| A | B |
|---|
| acetylcholine | most common neurotransmitters either depolarizing or hyperpolarizing the membrane |
| action potential | rapid change in the membrane potential of an excitable cell |
| Alzheimer’s disease | age-related dementia |
| aspartate | amino acid that functions as a CNS neurotransmitter |
| astrocyte | glial cell that provides structural and metabolic support for neurons |
| autonomic nervous system | subdivision of the motor nervous system of vertebrates that regulates the internal environment |
| axon | carries nerve impulses away from the cell body toward target cells |
| axon hillock | conical region of a neuron’s axon where it joins the cell body |
| basal nuclei | cluster of nuclei deep within the white matter of the cerebrum |
| biogenic amine | neurotransmitter derived from an amino acid. |
| biological clock | controls an organism’s biological rhythms |
| bipolar disorder | depressive mental illness characterized by swings of mood from high to low |
| blood-brain barrier | estricts the passage of most substances into the brain |
| brainstem | functions in homeostasis coordination of movement and conduction of information to higher brain centers |
| cell body | part of a cell such as a neuron that houses the molecules |
| central canal | narrow cavity in the center of the spinal cord that is continuous with the fluid-filled ventricles of the brain |
| central nervous system (CNS) | the brain and spinal cord |
| cerebellum | functions in unconscious coordination of movement and balance |
| cerebral cortex | surface of the cerebrum |
| cerebral hemisphere | right or left side of the vertebrate brain |
| cerebrospinal fluid | blood-derived fluid that surrounds protects against infection nourishes |
| cerebrum | integrating center for memory learning emotions and other highly complex functions of the central nervous system |
| corpus callosum | connect the right and left cerebral hemispheres in placental mammals |
| cranial nerve | nerve that leaves the brain and innervates an organ of the head or upper body |
| dendrite | convey nerve impulses toward the cell body |
| depolarization | inside of the cell is made less negative relative to the outside than at the resting membrane potential |
| dopamine | biogenic amine closely related to epinephrine and norepinephrine |
| effector cell | muscle cell or gland cell that performs the body’s responses to stimuli |
| endorphin | inhibits pain perception |
| enteric division | complex networks of neurons in the digestive tract |
| epinephrine | mediates fight-or-flight responses to short-term stress |
| epithalamus | contains several clusters of capillaries that produce cerebrospinal fluid |
| equilibrium potential (Eion) | magnitude of a cell’s membrane voltage at equilibrium |
| excitatory postsynaptic potential (EPSP) | makes it more likely for a postsynaptic neuron to generate an action potential |
| forebrain | develops into the thalamus hypothalamus and cerebrum |
| gamma aminobutyric acid (GABA) | amino acid that functions as a CNS neurotransmitter |
| ganglion | cluster (functional group) of nerve cell bodies |
| gated ion channel | gated channel for a specific ion |
| glia | supporting cells that are essential for the structural integrity of the nervous system |
| glutamate | amino acid that functions as a CNS neurotransmitter |
| glycine | amino acid that functions as a CNS neurotransmitter |
| graded potential | local voltage change in a neuron membrane induced by stimulation of a neuron |
| gray matter | regions of dendrites and clusters of neuron cell bodies within the CNS |
| growth cone | responsive region at the leading edge of a growing axon |
| hindbrain | develops into the medulla oblongata pons and cerebellum |
| hyperpolarization | electrical state whereby the inside of the cell is made more negative relative to the outside |
| hypothalamus | functions in maintaining homeostasis |
| inhibitory postsynaptic potential (IPSP) | makes it more difficult for a postsynaptic neuron to generate an action potential |
| interneuron | nerve cell within the central nervous system that forms synapses with sensory and motor neurons |
| lateralization | segregation of functions in the cortex of the left and right hemispheres of the brain |
| ligand-gated ion channel | protein pore in the plasma membrane that opens or closes in response to a chemical signal |
| limbic system | interact with the cerebral cortex in determining emotions |
| long-term memory | ability to hold associate and recall information over one’s life |
| long-term potentiation (LTP) | enhanced responsiveness to an action potential (nerve signal) by a receiving neuron |
| major depression | depressive mental illness characterized by experiencing a low mood most of the time |
| medulla oblongata | controls autonomic homeostatic functions including breathing heart and blood vessel activity swallowing digestion and vomiting |
