Parasympathetic (vagal) nerves leave the vagal nuclei within the medulla as preganglionic efferent vagal fibers. These preganglionic efferent fibers are relatively long and do not synapse until they reach their target organ (e.g., the heart).
medical Definition of isovolumetric : of, relating to, or characterized by unchanging volume; especially: relating to or being an early phase of ventricular systole in which the cardiac muscle exerts increasing pressure on the contents of the ventricle without significant change in the muscle fiber length and the ventricular volume remains constant
Adiabatic process - a process with no heat transfer into or out of the system. Isochoric process - a process with no change in volume, in which case the system does no work. Isobaric process - a process with no change in pressure. Isothermal process - a process with no change in temperature.