Muscular System Overview

Integumentary, Skeletal, and Muscular Systems

Muscular System Functions (6.3.1)

• Main Functions: Movement, posture maintenance, heat production.

Types of Muscle Tissue (6.3.2)

1. Characteristics:

• Skeletal Muscle: Striated, voluntary, attached to bones.
• Cardiac Muscle: Striated, involuntary, found in the heart.
• Smooth Muscle: Non-striated, involuntary, lining internal organs.

2. Comparison:

• Striation:
  • Skeletal: Yes
  • Cardiac: Yes
  • Smooth: No
• Location:
  • Skeletal: Attached to bones
  • Cardiac: Heart
  • Smooth: Internal organs

Sliding Filament Theory (6.3.3)

• Muscle contraction occurs when myosin filaments pull actin filaments toward the center of the sarcomere, leading to muscle shortening.

Muscle Metabolism (6.3.4)

• Aerobic Respiration: The process used for ATP production when sufficient oxygen is available during normal exercise.
• Anaerobic Respiration: Utilized during intense exercise when oxygen levels are low, leading to lactic acid production.
• Lactic Acid Dynamics: Increases during intense exercise due to anaerobic conditions; decreases post-exercise as oxygen becomes available to metabolize lactic acid.

Muscle Fiber Types (6.3.5)

Characteristics:

• Slow Twitch: Darker in color, more myoglobin, suited for endurance activities, fatigue resistant.
• Fast Twitch: Lighter in color, less myoglobin, suited for short bursts of strength, fatigue easily.

Examples:

• Marathon Runner: Primarily slow twitch muscles.
• Weightlifter: Primarily fast twitch muscles.
• Sprinter (100m): Fast twitch muscles.
• Long-distance Swimmer: Slow twitch muscles.