Vocabulary
Terms : Hide Images
| 4357798567 | Neuron | 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 plasma membrane. | 0 | |
| 4357798568 | Brain | Organ of the central nervous system where information is processed and integrated. | 1 | |
| 4357798569 | Ganglion (Ganglia) | A cluster (functional group) of nerve cell bodies in a centralized nervous system. | 2 | |
| 4357798570 | Sensory Neuron | A nerve cell that receives information from the internal or external environment and transmits signals to the central nervous system. | 3 | |
| 4357798571 | Interneuron | An association neuron; a nerve cell within the central nervous system that forms synapses with sensory and/or motor neurons and integrates sensory input and motor input. | 4 | |
| 4357798572 | Motor Neuron | A nerve cell that transmits signals from the brain or spinal cord to muscles or glands. | 5 | |
| 4357798573 | Central Nervous System (CNS) | Neurons that carry out integration are organized here. Includes the brain and a longitudinal nerve cord. | 6 | |
| 4357798574 | Peripheral Nervous System (PNS) | The sensory and motor neuron that connect to the central nervous system. | 7 | |
| 4357798575 | Dendrite | One of usually numerous short, highly branched extensions of a neuron that receive signals from other neurons. | 8 | |
| 4357798576 | Axon | A typically long extension, or process, of a neuron that carries nerve impulses away from the cell body toward target cells. | 9 | |
| 4357798577 | Axon Hillock | The conical region of a neuron's axon where it joins the cell body; typically the region where nerve impulses are generated. | 10 | |
| 4357798578 | Synapse | The junction where one neuron communicates with another cell across a narrow gap. Neurotransmitter molecules released by the neuron diffuse across the synapse, relaying messages to the other cell. | 11 | |
| 4357798579 | Synaptic Terminal | A bulb at the end of an axon in which neurotransmitter molecules are stored and from which they are released. | 12 | |
| 4357798580 | Neurotransmitter | A molecule that is released from the synaptic terminal of a neuron at a chemical synapse, diffuses across the synaptic cleft, and binds to the postsynaptic cell, triggering a response. | 13 | |
| 4357798581 | Presynaptic Cell | The transmitting cell at a synapse | 14 | |
| 4357798582 | Postsynaptic Cell | The target cell at a synapse. | 15 | |
| 4357798583 | Glia | Supporting cells that are essential for the structural integrity of the nervous system and for the normal functioning of neurons. | 16 | |
| 4357798584 | Membrane Potential | The difference in electrical charge (voltage) across a cell's plasma membrane, due to the differential distribution of ions. Membrane potential effects the activity of excitable cells and the transmembrane movement of all charged substances. | 17 | |
| 4357798585 | Resting Potential | The membrane potential characteristic of a nonconducting excitable cell, with the inside of the cell more negative than the outside. | 18 | |
| 4357798586 | Ion Channel | A transmembrane protein channel that allows a specific ion to flow across the membrane down its concentration gradient. | 19 | |
| 4357798587 | Equilibrium Potential | The magnitude of a cell's membrane voltage at equilibrium; calculated using the Nernst equation. | 20 | |
| 4357798588 | Gated Ion Channel | A gated channel for a specific ion. The opening or closing of such channels may alter the membrane potential. | 21 | |
| 4357798589 | Hyperpolarization | A change in a cell's membrane potential such that the inside of the membrane becomes more negative relative to the outside. hyperpolarization reduces the chance that a neuron will transmit a nerve impulse. | 22 | |
| 4357798590 | Depolarization | A change in a cell's membrane potential such that the inside of the membrane is made less negative relative to the outside. For example, a neuron membrane is depolarized if a stimulus decreases its voltage from the resting potential of -70 mV in the direction of zero voltage. | 23 | |
| 4357798591 | Voltage-Gated Ion Channel | A specialized ion channel that opens or closes in response to changes in membrane potential. | 24 | |
| 4357798592 | Action Potential | 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. | 25 | |
| 4357798593 | Threshold | The potential that an excitable cell membrane must reach for an action potential to be initiated. | 26 | |
| 4357798594 | Refractory Period | The short time immediately after an action potential in which the neuron cannot respond to another stimulus, owing to the inactivation of voltage-gated sodium channels. | 27 | |
| 4357798595 | Myelin Sheath | Around the axon of a neuron, an insulating coat of cell membranes from Schwann cells or oligodendrocytes. It is interrupted by nodes of Ranvier, where action potentials are generated. | 28 | |
| 4357798596 | Oligodendrocytes | A type of glial cell that forms insulating myelin sheaths around the axons of neurons in the central nervous system. | 29 | |
| 4357798597 | Schwann Cell | A type of glial cell that forms insulating myelin sheaths around the axons of neurons in the peripheral nervous system. | 30 | |
| 4357798598 | Node of Ranvier | Gap in the myelin sheath of certain axons where an action potential may be generated. In saltatory conduction, an action potential is regenerated. | 31 | |
| 4357798599 | Saltatory Conduction | 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. | 32 | |
| 4357798600 | Synaptic Vesicle | Membranous sac containing neurotransmitter molecules at the tip of an axon. | 33 | |
| 4357798601 | Synaptic Cleft | A narrow gap separating the synaptic terminal of a transmitting neuron from a receiving neuron or an effector cell. | 34 | |
| 4357798602 | Excitatory Postsynaptic Potential (EPSPs) | An electrical change (depolarization) in the membrane of a postsynaptic cell caused by the binding of an excitatory neurotransmitter from a presynaptic cell to a postsynaptic cell to generate an action potential. | 35 | |
| 4357798603 | Inhibitory Postsynaptic Potential (IPSPs) | An electrical change (usually hyperpolarization) in the membrane of a postsynaptic neuron caused by the binding of an inhibitory neurotransmitter from a presynaptic cell to a postsynaptic receptor; makes it more difficult for a postsynaptic neuron to generate an action potential. | 36 | |
| 4357798606 | Acetylcholine | 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. | 37 | |
| 4357798607 | Biogenic Amine | A neurotransmitter derived from an amino acid. | 38 | |
| 4357798608 | Serotonin | A neurotransmitter, synthesized from the amino acid tryptophan, that functions in the central nervous system. | 39 | |
| 4357798609 | Dopamine | A neurotransmitter that is a cetecholamine, like epinephrine and norepinephrine. | 40 | |
| 4357798610 | Epinephrine | A catecholamine that, when secreted as a hormone by the adrenal medulla, mediates "fight-or-flight" responses to short-term stresses; also released by some neurons as a neurotransmitter; also known as adrenaline. | 41 | |
| 4357798611 | Norepinephrine | A catecholamine that is chemically and functionally similar to epinephrine and acts as a hormone or neurotransmitter, also known as noradrenaline. | 42 | |
| 4357798612 | Gamma-Aminobutyric Acid (GABA) | An amino acid that functions as a CNS neurotransmitter in the central nervous system of vertebrates. | 43 | |
| 4357798613 | Glutamate | An amino acid that functions as a neurotransmitter in the central nervous system. | 44 | |
| 4357798614 | Neuropeptide | A relatively short chain of amino acids that serves as a neurotransmitter. | 45 | |
| 4357798616 | Endorphin | Any of several hormones produced in the brain and anterior pituitary that inhibits pain perception. | 46 |