| membrane potential | charge difference between a cell’s cytoplasm and the extracellular fluid |
| midbrain | develops into sensory integrating and relay centers that send sensory information to the cerebrum |
| motor neuron | nerve cell that transmits signals from the brain or spinal cord to muscles or glands |
| myelin sheath | insulating coat of cell membrane from Schwann cells that is interrupted by nodes of Ranvier |
| neocortex | outermost region of the cerebral cortex |
| nerve cord | ropelike bundle of neuron fibers (axons and dendrites) tightly wrapped in connective tissue |
| nerve net | weblike system of neurons characteristic of radially symmetrical animals such as Hydra |
| neuron | fundamental unit of the nervous system |
| neuropeptide | relatively short chain of amino acids that serves as a neurotransmitter |
| neurotransmitter | chemical messenger released from the synaptic terminal of a neuron at a chemical synapse that diffuses across the synaptic cleft |
| norepinephrine | hormone that is chemically and functionally similar to epinephrine |
| oligodendrocyte | glial cell that forms insulating myelin sheaths around the axons of neurons in the central nervous system |
| parasympathetic division | generally enhances body activities that gain and conserve energy |
| Parkinson’s disease | motor disorder caused by a progressive brain disease and characterized by difficulty in initiating movements |
| peripheral nervous system (PNS) | sensory and motor neurons that connect to the central nervous system |
| pons | regulating the breathing centers in the medulla |
| postsynaptic cell | target cell at a synapse |
| presynaptic cell | transmitting cell at a synapse |
| radial glia | supporting cells that form tracks along which newly formed neurons migrate from the neural tube |
| reflex | automatic reaction to a stimulus |
| refractory period | short time immediately after an action potential in which the neuron cannot respond to another stimulus |
| resting potential | membrane potential characteristic of a nonconducting excitable cell |
| reticular formation | system of neurons containing over 90 separate nuclei that passes through the core of the brainstem |
| saltatory conduction | apid transmission of a nerve impulse along an axon resulting from the action potential jumping from one node of Ranvier to another |
| schizophrenia | severe mental disturbance characterized by psychotic episodes |
| Schwann cell | glial cells that forms insulating myelin sheaths around the axons of neurons in the peripheral nervous system |
| sensory neuron | nerve cell that receives information from the internal and external environments |
| serotonin | biogenic amine synthesized from the amino acid tryptophan |
| short-term memory | ability to hold information anticipations or goals for a time and then release them if they become irrelevant |
| somatic nervous system | composed of motor neurons that carry signals to skeletal muscles in response to external stimuli. |
| spatial summation | membrane potential of the postsynaptic cell is determined by the combined effect of EPSPs or IPSPs produced nearly simultaneously by different synapses |
| spinal nerve | nerve that carries signals to or from the spinal cord |
| stretch-gated ion channel | pore in a cell’s plasma membrane that opens when the membrane is mechanically deformed |
| substance P | neuropeptide that is a key excitatory signal that mediates our perception of pain |
| suprachiasmatic nuclei (SCN) | pair of structures in the hypothalamus of mammals that functions as a biological clock |
| sympathetic division | generally increases energy expenditure and prepares the body for action |
| synapse | locus where one neuron communicates with another neuron in a neural pathway |
| synaptic cleft | A narrow gap separating the synaptic knob of a transmitting neuron from a receiving neuron or an effector cell |
| synaptic terminal | bulb at the end of an axon in which neurotransmitter molecules are stored and released |
| synaptic vesicle | Membranous sac containing neurotransmitter molecules at the tip of the presynaptic axon |
| temporal summation | membrane potential of the postsynaptic cell in a chemical synapse is determined by the combined effect of EPSPs or IPSPs produced in rapid succession |
| thalamus | relay neural input to specific areas in the cerebral cortex and regulate what information goes to the cerebral cortex |
| threatened species | species that is considered likely to become endangered in the foreseeable future |
| threshold | potential an excitable cell membrane must reach for an action potential to be initiated |
| ventricle | space in the vertebrate brain |
| voltage-gated ion channel | specialized ion channel that opens or closes in response to changes in membrane potentia |
| white matter | Tracts of axons within the CNS |
