Respiratory Physiology – Correct Pairs

Which of the following pair(s) related to respiratory physiology is/are correctly matched?

Correct Answer: All the above — all three pairs are correctly matched

Surfactant-Secreting Cells

• Mammals: Type II pneumocytes (Type II alveolar cells) secrete DPPC/Dipalmitoyl lecithin.
• Birds: Granular cells secrete surfactant.

Dorsal Respiratory Group (DRG)

• Located in dorsal medulla oblongata.
• Primarily responsible for inspiration and generating the basic rhythm of breathing.

Summary of Respiratory Centres

• DRG (dorsal medulla) → Inspiration (primary)
• VRG (ventral medulla) → Expiration (forced)
• Pneumotaxic centre (upper pons) → Terminates inspiration
• Apneustic centre (lower pons) → Deep inspiration

Bird vs. Mammal Respiration

• Birds have no diaphragm; both inspiration and expiration are active.
• In mammals, expiration is passive; inspiration is active.
• Birds have 9 air sacs (not 9 pairs). Birds have lungs + 9 air sacs (2 cervical, 2 anterior thoracic, 2 posterior thoracic, 2 abdominal, 1 unpaired clavicular).
• Site of gas exchange in birds: Parabronchi (tertiary bronchi), NOT air sacs (air sacs are avascular).