How do parasympathetic neural signals affect the working of the heart?
Correct answer: A. Reduce both heart rate and cardiac output
- A. Reduce both heart rate and cardiac output
- B. Heart rate is increased without affecting the cardiac output
- C. Both heart rate and cardiac output increase
- D. Heart rate decreases but cardiac output increases
Explanation
Parasympathetic neural signals, mediated by the vagus nerve (cranial nerve X), exert an inhibitory influence on the heart. During parasympathetic stimulation, the heart rate decreases (bradycardia) as the sinoatrial (SA) node's firing rate is reduced. This leads to fewer contractions per minute and consequently lowers cardiac output, which is determined by heart rate and stroke volume. Therefore, the correct answer is that both heart rate and cardiac output are reduced. The other options are incorrect as they do not accurately describe the effects of parasympathetic stimulation on the heart.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Coordination and Control
Coordination depends on receptors, neurons, synapses and nerve impulses, with reflex actions traced through the reflex arc and the roles of major brain regions. Chemical coordination covers endocrine glands and hormones, including how hormones regulate growth, metabolism, reproduction and internal balance, unlike rapid nervous control.
Practise Coordination and Control
1,687 free Coordination and Control MCQs from Biology, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Biology questions like this
Biology is on 8 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.