5 Steps to a 5 AP Psychology, 2010-2011 Edition - Laura Lincoln Maitland [46]
Broca’s area—located in left frontal lobe, controls production of speech.
Temporal lobes—primary area for hearing, understanding language (Wernicke’s area), understanding music/tonality, processing smell.
Wernicke’s area—located in left temporal lobe, plays role in understanding language and making meaningful sentences.
Aphasia—impairment of the ability to understand or use language.
Glial cells—supportive cells of the nervous system that guide the growth of developing neurons, help provide nutrition for and get rid of wastes of neurons, and form an insulating sheath around neurons that speeds conduction.
Neuron—the basic unit of structure and function of your nervous system. Neurons perform three major functions: receive information, process it, and transmit it to the rest of your body.
• Cell body—also called the cyton or soma; the part of the neuron that contains cytoplasm and the nucleus, which directs synthesis of such substances as neurotransmitters.
• Dendrites—branching tubular processes of neuron that have receptor sites for receiving information.
• Axon—a long, single conducting fiber extending from the cell body of a neuron that transmits an action potential and that branches and ends in tips called terminal buttons (a.k.a. axon terminals, or synaptic knobs), which secrete neurotransmitters.
• Myelin sheath—a fatty covering of the axon made by glial cells, which speeds up conduction of the action potential.
• Terminal buttons (a.k.a. axon terminals, end bulbs, or synaptic knobs)—tips at the end of axons that secrete neurotransmitters when stimulated by the action potential.
Neurotransmitters—chemical messengers released by the terminal buttons of the presynaptic neuron into the synapse.
• Acetylcholine (ACh)—a neurotransmitter that causes contraction of skeletal muscles, helps regulate heart muscles, is involved in memory, and also transmits messages between the brain and spinal cord. Lack of ACh is associated with Alzheimer’s disease.
• Dopamine—a neurotransmitter that stimulates the hypothalamus to synthesize hormones and affects alertness, attention, and movement. Lack of dopamine is associated with Parkinson’s disease; too much is associated with schizophrenia.
• Glutamate—a neurotransmitter that stimulates cells throughout the brain, but especially in the hypothalamus, and is associated with memory formation and information processing.
• Serotonin—a neurotransmitter associated with arousal, sleep, appetite, moods, and emotions. Lack of serotonin is associated with depression.
• Endorphin—a neurotransmitter similar to the opiate morphine that relieves pain and may induce feelings of pleasure.
• Gamma-aminobutyric acid (GABA)—a neurotransmitter that inhibits firing of postsynaptic neurons. Huntington’s disease and seizures are associated with malfunctioning GABA systems.
Action potential—also called an impulse, the “firing” of a neuron; a net flow of sodium ions into the cell that causes a rapid change in potential across the membrane when stimulation reaches threshold.
All-or-none principle—the law that the neuron either generates an action potential when the stimulation reaches threshold or doesn’t fire when stimulation is below threshold. The strength of the action potential is constant whenever it occurs.
Nodes of Ranvier—spaces between segments of myelin on the axons of neurons.
Saltatory conduction—rapid conduction of impulses when the axon is myelinated since depolarizations jump from node (of Ranvier) to node.
Synapse—region of communication between the transmitting presynaptic neuron and receiving postsynaptic neuron, muscle, or gland, consisting of the presynaptic terminal buttons, a tiny space and receptor sites typically on the postsynaptic dendrites.
Excitatory neurotransmitter—chemical secreted at terminal button that causes the neuron on the other side of the synapse to generate an action potential (to fire).