Crash Course: AP Psychology The Chemical Mind - Neurons or nerve cells are the building blocks that comprise our nervous systems. - Neurons share the same basic makeup as our other cells, but they have electrochemical that transmits messages to other neurons. - Humans have different types of neurons, Bipolar (interneuron), unipolar (sensory neuron), multipolar (motor neuron), and pyramidal cell. - All nerves share the same three basic parts: the soma (cell body), dendrites and axon . - The soma , or cell body, is basically the neuron’s life support; it contains all the necessary cell action like the nucleus, DNA, mitochondria, ribosomes, etc. If the soma dies, the whole neuron dies too. (Google Definition: Soma is the cell body of a neuron and contains the nucleus of the cell. The soma doesn’t play an active role in transmitting neural signals but keeps the cell functioning and holds the cell’s DNA.) - The dendrites , as bushy and brank-like as the trees they’re named after, receive messages from other cells. They’re the listeners, whispering what they hear back to the soma. (Google Definition: Segments of a neuron that receive stimulation in order for the cell to become active. They conduct electrical messages to the neuron cell body for the cell to function.) - The axon is the talker. They’re long, cable-like extension transmits electrical impulses from the cell body out to other neurons or glands or muscles. Depending on the type of neuron it is, it is sometimes encased in a protective layer of fatty tissue, called the myelin sheath. It’s almost like an insulated electrical wire the myelin sheath speeds up the transmission of messages,
and if it degrades, as it does with those affected with multiple sclerosis (a chronic, typically progressive disease involving damage to the sheaths of nerve cells in the brain and spinal cord.) (Google Definition: A long, slender projection of a nerve cell, or neuron, that typically conducts electrical impulses away from the neuron’s cell body. Myelinated axons are known as nerve fibers. The function of the axon is to transmit information to different neurons, muscles, and glands.) - Neurons transmit signals when stimulated by sensory input or triggered by neighboring neurons. - The dendrites pick up the signal and activate the neuron’s action potential or firing impulse, that shoots an electrical charge down the axon to its terminals and towards the neighboring neurons. - The contact points between neurons are called synapses . All those bushy little dendrites are decorated with synapses that almost but don’t quite touch the neighboring axon. - The microscopic gap is called the synaptic gap .
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- Fall '17