1. Which of the following muscles is primarily responsible for pulmonary ventilation? A) Diaphragm B) External intercostals C) Sternocleidomastoid D) Pectoralis minor Answer: A) Diaphragm Rationale: The diaphragm is the main muscle involved in breathing. It contracts and flattens to increase the volume of the thoracic cavity, allowing air to enter the lungs. 2. During an asthma attack, which of the following changes occurs in the respiratory system? A) Decreased airway resistance B) Increased tidal volume C) Bronchoconstriction D) Decreased dead space volume Answer: C) Bronchoconstriction Rationale: Asthma attacks are characterized by bronchoconstriction, where the airways narrow, increasing resistance to airflow and making breathing difficult. 3. What is the primary function of the type II alveolar cells in the lungs? A) Gas exchange B) Production of surfactant C) Transport of oxygen D) Phagocytosis of pathogens Answer: B) Production of surfactant Rationale: Type II alveolar cells are responsible for the production of surfactant, a substance that reduces surface tension within the alveoli and prevents their collapse. 4. Which part of the brain primarily regulates the respiratory rate? A) Cerebrum B) Medulla oblongata C) Pons