PC1001 Lecture Notes - Lecture 8: Autonomic Nervous System, Neuroglia, Action Potential
Document Summary
Large, fast myelinated breif arp (most sensory and motor neurons). Smaller, medium myelinated (visceral sensory and stage 1 autonomic nervous system). Smallest, slow unmyelinated, long arp (pain and temp sensory conduction and some ans stage 2 outputs). A synapse is the junction between neurons or between a neuron and an effector. Gap junctions connect cells and allow the transfer of information to synchronise the activity of a group of cells (very fast). One-way transfer of information from a presynaptic neuron to a postsynaptic neuron (or neuron to muscle cell). Works in same general way as neuron-neuron synapse, aim is to cause contraction of a muscle cell. Organophosphates: inactive ach-esterase (break down of ach), used in nerve gases (to kill via what mechanism), and in for example, insect repellents. A postsynaptic neuron can receive many signals at once. Neurotransmitters at chemical synapses cause either an excitatory or inhibitory graded potential.
