Psychology study guide ch.2

Psychology study guide ch.2 - Chapter 2 Neuron and Its...

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Chapter 2 Neuron and Its Parts Neuron: Individual nerve cell; 100 billion in brain Soma: Cell body; body of the neuron. Receives messages and sends messages down axon Axon: Fiber that carries information away from the cell body of a neuron Axon terminals: Branches that link the dendrites and somas of other neurons Dendrites: Receive messages from other neurons The Nerve Impulse Resting potential: Electrical charge of an inactive neuron Threshold: Trigger point for a neuron’s firing Action Potential: Nerve impulse More on Nerves Ion channels: Tiny openings through the axon membrane Negative after-potential: A drop in electrical charge below the resting potential Synapse: Microscopic space between two neurons over which messages pass Saltatory Conduction Process by which nerve impulses conducted down the axons of neurons coated with myelin jump from gap to gap in the myelin layer Myelin: A fatty layer coating some axons Neurotransmitters Chemicals that alter activity in neurons; brain chemicals Receptor site: Area on the surface of neurons and other cells that is sensitive to neurotransmitters or hormones Types of Neurotransmitters Acetylcholine: Activates muscles Dopamine: Muscle control Serotonin: Mood and appetite control Neural Regulators Neuropeptides: Regulate activity of other neurons Enkephalins: Relieve pain and stress; similar to endorphins Endorphins: Released by pituitary gland; also help to relieve pain Placebos raise endorphin levels Neuroplasticity Capacity of our brains to change in response to experience Neural Networks Central nervous system (CNS): Brain and spinal cord Peripheral nervous system: All parts of the nervous system outside of the brain and spinal cord Nerves and Neurons (cont) Neurilemma: Thin layer of cells wrapped around axons outside brain and spinal cord; forms a tunnel that damaged fibers follow as they repair themselves
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Two Divisions of the Peripheral Nervous System Somatic System: Carries messages to and from skeletal muscles and sense organs; controls voluntary behavior Autonomic System: Serves internal organs and glands; controls automatic functions such as heart rate and digestion pressure Two Divisions of the Autonomic Nervous System Sympathetic: Arouses body; emergency system Parasympathetic: Quiets body; most active after an emotional event The Spinal Cord Spinal Nerves: 31 of them; carry sensory and motor messages to and from the spinal cord Cranial Nerves: 12 pairs that leave the brain directly; also work to communicate
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Psychology study guide ch.2 - Chapter 2 Neuron and Its...

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