Transport in Animals - Part 1

Introduction

• IGCSE Study Buddy: Platform for revising Cambridge IGCSE Biology.
• Chapter 9 (Part 1): Focus on transport in animals.

Single Circulatory System (Fish)

• General Structure: Blood vessels, pump (heart), valves.
• Fish Heart: Two chambers (Atrium and Ventricle).
• Blood Flow:
  • Blood passes through the heart once per circuit.
  • Oxygenated blood (pink arrows) and deoxygenated blood (blue arrows).
• Gills: Location of oxygen absorption.
• Circulation Types:
  • Gill Circulation: Blood to gills for oxygenation.
  • Systemic Circulation: Oxygenated blood to body, returns deoxygenated.

Double Circulatory System (Mammals)

• Heart Structure: Four chambers.
• Blood Flow:
  • Blood passes through the heart twice per circuit.
  • Deoxygenated Blood Path:
    • Enters right atrium via vena cava.
    • Right ventricle pumps it to the lungs via pulmonary artery.
    • Becomes oxygenated at lungs.
  • Oxygenated Blood Path:
    • Enters left atrium via pulmonary vein.
    • Left ventricle pumps it to the body via aorta.
• Circulation Types:
  • Pulmonary Circulation: Blood to lungs.
  • Systemic Circulation: Blood to body.

Advantages of Double Circulation

• More efficient delivery of oxygen and glucose.
• Maintains higher blood pressure compared to single circulation.

Structures of the Mammalian Heart

• Right Atrium (RA): Receives deoxygenated blood from the body.
  • Vena Cava: Veins bringing blood.
  • Tricuspid Valve: Atrioventricular valve, prevents backflow.
• Right Ventricle (RV): Pumps deoxygenated blood to lungs.
  • Semilunar Valve: Prevents backflow into the heart.
  • Pulmonary Artery: Carries blood to lungs.
• Septum: Separates left and right sides, prevents blood mixing.
• Left Atrium (LA): Receives oxygenated blood from lungs.
  • Pulmonary Vein: Veins bringing oxygenated blood.
  • Bicuspid Valve: Atrioventricular valve, prevents backflow.
• Left Ventricle (LV): Pumps oxygenated blood to the body.
  • Semilunar Valve: Prevents backflow into the heart.
  • Aorta: Carries blood to the body.

Summary of Blood Flow

• Deoxygenated Path:
  • Right Atrium → Right Ventricle → Pulmonary Artery → Lungs.
• Oxygenated Path:
  • Pulmonary Vein → Left Atrium → Left Ventricle → Aorta → Body.

Tip

• Remember: Arteries (A for Away) carry blood away from the heart.
• Vessels: Arteries (exit), veins (enter).

Coronary Arteries

• Function: Supply oxygen-rich blood to the heart muscle.
• Wrap Around: The outside of the heart.

Heart Muscle Walls

• Ventricles: Thicker than atria to pump blood out.
• Left Ventricle: Thicker than right ventricle, pumps blood to the whole body.

Monitoring Heart Activity

• Tools: ECG, pulse rate, stethoscope (valve sounds).

Effect of Physical Activity on Heart Rate

• Experiment Steps:
  • Measure resting pulse rate for a minute.
  • Exercise, record pulse every minute until resting rate returns.
• Observation: Heart rate increases during exercise, decreases after.
• Reason: Increased oxygen and glucose demand, waste removal.

Coronary Heart Disease (CHD)

• Cause: Blockage of coronary arteries.
• Results: Oxygen starvation, heart attack.
• Risk Factors:
  • Diet: High saturated fats.
  • Lack of Exercise: Leads to high cholesterol.
  • Diabetes & Obesity: Higher risk.
  • Stress: Increases blood pressure.
  • Smoking: Increases blood pressure and clots.
  • Genetics: Family history.
  • Age: Increased risk with age.
  • Gender: Higher in males.
• Prevention: Quit smoking, healthy diet, regular exercise.

Conclusion

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