BIL 150 Lecture Notes - Lecture 22: Squid Giant Axon, Peripheral Nervous System, Schwann Cell
Document Summary
Many different types of nervous systems tough. Common pathway: the reflex arc--brain not involved. Not really integration: just like a wire diagram . Muscle output only: no direct brain input. Cell body similar to other cells; cytoplasm, organelles, Dendrites: carry stimuli/signals into the cell body. Axon: single outgrowth; carry signals to next neuron. Can attach to the synapse of another cell. Information transferred from presynaptic cell to postsynaptic cell. Na ions can only enter at nodes: allows for saltatory conduction (node to node) Membrane depolarization (via nodes/saltatory conduction) allows for the signal molecules (neurotransmitters) to travel to synaptic knob. Neurotransmitters chemically diffuse from presynaptic membrane to post synaptic membrane. Resting potential: characteristic electric charge; when cells are at rest. Measure with oscilloscope because very small quantities. One electrode into cell, one electrode outside cell. Ex: squid giant axon sga: -65 to -70 mivolts. Charge difference due to unequal distribution of ions across neuronal membranes.
