When you turn on your carâs heater, the hot coolant flows from the engine to the heater core, which is located inside the carâs dash. A fan (the same one used by the air conditioner) blows air through the heater core, with the heated air then passing through the carâs vents and warming the interior. The Controls.
presynaptic neuron. Definitions: 1. a neuron from the axon terminal of which an electrical impulse is transmitted across a synaptic cleft to the cell body or one or more dendrites of a postsynaptic neuron by the release of a chemical neurotransmitter.The definition information for presynaptic neuron is provided by Stedman's.You can search our medical dictionary here. Stedman's, part of Lippincott Williams & Wilkins, provides a comprehensive line of health-science publications for healthcare professionals and medical students.he definition information for presynaptic neuron is provided by Stedman's. You can search our medical dictionary here. Stedman's, part of Lippincott Williams & Wilkins, provides a comprehensive line of health-science publications for healthcare professionals and medical students.
As in the sympathetic nervous system, efferent parasympathetic nerve signals are carried from the central nervous system to their targets by a system of two neurons. The first neuron in this pathway is referred to as the preganglionic or presynaptic neuron. The parasympathetic ganglion where these preganglionic neurons synapse will be close to the organ of innervation. 2  This differs from the sympathetic nervous system, where synapses between pre-and post-ganglionic efferent nerves in general occur at ganglia that are farther away from the target organ.