PSYC 355 Chapter Notes - Chapter 5: Golgi Apparatus, Connexon, University Of Manchester
Document Summary
1920s - the 5msec problem. the speed of impulses down the axon from the receptor to the muscle was slower than expected. Otto loewi showed definitely that synaptic transmission between the nerves and the heart are chemically mediated. The heart has two types of innervation; one type speeds the beating of the heart, and the other slows it. The latter type of innervation is supplied by the vagus nerve. Loewi isolated a frog heart with the vagal innervation still intact, stimulated the nerve electrically, and observed the expected effect: the slowing of the heartbeat. The critical demonstration that this effect was chemically mediated came when he applied the solution that had bathed this heart to a second isolated frog heart and found that the beating of this one also slowed. The active compound, which loewi called vagusstoff (literally vagus substance in. As we see in this chapter, acetylcholine is also a transmitter at the synapse between nerve and skeletal muscle.
