Term
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Definition
| The electrical signals used for long-distance communication in the nervous system. |
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Term
| Absolute Refractory period |
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Definition
| The period during which the neuron is functionally unable to generate a second spike, occurring early in the period of repolarization and afterhyperpolarization. |
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Term
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Definition
| Senses the transmembrane potential and can be opened by depolarization. |
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Term
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Definition
| Carry information towards the CNS. |
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Term
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Definition
| The main form of catecholamine released by the adult adrenal. Also called epinephrine. |
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Term
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Definition
| The chemical transmitter used by the preganglionic cells. |
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Term
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Definition
| Endocrine glands that could be thought of as modified sympathetic ganglia. |
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Term
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Definition
| The cranial nerve that innervates the muscle that abducts the eye. |
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Term
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Definition
| Central gray matter is shaped like a capital H and the horns are the arms of the H that project anteriorly. |
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Term
| Anterior spinocerebellar tracts |
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Definition
| Located within the spinocerebellar pathway, carrying information from muscle and joint receptors to the cerebellum. |
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Term
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Definition
| Smaller and less important fiber tracts that connect corresponding parts of the right and left halves of the CNS. |
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Term
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Definition
| Substances similar enough to the legitimate transmitter to activate the receptor. |
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Term
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Definition
| One of three membranes of connective tissue that surround the whole CNS, located between the dura mater and pia mater. |
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Term
| Alpha-Adrenergic receptors |
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Definition
| Receptors for norepinephrine and epinephrine. |
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Term
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Definition
| Fingerlike projections of the arachnoid that act as valves projecting through the dura into the dural blood sinuses. |
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Term
| Aterhyperpolarization phase |
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Definition
| A period during which the membrane potential is even more inside negative than at rest. |
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Term
| Beta-adrenergic receptors |
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Definition
| Receptors for norepinephrine and epinephrine. |
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Term
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Definition
| That part of the peripheral nervous system that supplies motor innervation to the viscera. |
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Term
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Definition
| A single tubular axon that sprouts from the cell body at a bump. Also called an initial segment. |
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Term
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Definition
| Now called basal nuclei, these are islands of neuronal cell bodies in the cerebral white matter. |
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Term
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Definition
| A class of glial cells in the CNS that control the composition and volume of the fluid microenvironment that surrounds central neurons. |
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Term
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Definition
| Structures that allow neurons to communicate with each other and with effectors. |
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Term
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Definition
| In the cerebral cortex, responsible for forming a unified picture of the sensory world, associating key elements of it with the resources of past experience, and formulating complex behaviors. |
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Term
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Definition
| A single tubular structure on the neuron cell body that conducts action potentials. |
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Term
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Definition
| Connects the third and fourth ventricle, running through the midbrain, dividing it into a dorsal tectum and paired ventral cerebral peduncles. |
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Term
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Definition
| Secreted by the choroid plexus, it circulates throughout the ventricles and the subarachnoidal space, providing a liquid cushion that gives some protection to the brain and spinal cord. |
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Term
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Definition
| Structures found in the fourth ventricle. |
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Term
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Definition
| The most common form of synapse in which the axon terminal releases a specific neurotransmitter chemical that acts on the plasma membrane of the target cell, either to excite or to inhibit electrical activity in the recipient cell. |
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Term
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Definition
| The central gray matter is shaped like a capital H. The crossbar of the H is the central commissure. |
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Term
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Definition
| The central gray matter is shaped like a capital H. The crossbar of the H is the central commissure and contains the hollow central canal. |
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Term
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Definition
| Islands of neuronal cell bodies in the cerebral white matter that are involved in the control of movement. |
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Term
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Definition
| Coordinates and smooth body movements, particularly rapid ones. |
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Term
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Definition
| Fiber tracts that connect corresponding parts of the right and left halves of the CNS. |
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Term
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Definition
| An Na+ channel state in which the pore is blocked by an internal activation gate that senses the transmembrane potential and can be opened by depolarization, switching the channel to the open state. |
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Term
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Definition
| A membrane attached to the roofs of the four ventricles that secretes CSF. |
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Term
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Definition
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Term
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Definition
| Several pathways, possibly carrying different types of information, may make synapses on the same neurons. |
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Term
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Definition
| The bulk of gray matter in the brain. |
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Term
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Definition
| A critical area located in only one hemisphere. |
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Term
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Definition
| Any change in the direction of a less-negative potential. |
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Term
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Definition
| A division of the prosencephalon vesicle, containing the thalamus and hypothalamus regions. |
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Term
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Definition
