Lecture on Oxygen and Respiration

Introduction

• Oxygen Requirement: All members of the kingdom Animalia require oxygen for energy production.
• Cellular Respiration: The process that keeps us alive, byproduct is CO2.
• CO2 Disposal: Important to expel CO2 as it has no benefit to our bodies.

Respiratory and Circulatory Systems

• Function: Bring in oxygen through lungs, circulate to cells via heart and arteries, collect CO2 with veins, and expel it through lungs.

Oxygen Intake Without Lungs

• Simple Diffusion: Some animals (e.g., arthropods, amphibians) can intake oxygen through wet membranes or skin.
• Limitations of Diffusion: Larger animals and warm-blooded animals require more oxygen and hence have lungs.

Function of Lungs

• Oxygen-Dissolving Membranes: Lungs have moist membranes with large surface areas (~75 sq meters) for oxygen absorption.
• Structure: Involves bronchioles leading to alveoli where gas exchange occurs.

Process of Breathing

• Inhalation & Exhalation: Oxygen enters during inhalation, CO2 exits during exhalation.
• Diaphragm's Role: Contracts to allow lung expansion and air intake.

Circulatory System Function

• Blood Flow: Oxygenated blood from heart to body, deoxygenated blood back to the heart.

Heart's Role

• Structure: Four-chambered heart (left ventricle, aorta, arteries, capillaries, veins).
• Pressure System: Blood flows due to pressure gradients.

Blood Pathway

• Veins & Arteries: Arteries carry blood away from the heart, veins bring it back.
• Oxygen Exchange: Occurs in alveoli through capillaries.

Differences with Ectotherms

• Metabolic Rate: Endotherms have higher metabolism needing more oxygen.
• Heart Chambers: Complexity increases with more chambers (fish - 2, reptiles/amphibians - 3, mammals/birds - 4).

Conclusion

• Energy Source: Energy to power diaphragm and heart comes from the digestive system, which will be discussed next.
• Engagement: Encouraged to ask questions and engage on social media.