NEET · Biology · STD 11 - 15. Body fluids and criculations

How do parasympathetic neural signals affect the working of the heart?

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.

Verified Solution

Answer & Solution

Correct Answer

(A) Reduce both heart rate and cardiac output.

Step-by-step Solution

Detailed explanation

(a) : A special neural centre in medulla oblongata can moderate the cardiac function through autonomic nervous system \((ANS)\). Neural signals through the sympathetic nerves (part of \(ANS\)) can increase the rate of heart beat, the strength of ventricular contraction and thereby the cardiac output. Parasympathetic neural signals (component of \(ANS\)) decrease the rate of heart beat, speed of conduction of action potential and thereby the cardiac output.

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Match List \(I\) with List \(II\) :

List \(I\) (Sub Phases of Prophase \(I\))	List \(II\)
(A) Diakinesis	(I) Synaptonemal complex formation
(B) Pachytene	(II) Completion of terminalisation of chiasmata
(C) Zygotene	(III) Chromosomes look like thin threads
(D) Leptotene	(IV) Appearance of recombination nodules

Choose the correct answer from the options given below

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