BIOB34H3 Chapter : BIOB30 Ch8 (273-end)
Document Summary
The specificity of neural communication depends on several factors: the signal molecules secreted by the neurons, the target cell receptors for these chemicals, the anatomical connections between neurons and their targets (occur at synapses) Each synapse has two parts: the presynaptic cell"s axon terminal, the postsynaptic cell"s membrane. In a neural reflex, information moves from the presynaptic to postsynaptic cell: the postsynaptic cell isn"t always a neuron, in most neuron-to-neuron synapses, the axon terminal is next to the dendrites or cell body of the postsynaptic neuron. Cells average 10,000 synapses (can be more than 150000) Electrical synapses pass an electrical signal or current directly from the cytoplasm of one cell to another through gap junctions: rectifying synapse gap junctions in which current can only flow in one direction. Occur mainly in cns neurons: also found in glial cells, cardiac and smooth muscle, and in nonexcitable cells that use electrical signals.
