Anatomy and Physiology Learning Aim B

Unit 1: Anatomy and Physiology Learning Aim B - Effects of Exercise on Muscular System

Assessment Criteria

  • Characteristics and Functions of Different Muscle Types

  • Major Skeletal Muscles

  • Antagonistic Muscle Pairs

  • Types of Skeletal Muscle Contraction

  • Fibre Types

  • Responses of the Muscular System to a Single Sport or Exercise Session

  • Adaptations of the Muscular System to Exercise

  • Additional Factors Affecting the Muscular System

Types of Muscle

  • Cardiac Muscle

    • Found only in heart walls.

    • Involuntary muscle, with its own blood supply.

    • Specialised striated tissue that contracts quickly without fatigue.

    • Function: Pumps blood throughout the body.

  • Skeletal Muscle

    • Also known as striated or striped muscle.

    • Voluntary muscle, conscious control over movements.

    • Connected to the skeletal system via tendons, responsible for movement.

    • Can become fatigued during prolonged activity.

    • Function: Facilitates voluntary movement.

  • Smooth Muscle

    • Involuntary muscle controlled by the nervous system.

    • Slow contractions, non-striated appearance under the microscope.

    • Located in walls of blood vessels and digestive systems.

    • Function: Regulates digestion & blood pressure.

Major Skeletal Muscles

  • Deltoids

  • Biceps

  • Triceps

  • Wrist flexors and extensors

  • Supinators & Pronators

  • Pectorals

  • Abdominals

  • Obliques

  • Quadriceps

  • Hip flexors

  • Tibialis anterior

  • Erector spinae

  • Trapezius

  • Latissimus dorsi

  • Gluteals

  • Hamstrings

  • Gastrocnemius

  • Soleus

Muscle Characteristics

  • Origin: The fixed end of the muscle that remains stationary.

  • Insertion: The end of the muscle that moves, typically crosses a joint.

Antagonistic Muscle Pairs

  • Muscles function in pairs (agonist and antagonist), where:

    • Agonist: Contracts to perform a movement.

    • Antagonist: Relaxes to allow the movement to occur.

  • Example Pairs:

    • Biceps / Triceps

    • Deltoids / Latissimus Dorsi

    • Pectorals / Trapezius

Types of Muscle Contractions

  1. Concentric: Muscle shortens as it contracts.

    • Example: Bicep curl (lifting phase).

  2. Eccentric: Muscle lengthens as it contracts, promoting muscle strength and size.

    • Example: Bicep curl (lowering phase).

  3. Isometric: Muscle length does not change, joint angle remains constant.

    • Example: Plank hold.

Muscle Fiber Types

  • Type I (Slow Twitch)

    • Slow contraction, resistant to fatigue, suited for endurance activities (e.g., marathons).

  • Type IIa (Fast Twitch)

    • Faster contraction, moderately resistant to fatigue, suited for middle-distance events (400/800m).

  • Type IIx (Fast Twitch)

    • Rapid contraction, fatigues quickly, suited for high-intensity, short-duration activities (100m sprints).

Responses of the Muscular System to Exercise

  • Increased Blood Supply: Enhances oxygen delivery and metabolic activity.

  • Increased Muscle Temperature: Raises energy production and reduces injury risk.

  • Increased Muscle Pliability: Enhances flexibility, reduces injury chances.

  • Lactate Build-Up: Common in anaerobic exercise, leads to rapid fatigue.

  • Microtears: Result from resistance training, associated with DOMS (Delayed Onset Muscle Soreness).

Adaptations of the Muscular System to Exercise

  • Hypertrophy: Muscle fibers increase in size due to resistance training.

  • Increased Tendon Strength: Regular exercise enhances tendon flexibility and strength.

  • Increase in Myoglobin Storage: More myoglobin can store oxygen, enhancing endurance.

  • Increase in Mitochondria: Larger and more numerous mitochondria enhance aerobic energy production.

  • Increased Storage of Glycogen & Fat: Improves energy availability during extended activities.

  • Lactate Tolerance: Enhanced ability to manage lactic acid buildup during exercise.

Additional Factors Affecting the Muscular System

  • Age: Muscle mass decreases with age (sarcopenia).

  • Cramping: Involuntary contractions can occur due to dehydration or overuse.

Prevention of Cramps

  • Hydration: Maintain proper fluid intake during exercise.

  • Stretching: Increases flexibility and reduces cramp risk.

Conclusion

Understanding the muscular system and its responses to exercise is crucial for optimizing performance and preventing injuries. Proper training can lead to significant adaptations that enhance strength, endurance, and overall muscular health.