HSC 240 Exam 2 Study Notes

HSC 240 Exam 2 Study Notes

Exam Information

• Subject: HSC 240 (Human Physiology)
• Format: Multiple Choice
• Instructions: Select the BEST answer from the options provided for each question.

Major Topics Covered

1. Neural Adaptations to Anaerobic Training

• Question 1: Which of the following are primary neural adaptations to anaerobic training?
  • A. Decreased firing rates and alterations to selective recruitment
  • B. Increased neural drive and reductions in inhibitory mechanisms
  • Correct Answer: Increased neural drive refers to the enhanced ability of the nervous system to activate muscles, leading to improved strength and power output. Reductions in inhibitory mechanisms, such as the Golgi tendon reflex, facilitate this process by allowing greater muscle contraction.
  • C. Decreased neuromuscular junction size and increased firing rates
  • D. Lowered EMB at maximal force output and decreased reflex potentiation

2. Muscle Growth Mechanisms

• Question 2: The enlargement of muscle fiber cross-sectional area, and the number of muscle fibers via longitudinal fiber splitting is defined as:
  • A. Muscle density; hyperplasia
  • B. Hypertrophy; hyperplasia
  • Correct Answer: Hypertrophy is the increase in the size of muscle fibers, while hyperplasia refers to the increase in the number of muscle fibers.
  • C. Hypertrophy; muscle density
  • D. Hyperplasia; hypoplasia

3. Muscle Fiber Recruitment During Exercise

• Question 3: When performing box-to-box plyometric jumps (a high-intensity, explosive power exercise), which muscle fibers are bypassed through the principle of selective recruitment?
  • A. Type I (slow-twitch) fibers
  • B. Type IIa (fast-twitch oxidative) fibers
  • C. Type IIx (fast-twitch glycolytic) fibers
  • Correct Answer: Type IIx fibers are typically recruited for their capacity for high force production, and selective recruitment allows for optimized performance by prioritizing these high-threshold motor units during explosive activities.
  • D. Type IIc (intermediate) fibers

4. Regulation of Stroke Volume

• Question 4: Stroke volume is regulated by which of the following mechanisms?
  • A. End-systolic volume and skeletal muscle pump
  • B. Skeletal muscle pump and systolic volume
  • C. End-diastolic volume and catecholamines
  • Correct Answer: End-diastolic volume (the volume of blood in the ventricles at the end of filling) influences stroke volume according to the Frank-Starling mechanism, and catecholamines (e.g., adrenaline) increase heart contractility, thereby enhancing stroke volume.
  • D. Catecholamines and systolic volume

5. Determining Cardiac Output

• Question 5: Which of the following are used to determine cardiac output?
  • A. Stroke volume and heart rate
  • Correct Answer: Cardiac output is calculated as the product of stroke volume (the amount of blood ejected from the heart per beat) and heart rate (the number of beats per minute), expressed as:
    $\text{Cardiac Output (Q)} = \text{Stroke Volume (SV)} \times \text{Heart Rate (HR)}$
  • B. Stroke volume and rate-pressure product
  • C. Heart rate and diastolic blood pressure
  • D. Rate-pressure product and diastolic blood pressure

Conclusive Summary

• The notes encapsulate the essential concepts surrounding neural adaptations to anaerobic training, mechanisms of muscle growth, and factors influencing stroke volume and cardiac output, important for understanding human physiology in the context of exercise science. Each question enhances comprehension of the cardiovascular and muscular responses during physical activity, crucial for students preparing for practical applications in kinesiology and health sciences.