BISC 101 Lecture Notes - Lecture 21: Parasympathetic Nervous System, Sympathetic Nervous System, Schwann Cell

• School: Simon Fraser University
• Department: Biological Sciences
• Course: BISC 101
• Professor: Tony Williams

Document Summary

Sensory and muscle systems: dendrites: collect electrical signals, cell body: sends signal to axon, axon: sends to another dendrite or effector cell. Microglia: role in immune function in cns: resting state, na+/k+ channels closed, depolarisation, na+ channels open, rising phase, depolarisation reaches threshold, all na+ channels open, falling phase (hyperpolarization, na channels close, k channels open, k goes in. Myelinated axons wrapped in schwann cells(glial) (increase speed of action potential) Charge jumps from node of ranvier (fast conductance=saltatory conductance) Transmission of nerve impulse at synapse: ap depolarises presynaptic membrane, ca channels open, synaptic vesicles move to fuse with presynaptic membrane, releasing neurotransmitter into synaptic cleft, neurotransmitter binds to ligand-gated ion channels on postsynaptic membrane. Epsp: make action potentials more likely in postsynaptic cells. Ipsp: make action potentials less likely in postsynaptic cells. Sympathetic nervous system: increase heartbeat, inhibit activity of stomach. Parasympathetic nervous system: decrease heartbeat, stimulate activity of stomach.