The Muscular System Overview

Introduction

• The muscular system consists of over 600 muscles.
• This overview focuses on:
  • Main functions of the muscular system
  • Five major properties
  • Five types of muscle movements
  • Three types of muscles

Primary Purpose

• 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 nerves.
2. Contractable
   • Can contract or shorten after receiving stimulation.
3. Extensible
   • Can be stretched without damage.
4. Elasticity
   • Can return to original shape and length after being extended or contracted.
5. Adaptable
   • Can change in response to use (hypertrophy with increased work, atrophy with lack of work).

Types of Muscle Movements

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

Types of Muscles

1. Cardiac Muscle
   • Involuntary and forms the walls of the heart.
   • Contracts to circulate blood.
2. Visceral (Smooth) Muscle
   • Involuntary and found in organ systems like digestive or respiratory.
3. Skeletal Muscle
   • Voluntary and attaches to the skeleton to enable movement.
   • Requires conscious effort to move.

Supportive Structures

• Tendons
  • Attach muscles to bones.
• Fascia
  • Connect muscles to other muscles.
• Work with muscles to create movement.

Role of the Nervous System

• Essential for voluntary skeletal muscles.
• Severed communication results in paralysis (e.g., quadriplegic).
• Cardiac muscle is not directly dependent on the nervous system.

Conclusion

• Basic understanding of the muscular system, its properties, and functions.
• Future videos will cover topics like major muscle groups and common diseases.