Chapter 12 Nervous Tissue Flashcards
General term for any process (ason or dentrite) projecting from the cell of a neuron.
Nerve Fiber
A neuronal process that carries electriacal signals, usually graded potentials, toward the cell body.
Dendrite
Multilayered lipid and protein covering, formed by Schwann cells and oligodendrocytes, around axos of many peripheral and central nervous system neurons.
Myelin Sheath
One of the 31 pairs of nerves that originate on the spinal cord from posterior and anterior roots.
Spinal nerve
A hormone secreted by the adrenal medulla that produces actions similar to those result from sympathetic stimulation. Also called noradrenaline
Norepinephrine
The breakdown of Nissl bodies into finely granular masses in the cell body of a neuron whose axon has been damaged
Chromatolysis
one of the two subdivisions of the atonomic nervous system, having cell bodies of preganglionic neurons in nuclei in the brain stem and in the lateral gray horn of the sacral portion of the spinal cord; primarily concerned with activities that conserve and restore body energy.
Parasympathetic division
Espanded distal end of an axon terminal that contains synaptic vesicles. Also called a synaptic knob.
Synaptic end bulb
A mass of nerve tissue located in the vertebral canal from which 31 pairs of spinal nerve originate.
Spinal cord
A sunaptic arrangment in which the synaptic end bulbs of one presynaptic neuron terminate on several postsynaptic neurons.
Divergence
One of a variety of molecules within axon terminals that are released into the synaptic cleft in response to a nerve impulse and that change the membrand potential of the postsynaptic neuron
Neurotransmitter
Usually a group of nueronal cell bodies lying outside the central nervous system. Plural is ganglia
Gaglion
The part of the central nervous system contained within the cranial cavity
Brain
The peripheral, nucleated cytoplasmic layer of Schwann cell. Also called sheath of Schwann.
Neurolemma
Neurons that carry sensory information from cranial and spinal nerves into the brain and spinal cor or form a lower to higher level in the spinal cord and brain. Also called sfferent neurons.
Sensory neurons
Degeneration of the portion of the aoxon ad myelin sheath of a neuron distal to the site of injury
Wallerian degeneration
Flat neuroglial cells that surround cell bodies of peripheral nervous system ganglia to provide structural support and regulate the exchange of material between a neronal cell body and interstitial fluid.
Satellite cell
Neurons whoes axons extend only for a short distance and contact nerby nearby neurons in the brain, spinal cord, or a ganglion; they comprise the vast majority of neurons in the body
Interneurons
Aggregations or bundles of myelinated and unmyelinated axons located in the brain and spinal cord.
White matter
the part of the nervous system that is embedded in the submuccosa and muscularis of the gastrointestinal tract; governs motility and secretions of the GI tract.
Enteric nervous system
an organ of the body, either a muscle or a gland that is innervated by somatic or autonomic molor neurons.
Effector
Movement in which a part of the body moves inferiorly
Depression
A neuroglial cell of the peripheral nervous system that forms the myelin sheath and neurolemma around a nerve axon by wrappying around the axon in a jelly-roll fashion.
Schwann cell
Aneurotransmitter liberated by many peripheral nervous system neurons and some central nervous system neurons. It is excitatory at neuromuscular junctions but inhibitory at some other synapses (for example, it slows heart rate)
Acetylcholine
Any stres tht changes a controlled condition; any change in the internal or external environment tha excites a sensory receptor, a neuron, or a muscle fiber.
Stimulus
A bundle of nerve axons in the central nervous system.
Tract
Visceral sensory (afferent) and visceral motor (efferent) neurons. Autonomic motor neurons, both sympathetic and parasympathetic, conduct nerve impulses from the centeral nervous system to smooth muscle, cardiac muscle, and glands. So named because this part of the nervous system was throught to be self-governing or spontaneous.
Autonomic nervous system
That portion of the nervous system that consists of the brain and spinal cord
Central nervous system
An electrical signal that propagates alond the membrane of a neuron or muscle fiber (cell); a radpid change in the membrane potential that invovles a depolarization followed by a repolarization. Also called a nerve action potential or nerve impusles as it ralates to a neuron, and a muscle action potential as it rlates to muscle fiber.
Action potential
Membrane-enclosed sac in a synaptic end bulb that stores neurotransmitters.
