away from the body.
  3. Flexion
    • Bending a joint to decrease the angle between two bones or body parts.
  4. Extension
    • Straightening a joint to increase the angle between two bones or body parts.
  5. Rotation
    • Moving a body part around an axis.

Three Types of Muscles

  1. Cardiac Muscle
    • Involuntary muscle that operates without conscious control; forms the walls of the heart and circulates blood.
  2. Visceral (Smooth) Muscle
    • Involuntary muscle found in organs (e.g., digestive and respiratory systems).
  3. Skeletal Muscle
    • Voluntary muscles attached to the skeleton for movement; requires conscious effort to move.

Supportive Structures

  • Tendons
    • Attach muscles to bones.
  • Fascia
    • Connects muscles to other muscles.
  • Tendons and fascia work with muscles to create the muscular system necessary for movement.

Nervous System Connection

  • The nervous system is intrinsically connected to the muscular system and is essential for voluntary skeletal muscles.
  • If communication from the nervous system is severed, skeletal muscles cannot produce movement, leading to paralysis (e.g., quadriplegia).
  • The cardiac muscle is the only muscle not directly dependent on the nervous system.

Conclusion

  • This introduction provides a basic understanding of the muscular system's properties and functions.
  • For more in-depth study, look for future videos covering major muscle groups and common diseases/conditions related to the muscular system.