Before You Begin
Question #46383
The Question
A healthy individual rapidly ascends to a high altitude, leading to acute physiological hypoxia. During this state, the body must balance the demand for oxygen delivery against systemic blood pressure stability. Which of the following statements correctly describes the integrated neural regulation of cardiac activity in this scenario?
Options
- A.
Peripheral chemoreceptors in the carotid and aortic bodies trigger sympathetic-mediated tachycardia, which overrides the vagal bradycardia reflex normally initiated by baroreceptors.
- B.
Central chemoreceptors in the medulla detect the drop in arterial and stimulate the vasomotor center to induce parasympathetic bradycardia.
- C.
Carotid sinus baroreceptors prioritize blood pressure homeostasis by suppressing the chemoreceptor-induced sympathetic drive, resulting in a net decrease in cardiac output.
- D.
The drop in directly inhibits the sympathetic nerve fibers innervating the SA node, forcing the heart to rely solely on the Frank-Starling mechanism.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Baroreceptors|Chemoreceptors|Cardiac_Acceleratory_Center
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: The hierarchical integration of autonomic reflexes.
Students often learn the baroreceptor (blood pressure) and chemoreceptor (blood gas) reflexes in isolation.
The trap lies in predicting the outcome when these reflexes conflict.
The physiological rule is that metabolic survival (preventing tissue hypoxia via chemoreceptors) overrides mechanical homeostasis (blood pressure maintenance via baroreceptors).
Additionally, it tests the micro-terminology distinction between central chemoreceptors (insensitive to hypoxia) and peripheral chemoreceptors.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Body Fluids and Circulation - Class 11 |
| Concept | Regulation of Cardiac Activity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |