What is the relationship between the pressures at label '3'?

Correct Answer: B

Rationale: The correct answer is B because at label '3', the pressure outside the system is higher than the pressure inside. This is based on the principle that pressure decreases with increasing elevation. As we move upward in a fluid column, the pressure decreases. Therefore, in this scenario, the pressure outside the system (higher elevation) will be greater than the pressure inside the system (lower elevation). A: P outside = P inside - Incorrect, as explained above, pressures are not equal at label '3'. C: P outside < P inside - Incorrect, pressures are not in this relationship at label '3'. D: P outside + P inside - Incorrect, this is not a valid comparison of pressures at label '3'.

Correct Answer: B

Rationale: The correct answer is B: more intense inhalation. The apneustic center is responsible for prolonging inhalation by stimulating the inspiratory neurons in the medulla oblongata. When the apneustic center is stimulated, it disrupts the normal breathing pattern, causing a prolonged and more intense inhalation. This results in deeper and more forceful breaths. Incorrect choices: A: increased respiratory rate - Stimulation of the apneustic center would not lead to an increased respiratory rate, but rather to changes in the depth and intensity of inhalation. C: a shorter respiratory cycle - The apneustic center's stimulation does not lead to a shorter respiratory cycle, but rather to a prolonged inhalation phase. D: less activity in the DRG center - The dorsal respiratory group (DRG) is responsible for initiating inspiration, and the apneustic center does not affect its activity.

Correct Answer: B

Rationale: The correct answer is B: fissure. A fissure is a deep groove or division that separates the lung into lobes. Each lung has fissures that divide it into lobes: the right lung has an oblique fissure and a horizontal fissure, while the left lung has an oblique fissure. The mediastinum (A) is the central compartment of the thoracic cavity. The root (C) is the area where structures such as blood vessels and bronchi enter or exit the lung. The pleura (D) is a membrane that covers the lungs but does not separate them into lobes.

Correct Answer: C

Rationale: The correct answer is C: Pulmonary lobule. A pulmonary lobule is the portion of the lung ventilated by one bronchiole. This is because each bronchiole branches into smaller airways ending in clusters of alveoli called pulmonary lobules. The other choices are incorrect because: A) Terminal bronchioles are the smallest airways in the respiratory tract, not the portion of the lung ventilated by one bronchiole. B) Bronchiole tree is not a specific anatomical term. D) Primary bronchioles are the branches of the main bronchi and are not associated with the specific portion of the lung ventilated by one bronchiole.

Correct Answer: B

Rationale: The correct answer is B because it correctly lists the branches of the bronchial tree in order: trachea-primary bronchi-secondary bronchi-tertiary bronchi-bronchioles-terminal. The trachea divides into the primary bronchi, which further divide into secondary bronchi, followed by tertiary bronchi, bronchioles, and finally terminal bronchioles. Choice A is incorrect because it lists "primary bronchi_trachea" which is out of order and "tertiary_bronchioles" instead of "tertiary bronchi." Choice C is incorrect because it combines the incorrect order of branches from both A and B. Choice D, "itis," is not a valid term related to the branches of the bronchial tree.