BIO 121 Lecture Notes - Lecture 10: Adrenal Medulla, High Energy Stereoscopic System, Substantia Nigra
Document Summary
Network of specialized cells (neurons) that transmit signals along dedicated pathways. Glial cells: nourish neurons, insulate the axons, and regulate the extracellular fluid surrounding neurons: outnumber neurons. Peripheral nervous system (pns): neurons that carry info in and out of the cns. Neuron - structural and functional unit of the nervous system. The neuron"s nucleus is located in the cell body. Near its end, axons divide into several branches, each of which ends in a synaptic terminal. The site of communication between a synaptic terminal and another cell is called a synapse. At most synapses, information is passed from the transmitting neuron (the presynaptic cell) to the receiving cell (the postsynaptic cell) by means of chemical messengers called neurotransmitters. Nodes of ranvier: gaps in myelin sheath in which action potentials are not generated. Saltatory conduction: propagating action potentials at only specific points in the axon.