Heart Physiology in Mammals and Birds

Introduction

• Efficient oxygen delivery is crucial for organisms with high metabolic rates.
• Mammals and birds have evolved specialised circulatory systems to meet their oxygen demands efficiently.

The Circulatory System

• The circulatory system consists of the heart, blood vessels, and blood, while the respiratory system includes the lungs (in mammals) or respiratory structures (in birds).
• Together, these systems ensure the delivery of oxygen to respiring tissues.

Main Blood Vessels

Blood vessels play a critical role in circulation:

• Arteries: Carry blood away from the heart under high pressure.
• Capillaries: The smallest blood vessels where nutrient and gas exchange occurs between the blood and body tissues.
• Veins: Transport blood back to the heart under low pressure.

The Heart

The heart comprises two types of chambers: atria and ventricles.

• Atria: Receive blood entering the heart.
• Ventricles: Pump blood out of the heart.

Metabolic Rates

Different organisms have varying metabolic rates:

• Mammals and birds have high metabolic rates.
• Reptiles and amphibians exhibit moderate metabolic rates.
• Fish have relatively low metabolic rates.

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Heart Physiology in Mammals and Birds

Circulation in Mammals and Birds

• Mammals and birds have a complete double circulatory system:
  • Oxygenated and deoxygenated blood flow separately within the heart.
  • There is no mixing of oxygenated and deoxygenated blood.
  • Blood leaving the heart is rich in oxygen.
  • This efficient separation allows for the high-energy demands of mammals and birds.

Advantages of Double Circulatory System

• The double circulatory system offers several advantages:
  • Efficient oxygen supply to tissues.
  • Supports the high metabolic rates of mammals and birds.
  • Enables sustained physical activity and energy-intensive processes.