Does the parasympathetic nervous system have a large effect

Does the parasympathetic nervous system have a large effect on ventricular contractility? If so, what effect? If not, why not?

Solution

Answer=

The parasympathetic nervous system does not have a large effect on ventricular contractility

Acetylcholine is neurotransmitter of parasympathetic nervous system

is stored in vesicle & released by parasympathetic stimulation ,activating primarily postsynaptic muscarinic & preganglionic nicotinic receptors

Increased parasympathetic stimulation decreases heart rate by decreasing SA node discharge rate & AV node conduction velocity

Ventricular contractility is not affected by parasympathetic system when when background sympathetic discharge is low when but is enhanced in sympathetic activation