The Bronchial tree is connected with the brain by

Correct Answer: D

Rationale: The correct answer is D: Vagus nerve. The vagus nerve is responsible for controlling the bronchial tree's smooth muscle and gland secretions, regulating breathing. It innervates the lungs and plays a crucial role in the parasympathetic control of the respiratory system. The other options (A: Trochlear nerve, B: Trigeminal nerve, C: Phrenic nerve) are not connected to the bronchial tree or involved in respiratory control.

Correct Answer: C

Rationale: The correct answer is C because mast cells release histamine and heparin during an inflammatory response. Histamine causes vasodilation and increased vascular permeability, leading to redness and swelling. Heparin prevents blood clotting to allow immune cells to reach the site of infection. Choices A and B are incorrect because red blood cells do not release pyrogens, and T cells release cytokines, not interferon, in response to infection. Choice D is incorrect because immunosuppressants like cortisone would dampen the immune response rather than trigger an inflammatory response.

Correct Answer: C

Rationale: Step 1: The movement labeled '2' is inhalation. Step 2: During inhalation, the diaphragm contracts and moves downward. Step 3: This creates more space in the thoracic cavity, allowing the lungs to expand and fill with air. Step 4: Therefore, the correct answer is C: diaphragm contracts produces the movement labeled '2'. Summary: Choice A and B are incorrect because the rectus abdominis is not directly involved in inhalation. Choice D is incorrect because the diaphragm needs to contract to create the necessary space for inhalation.

Correct Answer: D

Rationale: The correct answer is D because a higher PO2 gradient between alveoli and blood promotes greater oxygen binding to hemoglobin in the lungs. A high PCO2 (choice A) would actually decrease oxygen binding, while a slightly acidic pH (choice B) can affect oxygen dissociation but not loading. Having a PO2 of about 70 mm Hg (choice C) is not optimal for maximum loading as it is lower than what is typically found in the alveoli during normal breathing.

Correct Answer: C

Rationale: The correct answer is C because the Dorsal Respiratory Group (DRG) is involved in both inspiration and expiration, not just forced breathing. During quiet breathing, the DRG primarily controls inspiration, while the Ventral Respiratory Group (VRG) primarily controls expiration. In forced breathing, both the DRG and VRG are activated to increase respiratory effort. Choice A and B are both true statements as the DRG controls inspiration and the VRG controls expiration. Choice D is incorrect as the VRG is involved in both quiet and forced breathing, not just forced breathing.