| Both sensory and motor pathways cross from one side of the CNS to the other before they enter or leave the brain. |
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Term
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Definition
| Stimulation of the dendrites results in a local depolarization that decreases in intensity as it travels through the dendrites to the cell body. |
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Term
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Definition
| Embedded within the cerebellum’s core of white matter. |
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Term
| Direct corticospinal pathway |
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Definition
| The pyramidal tracts that carry axons of neurons in the motor cortex that traverse the cord without synapsing until they reach neurons in the spinal segments. |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| Each spinal segment has a pair that project from the posterolateral surface on each side. |
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Term
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Definition
| A class of glial cells in the CNS. |
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Term
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Definition
| Carry commands to effectors. |
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Term
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Definition
| Contains the cell bodies of somatic sensory afferents. |
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Term
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Definition
| A pathway located in the posterior funiculus occupies a wedge-shaped sector of the medial posterior cord and carries information about fine touch and pressure sensations. |
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Term
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Definition
| Originate in brain stem nuclei that receive input from the basal nuclei and cerebellum, control mainly the muscles of the axial skeleton, and mediate less finely controlled movements of the trunk. |
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Term
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Definition
| Postsynaptic potentials that increase the likelihood that the postsynaptic cell will initiate an action potential at the axon hillock. |
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Term
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Definition
| Large parts of the temporal, parietal, and occipital lobes that appear to be critical for integrating multiple modes of sensory information into a comprehensive understanding of a situation. |
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Term
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Definition
| A membrane protein (short for GTP-binding protein) that consists of three subunits designated alpha, beta, and gamma. |
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Term
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Definition
| One of the principal diencephalic structures forming the roof of the third ventricle and containing the pineal gland. |
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Term
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Definition
| The hindbrain, connected to the third ventricle by the cerebral aqueduct. |
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Term
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Definition
| A sheath that encloses the entire peripheral nerve. |
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Term
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Definition
| A class of the somatic sensory system that includes touch, temperature, and pain that project from the body surface, as well as muscle, tendon, and joint receptors that give information about the position and movement of the body in space. |
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Term
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Definition
| Ridges that are created by folding of the cortex as it grows. |
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Term
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Definition
| Converts guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP). |
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Term
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Definition
| A medial spinal nerve branch that connects the base of each ventral ramus to a corresponding sympathetic chain ganglion, part of the sympathetic branch of the autonomic motor system. |
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Term
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Definition
| The supporting cells of the nervous system. |
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Term
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Definition
| The central matter of the spinal cord and much of the cortex. |
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Term
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Definition
| A cranial mixed nerve that serves part of the tongue and throat; carries gustatory afferents from posterior tongue and afferents from the carotid body and carotid sinus that convey information about blood pressure and blood. |
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Term
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Definition
| A map of the cortex representing the body surface. |
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Term
| Inferior mesenteric ganglia |
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Definition
| One of four major unpaired prevertebral ganglia located in the abdomen and pelvis. |
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Term
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Definition
| A single tubular axon that sprouts from the cell body at a bump. Also called an axon hillock. |
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Term
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Definition
| The cranial nerve that innervates the muscles of the tongue. |
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Term
| Inferior hypogastric ganglia |
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Definition
| One of four major unpaired prevertebral ganglia located in the abdomen and pelvis. |
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Term
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Definition
| Any change in the direction of an even more inside-negative potential. |
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Term
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Definition
| Postsynaptic potentials that tend to decrease the likelihood that the postsynaptic cell will initiate an action potential at the axon hillock. |
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Term
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Definition
| When the inactivation gate remains closed, the channel cannot be reopened by depolarization. |
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Term
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Definition
| Once the channel has entered the open state this gate can swing into place and close the channel. While the inactivation gate remains closed, the channel cannot be reopened by depolarization. |
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Term
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Definition
| One type of neurotransmitter receptor that is also an ion channel. Binding of the transmitter to the ionotropic receptor opens the channel, resulting directly in a permeability change. |
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Term
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Definition
| Regular intervals in which myelinated axons are surrounded by a multilayered sheath formed by glia. |
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Term
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Definition
| The paired, C-shaped ventricles within the cerebral hemispheres. |
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Term
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Definition
| Contains the spinothalamic pathway. |
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Term
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Definition
| A region of the brain stem. |
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Term
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Definition
| Separates the cerebrum into right and left hemispheres. |
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Term
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Definition
| Also called association neurons, these are the most numerous neurons that have their processes entirely within the CNS and are involved in processing information for an appropriate response. |
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Term
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Definition
| A hormone secreted by the pineal gland that contributes to control of the body’s sleeping-waking cycle. |
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Term
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Definition
| Nerves that contain both afferent and efferent axons. |
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Term
