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🔬 Biology  ·  Breathing and Exchange of Gases  ·  NEET

The pleural membrane that directly covers the lung surface is the:

Answer: Visceral pleura.

  • A Pericardium
  • B Parietal pleura
  • C Visceral pleura
  • D Peritoneum

Correct answer: C. Visceral pleura

Explanation: The visceral pleura lines the lung surface itself, while the parietal pleura lines the inner wall of the thoracic cavity.

O₂-Haemoglobin Dissociation CurvepO₂% Hb saturatedresting curveshifted RIGHT (Bohr effect:↑CO₂, ↑H⁺, ↑temperature)Sigmoid shape = cooperative binding; right-shift means O₂ is released more easily in active tissue

The S-shaped (sigmoid) curve reflects cooperative binding between Hb's four O₂ sites; the Bohr effect shifts the whole curve to the right under conditions found in actively respiring tissue (more CO₂, more acid, more heat), making haemoglobin release oxygen more readily exactly where it's needed.

Concept context

The mechanics of breathing, lung volumes, gas transport in blood, the Bohr effect, and respiratory regulation.

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