Transport in Human - In-depth Notes

Transport in Human

  • Heart Structure

    • Atria and Ventricles
    • Atria have thinner walls than ventricles.
      • Atria only pump blood a short distance to the ventricles.
    • Ventricles have thicker walls for powerful contractions needed to pump blood further.
      • Left ventricle pumps blood to the body; hence has thicker walls.
      • Right ventricle pumps blood to the lungs.

  • Heart Function

    • Main function: Pump blood throughout the body.
    • Blood flow process:
    1. Muscles of the atria contract, pushing blood into the ventricles.
    2. Ventricles then contract, sending blood into arteries (aorta and pulmonary artery).
    3. Valves: Ensure one-way blood flow and prevent backflow.

  • Investigating Heart Rate and Physical Activity

    • Steps for Investigation:
    1. Measure pulse rate for one minute at rest using a stopwatch.
    2. Perform 2 minutes of exercise (e.g., running on the spot).
    3. Sit down and measure pulse rate for one minute again.
    • Expected Outcome: Pulse rate increases during exercise due to higher demand for oxygen and glucose by muscles for respiration.

  • Coronary Arteries

    • Supply food and oxygen to heart muscle.

  • Coronary Heart Disease (CHD)

    • Definition: Blockage of coronary arteries caused by deposition of fatty substances.
    • Risk Factors/Causes:
    1. Unbalanced diet high in fats; can cause blockage in arteries.
    2. Stress leads to increased blood pressure.
    3. Smoking: nicotine and carbon monoxide contribute to blood clotting.
    4. Age and Gender: Risk increases with age; males are at a higher risk.
    5. Genetic predisposition can increase risk of developing CHD.
    6. Sedentary lifestyle: Lack of exercise slows blood flow, promoting fat deposits.
    • Risk Reduction Strategies:
    • Maintain a healthy, balanced diet.
    • Reduce intake of animal fats.
    • Engage in regular exercise to improve blood flow.