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Definition
| Also known as the mesencephalon, located within the brain stem. |
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Term
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Definition
| The midbrain portion of the brain stem. |
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Term
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Definition
| A receptor that is coupled to intracellular second messengers by way of G proteins and may be coupled to different second messenger systems in different cell types. |
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Term
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Definition
| The cerebellum and pons portion of brain stem. |
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Term
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Definition
| The three membranes of connective tissue that surround the whole CNS. The outermost membrane is the tough dura mater. Just deep to the dura mater is the arachnoid mater, and inside that the pia mater. |
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Term
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Definition
| The cells of the nonspecific immune system rather than true glia cells—they are the form that macrophages take in the brain. |
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Term
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Definition
| A fatty substance that insulates axons. |
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Term
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Definition
| The medulla oblongata portion of brain stem. |
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Term
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Definition
| Sites in a myelinated axon in which the sheath is interrupted at regular intervals, leaving the axonal membrane bare. |
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Term
| Monosynaptic stretch reflex |
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Definition
| The only type of human reflex that is monosynaptic, in which there are no interneurons in the reflex arc and all integration takes place at synapses of the sensory neurons on the motor neurons. A stretch reflex may be evoked by tapping on a muscle or its tendon. |
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Term
|
Definition
| Surround the dome axons of some central neurons. |
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Term
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Definition
| Originates in early development and is formed from a dorsal infolding of ectoderm, the outermost of the three embryonic cell layers. |
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Term
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Definition
| An enzyme that packages for reuse or breaks down any given molecule of recovered norepinephrine. |
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Term
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Definition
| Long axons found in peripheral nerves that have a thread-like appearance. |
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Term
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Definition
| One of three states a Na+ channel may exist in which the transmembrane potential and can be opened by depolarization. |
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Term
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Definition
| The cranial nerve that contains efferents that innervate four of the six extrinsic eye muscles and parasympathetic fibers that innervate the iris of the eye. |
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Term
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Definition
| A wrapping that separates fascicles from one another. |
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Term
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Definition
| The innermost layer of the meninges that surround the whole CNS. |
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Term
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Definition
| A class of glial cells in the CNS that is responsible for laying down the myelin sheaths that surround the axons of some central neurons. |
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Term
| Paravertebral chain ganglion |
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Definition
| Part of the sympathetic pathway to the effectors. |
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Term
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Definition
| The most caudal lobes that are the site of the primary visual area. |
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Term
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Definition
| The major structure of the epithalamus that is an unpaired, knoblike structure that secretes melatonin. |
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Term
| Polysynaptic Withdrawl reflex |
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Definition
| The reflex arc includes one or more interneurons. The withdrawal reflex is a commonly experienced polysynaptic spinal reflex that results in a generalized flexion of an appendage in response to an aversive stimulus. |
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Term
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Definition
| Interlacing networks formed by the ventral rami of all spinal nerves, with the exception of T2–T12, by joining one another lateral to the vertebral column. |
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Term
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Definition
| A resting cell’s membrane in which it is charged electrically with a positive and negative pole. |
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Term
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Definition
| An extremely important element of the endocrine system, projects inferiorly from the hypothalamus. |
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Term
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Definition
| A region in the brain stem. |
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Term
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Definition
| The primary somatosensory areas of the cortex. |
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Term
| Posterior spinocerebellar tracts |
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Definition
| Located within the spinocerebellar pathway, carrying information from muscle and joint receptors to the cerebellum. |
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Term
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Definition
| The second neuron of the autonomic pathways; In the peripheral ganglion, the neuron on which the preganglionic cell’s axon synapses and then projects to an effector in a visceral organ. |
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Term
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Definition
| In a synaptic transmission, the recipient cell. |
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Term
| Postsynaptic potential (PSP) |
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Definition
| Caused by the binding of transmitter to its receptor initiates a permeability change in the postsynaptic cell. |
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Term
| Posterior horns (Dorsal horns) |
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Definition
| Central gray matter is shaped like a capital H and the horns are the arms of the H that project posteriorly. |
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Term
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Definition
| The prosencephalon (forebrain), mesencephalon (midbrain), and rhombencephalon (hindbrain). |
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Term
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Definition
| The primary motor areas of the cortex. |
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Term
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Definition
| Located in the temporal lobe. |
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Term
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Definition
| The first neuron of the autonomic pathways; its cell body is in the CNS, and its axon projecting to a peripheral autonomic ganglion. |
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Term
| Prosencephalon (forebrain) |
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Definition
| One of three primary brain vesicles. |
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Term
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Definition
| The point in which a preganglionic axon synapses on a postganglionic neuron that projects to an effector in the abdominal cavity. |
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Term
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Definition
| Carry axons of neurons in the motor cortex that traverse the cord without synapsing until they reach neurons in the spinal segments. |
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Term
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Definition