Synaptic vesicle
Neurons that conduct impulses from the brain toward the spinal cord or out of the brain and spinal cord into cranial or spinal nerves to effectors that may be either muscles or glands. Also called efferent neurons.
Motor neurons
Muscle fiber (cel) in the ventricular tissue of the heart specialized for conductiong an action potential to the myocardium; part of the conduction system of the heart.
Purkinje fiber
Neuroglial cells that cover choroid plexuses and produce cerebrospinal fluid (CSF); they also line the ventricles of the brain and probably assist in the circulation of CSF
Ependymal cells
the functional junction between two neurons or between a neuron and an effetor, such as muscle or gland; may be electrical or chemical
Sunapse
a neuroglial cell having a star shape that participates in brain development and the metabolism of neurotrasmitters, helps form the blood-brain barrier, helps maintain the proper balance of K+ for generation of nerve impulses, and provides a link between neurons and blood vessels.
Astrocyte
A neuron that propagats nerve impulses toward a synapse
Presynaptic neuron
The muscle directly responsible for producing a desired motion. Also called an agonist.
Prime mover
A cordlike bundle of neuronal axons and/or dendrites and associated connective tissue coursing together outside the central nervous system.
Nerve
The part of the nervous system that lies outside the central nervous system consisting of nerves and ganglia.
Peripheral nervous system
A neuroglial cell that supports neurons and produces a myelin sheath around axons of neurons of the central nervous system.
Oligodendrocyte
Cells of the nervous system that perform various supportive functions. The neuroglia of the central nervous systems are astrocytes, olgodencrocytes, microglia, and ependymal cells; neuroglia of the peripheral nervous system include Schwann cells and statellite cells. Also called glial cells.
Neuroglia
A spherical or oval organelle of a cell that contains the hereditary factors of the cell, called genes. A cluster of unmyelinated nerve cell bodies in the central nervous system. The central part of an atom made up of protons and neutrons.
Nucleus
The study of the normal functioning and disorders of the nervous system.
Neurology
One of the two subdivisions of the autonomic nervous system, having cell bodies of preganglionic neurons in the lateral gray columns of the thoracic segment and the first two or three lumbar segments of the spinal cord; primarily concerned with processes invovlgin the expenditure of enery.
Sympathetic division
The portion of the peripheral nervous system consisting of somatic sensory 9afferent) neurons and somatic motor (efferent) neurons
Somatic nervous system
The usually single, long process of a nerve cell that propagates a nerve impulse toward the axon terminals.
Axon
The surface of the cerebral hemispheres, 2-4mm thick, consisting of gray matter; arranged in six layers of neuronal cell bodies in most areas.
Cerebral cortex
The nerve cell that is activated by the release of a neurotransmitter from another neuron and carries nerve impulses away from the synapse.
Postsynaptic neuron
terminal branch of an axon where synaptic vesicles undergo exocytosis to release neurotransmitter molecules
Axon terminal
a muscle that has an action opposite that of the prime mover (agonist) and yields to the movement of the prime mover
Antagonist
Hormone secreted by the adrenal medulla that produces actions similar to those that result from sympathetic stimulation. Also called adrenaline.
Epinephrine
A nerve cell, consisting of a cell body, dendrites and an axon
Neuron
a neuron that secretes a hypothalamic releasing hormone or inhibiting hormone into blood capillaries of the hypothalums; a neuron that secretes oxytocin or antidiuretic hormone into blood capillaries of the posterior pituitary.
Neurosecretory cell
A synaptic arrangemtn in which the synaptic end bulbs of several presynaptic neurons terminate on one postsynaptic neuron. The medial movement of the two eyeballs so that both are directed towad a near object being viewed in order to produce a single image.
Convergence
propagation of an action potential (nerve impulse) in a step by step depolarization of each adjacent area of an axon membrane
continuous condution
A space along a myelinated axon between the individual Schwann cells that form the myelin sheath and the neurolemma. Also called neurofibral node.
Node of Ranvier
Areas in the central nervous system and ganglia containing neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglia; Nissl bodies impart a gray color and there is little or no myelin in gray matter.
Gray matter
The narrow gap at a chemical synapse that separates the axon terminal of one neuron from another neuron or muscle fiber (cell) and across which a neurotransmitter diffuses to affect the postsynaptic cell
Synaptic cleft
