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| One of the most common neurotransmitters; functions by binding to receptors and altering the permeability of the postsynaptic membrane to specific ions, either depolarizing or hyperpolarizing the membrane. |
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| A rapid change in the membrane potential of an excitable cell, caused by stimulus-triggered, selective opening and closing of voltage-sensitive gates in sodium and potassium ion channels. |
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| An age-related dementia (mental deterioration) characterized by confusion, memory loss, and other symptoms. |
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| A glial cell that provides structural and metabolic support for neurons. |
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| A typically long extension, or process, from a neuron that carries nerve impulses away from the cell body toward target cells. |
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| Depressive mental illness characterized by swings of mood from high to low; also called manic-depressive disorder. |
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| A specialized capillary arrangement in the brain that restricts the passage of most substances into the brain, thereby preventing dramatic fluctuations in the brain’s environment. |
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| Collection of structures in the adult brain, including the midbrain, the pons, and the medulla oblongata; functions in homeostasis, coordination of movement, and conduction of information to higher brain centers. |
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| The part of a cell, such as a neuron, that houses the molecules. |
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| central nervous system (CNS) |
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| In vertebrate animals, the brain and spinal cord. |
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| Part of the vertebrate hindbrain located dorsally; functions in unconscious coordination of movement and balance. |
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| The surface of the cerebrum; the largest and most complex part of the mammalian brain, containing sensory and motor nerve cell bodies of the cerebrum; the part of the vertebrate brain most changed through evolution. |
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| Blood-derived fluid that surrounds, protects against infection, nourishes, and cushions the brain and spinal cord. |
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| The dorsal portion of the vertebrate forebrain, composed of right and left hemispheres; the integrating center for memory, learning, emotions, and other highly complex functions of the central nervous system. |
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| The thick band of nerve fibers that connect the right and left cerebral hemispheres in placental mammals, enabling the hemispheres to process information together. |
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| One of usually numerous, short, highly branched processes of a neuron that convey nerve impulses toward the cell body. |
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| An electrical state in an excitable cell whereby the inside of the cell is made less negative relative to the outside than at the resting membrane potential. A neuron membrane is depolarized if a stimulus decreases its voltage from the resting potential of -70 mV in the direction of zero voltage. |
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| A muscle cell or gland cell that performs the body’s responses to stimuli; responds to signals from the brain or other processing center of the nervous system. |
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| Any of several hormones produced in the brain and anterior pituitary that inhibits pain perception. |
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| A brain region, derived from the diencephalon, that contains several clusters of capillaries that produce cerebrospinal fluid. |
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| One of three ancestral and embryonic regions of the vertebrate brain; develops into the thalamus, hypothalamus, and cerebrum. |
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| A cluster (functional group) of nerve cell bodies in a centralized nervous system. |
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| Supporting cells that are essential for the structural integrity of the nervous system and for the normal functioning of neurons. |
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| Regions of dendrites and clusters of neuron cell bodies within the CNS. |
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| One of three ancestral and embryonic regions of the vertebrate brain; develops into the medulla oblongata, pons, and cerebellum. |
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| An electrical state whereby the inside of the cell is made more negative relative to the outside than at the resting membrane potential. A neuron membrane is hyperpolarized if a stimulus increases its voltage from the resting potential of -70 mV, reducing the chance that the neuron will transmit a nerve impulse. |
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| The ventral part of the vertebrate forebrain; functions in maintaining homeostasis, especially in coordinating the endocrine and nervous systems; secretes hormones of the posterior pituitary and releasing factors that regulate the anterior pituitary. |
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| An association neuron; a nerve cell within the central nervous system that forms synapses with sensory and motor neurons and integrates sensory input and motor output. |
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| A protein pore in the plasma membrane that opens or closes in response to a chemical signal, allowing or blocking the flow of specific ions. |
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| A group of nuclei (clusters of nerve cell bodies) in the lower part of the mammalian forebrain that interact with the cerebral cortex in determining emotions; includes the hippocampus and the amygdala. |
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| The lowest part of the vertebrate brain, commonly called the medulla; a swelling of the hindbrain dorsal to the anterior spinal cord that controls autonomic, homeostatic functions, including breathing, heart and blood vessel activity, swallowing, digestion, and vomiting. |
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| The charge difference between a cell’s cytoplasm and the extracellular fluid, due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances. |
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| One of three ancestral and embryonic regions of the vertebrate brain; develops into sensory integrating and relay centers that send sensory information to the cerebrum. |
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| A nerve cell that transmits signals from the brain or spinal cord to muscles or glands. |
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| In a neuron, an insulating coat of cell membrane from Schwann cells that is interrupted by nodes of Ranvier, where saltatory conduction occurs. |
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| A ropelike bundle of neuron fibers (axons and dendrites) tightly wrapped in connective tissue. |
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| A nerve cell; the fundamental unit of the nervous system, having structure and properties that allow it to conduct signals by taking advantage of the electrical charge across its cell membrane. |
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| A chemical messenger released from the synaptic terminal of a neuron at a chemical synapse that diffuses across the synaptic cleft and binds to and stimulates the postsynaptic cell. |
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| A type of glial cell that forms insulating myelin sheaths around the axons of neurons in the central nervous system. |
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| A motor disorder caused by a progressive brain disease and characterized by difficulty in initiating movements, slowness of movement, and rigidity. |
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| peripheral nervous system (PNS) |
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Definition
| The sensory and motor neurons that connect to the central nervous system. |
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| Portion of the brain that participates in certain automatic, homeostatic functions, such as regulating the breathing centers in the medulla. |
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| An automatic reaction to a stimulus, mediated by the spinal cord or lower brain. |
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| The short time immediately after an action potential in which the neuron cannot respond to another stimulus, owing to an increase in potassium permeability. |
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| The membrane potential characteristic of a nonconducting, excitable cell, with the inside of the cell more negative than the outside. |
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| Rapid transmission of a nerve impulse along an axon, resulting from the action potential jumping from one node of Ranvier to another, skipping the myelin-sheathed regions of membrane. |
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| Severe mental disturbance characterized by psychotic episodes in which patients lose the ability to distinguish reality from hallucination. |
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| A type of glial cells that forms insulating myelin sheaths around the axons of neurons in the peripheral nervous system. |
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| A nerve cell that receives information from the internal and external environments and transmits the signals to the central nervous system. |
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| The locus where one neuron communicates with another neuron in a neural pathway; a narrow gap between a synaptic terminal of an axon and a signal-receiving portion (dendrite or cell body) of another neuron or effector cell. Neurotransmitter molecules released by synaptic terminals diffuse across the synapse, relaying messages to the dendrite or effector. |
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Definition
| One of two integrating centers of the vertebrate forebrain. Neurons with cell bodies in the thalamus relay neural input to specific areas in the cerebral cortex and regulate what information goes to the cerebral cortex. |
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| The potential an excitable cell membrane must reach for an action potential to be initiated. |
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| A space in the vertebrate brain, filled with cerebrospinal fluid. |
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| voltage-gated ion channel |
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Definition
| A specialized ion channel that opens or closes in response to changes in membrane potential. |
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| Tracts of axons within the CNS. |
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