| Lies rostral to the motor areas of the precentral gyrus, and is important for activities that involve reasoning, complex learning abilities, long-term planning, and judgment and is also involved in mood, emotions, and social behavior. |
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Term
| Rhombencephalon (hindbrain) |
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Definition
| One of the three primary brain vesicles. |
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Term
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Definition
| In the resting cell, the plasma membrane is mainly permeable to K+, and the inside-to-outside concentration gradient tends to drive K+ toward the outside of the cell, giving the membrane a slight excess of positive charge on the outside surface of the membrane and a corresponding slight excess of negative charge on the inside. |
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Term
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Definition
| The organization of neurons and effectors, which is the simplest way of organizing the nervous system to achieve an appropriate response. |
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Term
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Definition
| The medial gray ramus and the lateral white ramus that connect the base of each ventral ramus to a corresponding sympathetic chain ganglion, part of the sympathetic branch of the autonomic motor system. |
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Term
|
Definition
| A state in which closed channels could be thought of as available to be opened by depolarization. |
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Term
| Relative refractory period |
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Definition
| A period after the absolute refractory period during which a second action potential can be initiated, but the stimulus must be more intense. |
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Term
|
Definition
| The map-like organization of the brain. |
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Term
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Definition
| When an action potential occurs, the membrane potential changes rapidly from its resting inside-negative value to an inside-positive value (peaking typically in the range of +20 to +50 mV) and just as quickly returns to the resting value. |
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Term
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Definition
| In the PNS, the glial cells responsible for myelinating CNS neurons. |
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Term
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Definition
| One region of the PNS that consists of the skeletal muscles and body surface. |
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Term
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Definition
| Multiple synapses located on the same postsynaptic cell. |
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Term
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Definition
| The major nerves of the spine; there are thirty-one pairs of spinal nerves. |
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Term
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Definition
| A nerve that a preganglionic axon can follow after passing through the chain ganglion without synapsing. |
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Term
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Definition
| Located in the anterior and lateral spinothalamic tracts, the pathway carries information about coarse touch, temperature, and pain sensations to the primary somatosensory cortex. |
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Term
|
Definition
| Shallow grooves created by folding of the cortex as it grows. |
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Term
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Definition
| Carries information from muscle and joint receptors to the cerebellum. |
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Term
| Sympathetic chain ganglia |
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Definition
| A paired series lying parallel to the spinal column on each side and connected to the ventral rami of T1–L1 by rami communicantes. |
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Term
|
Definition
| The reflex arc does not include brain neurons and is typically limited to one or a few adjacent spinal segments. |
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Term
|
Definition
| The points of close contact between axon terminals and the target cells. |
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Term
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Definition
| A narrow space that separates the presynaptic cell and the postsynaptic cell. |
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Term
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Definition
| The process of sending information across synapses. |
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Term
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Definition
| Continual use of a particular pathway may result in depletion of the stores of transmitter, decreasing the efficacy of the synapses. |
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Term
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Definition
| A small, membrane-bound vesicles that stores neurotransmitter chemicals in the axon terminal. |
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Term
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Definition
| The roof of the cerebral aqueduct that runs through the midbrain. |
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Term
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Definition
| Represents the time required for the presynaptic cell to organize transmitter release, for the transmitter to diffuse to receptors, and for the activated receptors to cause a PSP. |
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Term
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Definition
| In the forebrain, the cerebral cortex and basal nuclei. |
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Term
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Definition
| Several action potentials that arrive one after the other at the same synapse. |
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Term
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Definition
| The site of the primary auditory area. |
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Term
| Thalamocortical fiber tracts |
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Definition
| Relay information from the somatosensory, visual, auditory, olfactory, and gustatory sensory systems to the primary processing areas in the cortex. |
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Term
|
Definition
| Branches formed at the end of axons, ending in axon terminals. |
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Term
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Definition
| A rapid rise in the membrane potential. |
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Term
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Definition
| Located in the center of the diencephalon. |
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Term
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Definition
| The only cranial nerve to extend beyond the head/neck; innervates larynx and contains afferents and parasympathetic efferents from/to thoracic and abdominal viscera. |
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Term
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Definition
| Separates the cerebral hemispheres from the cerebellum. |
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Term
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Definition
| A cranial nerve that contains afferents from the face and innervates masticatory (chewing) muscles. |
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Term
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Definition
| Forming the outer layer of the spinal cord; also the location of the cerebral basal nuclei. |
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Term
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Definition
|
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Term
|
Definition
| Each spinal segment has a pair that project from the anterolateral surface. |
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Term
|
Definition
| Central gray matter is shaped like a capital H and the horns are the arms of the H that project anteriorly. |
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Term
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Definition
| One region of the PNS that consists of the soft internal organs of the digestive system, lungs, heart, and blood vessels, etc. |
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Term
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Definition
| The lateral branch of the rami communicante that connects the base of each ventral ramus to a corresponding sympathetic chain ganglion. |
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Term
|
Definition
| A system of four interconnected spaces of the brain filled with cerebrospinal fluid (CSF). |
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