An increase in the level of carbon dioxide in the blood will result in a(n):

Correct Answer: B

Rationale: The correct answer is B: an increase of the respiratory rate. When carbon dioxide levels rise in the blood, it triggers the body to increase the rate of breathing to eliminate excess carbon dioxide through exhalation. This is known as the respiratory drive, controlled by the respiratory centers in the brainstem. Increasing the respiratory rate helps to restore the balance of gases in the blood. Incorrect Choices: A: Decrease in the rate of breathing - This is incorrect because high levels of carbon dioxide would stimulate an increase in breathing rate, not a decrease. C: Decrease of pulmonary ventilation - This is incorrect as an increase in carbon dioxide would typically lead to an increase, not a decrease, in pulmonary ventilation. D: Decrease of the alveolar ventilation rate - This is incorrect because an increase in carbon dioxide would prompt an increase in alveolar ventilation to remove excess carbon dioxide from the blood.

Correct Answer: C

Rationale: The correct answer is C because the pneumotaxic center in the pons modifies the rate and depth of breathing by sending inhibitory signals to the dorsal respiratory group in the medulla, which controls inspiration and expiration. It does not set the at-rest respiratory pattern like option A, prolong inspiration like option B, or suppress the expiratory center in the medulla like option D. This center plays a crucial role in fine-tuning breathing patterns to maintain appropriate oxygen levels in the body.

Correct Answer: A

Rationale: The function of the conchae in the nasal cavity is to increase surface area. By increasing the surface area of the nasal cavity, conchae help to humidify, filter, and warm the air entering the respiratory system. This ensures optimal conditions for efficient gas exchange in the lungs. Choice B (exchange gases) is incorrect because gas exchange primarily occurs in the alveoli of the lungs, not in the nasal cavity. Choice C (maintain surface tension) is incorrect as surface tension is typically associated with liquid interfaces, not with the nasal cavity. Choice D (maintain air pressure) is also incorrect because the conchae do not play a direct role in maintaining air pressure within the nasal cavity.

Correct Answer: D

Rationale: The correct answer is D: cuneiform. The cuneiform cartilages are paired cartilages, not unpaired. The epiglottis, cricoid, and thyroid cartilages are unpaired cartilages of the larynx. The epiglottis functions in covering the larynx during swallowing, the cricoid provides support for the larynx, and the thyroid cartilage forms the "Adam's apple." The cuneiform cartilages, on the other hand, are small paired cartilages located within the aryepiglottic folds. They help maintain the shape and stiffness of these folds, assisting in vocal cord function.

Correct Answer: C

Rationale: The correct answer is C: Nasopharynx. The Eustachian tube connects the middle ear to the nasopharynx, allowing for pressure equalization. The oropharynx (A) and laryngopharynx (B) do not directly receive the Eustachian tube. Choice D is incorrect as the Eustachian tube does connect to a specific part of the pharynx.