Respiratory System - SS2 Biology Past Questions and Answers - page 2

Higher animals have diverse respiratory systems. Mammals have lungs with alveoli for efficient oxygen and carbon dioxide exchange. Birds have a unique air sac system that ensures continuous, unidirectional airflow through their lungs. Reptiles have lungs with varying degrees of folding and can supplement respiration through the use of their skin.

Plants have specialized structures for gas exchange. Stomata, small openings on leaves and stems, allow for the intake of carbon dioxide and the release of oxygen. Inside the leaves, intercellular air spaces facilitate gas diffusion and provide a large surface area for gas exchange, allowing plants to perform photosynthesis efficiently.

The human respiratory system is composed of several key organs. The lungs are the primary respiratory organs, containing bronchial tubes, bronchioles, and alveoli for gas exchange. The diaphragm, a dome-shaped muscle, contracts and relaxes to aid in inhalation and exhalation. The bronchial tree branches within the lungs to ensure air reaches all parts of the respiratory system. Together, these organs allow for efficient exchange of oxygen and carbon dioxide, maintaining homeostasis in the body.