How do parasympathetic neural signals affect the working of the heart? [2014]
Reduce both heart rate and cardiac output.
Heart rate is increased without affecting the cardiac output.
Both heart rate and cardiac output increase.
Heart rate decreases but cardiac output increases.
(1)
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.
Cardiac activities of the heart are regulated by:
A. Nodal tissue
B. A special neural centre in the medulla oblongata
C. Adrenal medullary hormones
D. Adrenal cortical hormones
Choose the correct answer from the options given below : [2025]
A, B and C Only
A, B, C and D
A, C and D Only
A, B and D Only
(1)
Normal cardiac activities of the heart are regulated intrinsically, i.e., auto regulated by specialised muscles (nodal tissue), hence the heart is called myogenic. A special neural centre in the medulla oblongata can moderate the cardiac function through autonomic nervous system.
Sympathetic nervous system can increase the rate of heartbeat, ventricular contraction and thereby cardiac output.
Parasympathetic neural signals decrease the rate of heartbeat, speed of conduction of action potential and thereby the cardiac output. Adrenal medullary hormones can also increase the cardiac output.
