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
- Excitable/Irritable
- Capable of receiving and responding to stimulation from the nerves.
- Contractable
- Capable of contracting or shortening after receiving stimulation.
- Extensible
- Can be stretched without damage by the application of force.
- Elasticity
- Able to return to original resting shape and length after being extended or contracted.
- Adaptability
- Can change in response to use (hypertrophy with increased work, atrophy if deprived of use).
Five Types of Muscle Movements
- Adduction
- Moving a body part toward the midline of the body.
- Abduction
- Moving a body part away from the body.
- Flexion
- Bending a joint to decrease the angle between two bones or body parts.
- Extension
- Straightening a joint to increase the angle between two bones or body parts.
- Rotation
- Moving a body part around an axis.
Three Types of Muscles
- Cardiac Muscle
- Involuntary muscle that operates without conscious control; forms the walls of the heart and circulates blood.
- Visceral (Smooth) Muscle
- Involuntary muscle found in organs (e.g., digestive and respiratory systems).
- Skeletal Muscle
- Voluntary muscles attached to the skeleton for movement; requires conscious effort to move.
Supportive Structures
- Tendons
- 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.