PSYC 4140 Lecture Notes - Lecture 4: Axon Hillock, Axon Terminal, Schwann Cell
Document Summary
Temporal summation: adding up of electrical signals over time. Spatial summation: adding up of electrical signals over space. Axon hillock decides that electrical signal is enough to start an action potential which will go from axon to axon terminals, translating to the next neuron. *axons: long strip of myelin sheathed cells which carry action potential. *axon terminals: small swellings that release signals to affect other neurons. Chemical signals, known as neurotransmitters, cross small gaps, known as synapses. Estimated about 500 trillion synapses in human brain. *synapse: a connecting space between two axons neurotransmitter signal goes from axon terminal, into the synaptic space, which then interacts with receptors in neighboring axon. ***the neurotransmitters doesn"t enter the receptor ion channels, it works as a key to turn them on/off, allowing charged ion like potassium or sodium to move in/out of axons. Motor neurons carry information from the brain to the muscles. Interneurons convey the signals around the nervous system.