In an introduction to lung physiology, respiratory physiology is primarily the study of which process?

• A. How the heart generates electrical impulses and pumps blood through systemic and pulmonary circuits
• B. How the kidneys regulate blood volume and electrolyte balance through filtration and reabsorption
• C. How skeletal muscle fibers generate force through actin-myosin cross-bridge cycling
• D. How gases (O2 and CO2) are ventilated, exchanged, transported, and used by the body to maintain acid-base homeostasis

Answer: (D)

Verified step by step guidance

1. Step 1: Identify the main focus of respiratory physiology, which is the study of the respiratory system and its functions.
2. Step 2: Understand that respiratory physiology primarily involves the processes related to gases, specifically oxygen (O2) and carbon dioxide (CO2).
3. Step 3: Recognize the key processes in respiratory physiology: ventilation (movement of air in and out of the lungs), gas exchange (between alveoli and blood), gas transport (via the bloodstream), and cellular use of gases.
4. Step 4: Connect these processes to the maintenance of acid-base homeostasis, which is the regulation of blood pH through the balance of CO2 and bicarbonate.
5. Step 5: Conclude that respiratory physiology is not about heart function, kidney function, or muscle contraction, but about how gases are ventilated, exchanged, transported, and utilized to maintain homeostasis.