Nervous System Flashcards
Neuron
Nerve cell
Impulse
An action potential
Synapse
Functional connection between the axon terminal of a neuron and the dendrite or cell body of another neuron or the membrane of another cell type
Neurotransmitters
Chemical that an axon secretes at a synapse that stimulates or inhibits an effector (muscle or gland) or other neuron
Cell body
Part of a neuron that includes cytoplasm and a nucleus, and form which nerve processes extend
Dendrite
Process of a neuron that receive input from other neurons
Axon
The process that conducts an impulse away from the neuron cell body. A nerve fiber
Central nervous system
(CNS) The brain and spinal cord
Peripheral nervous system
(PNS) Parts of the nervous system outside the brain and spinal cord
Neuroglia
Specialized cells of the nervous system that, depending on the type of neuroglia, produce myelin, maintain the ionic environment, provide growth factors that support neurons, provide structural support, and play a role in cell to cell communication
Sensory Receptor
Specialized structure associated with the peripheral end of a sensory neuron specific to detecting a particular stimulus and triggering an impulse in response.
Effectors
A muscle or gland, either of which can effect change in the body
Somatic nervous system
Motor pathways of the peripheral nervous system that lead to skeletal muscles
Autonomic nervous system
Motor portion of the peripheral nervous system that control the viscera and operates without conscious effort
Myelin
Lipid material that forms a sheath-like covering around some axons. It provides electrical insulation
Myelin sheath
lipid-rich layer formed from certain neuroglia that wraps around an axon, providing insulation.
Neurofilaments
fine, cytoplasmic threads that extend from the cell body into the axon for its entire length
Chromatophilic substance
(Nissl bodies) Membranous sacs in the cytoplasm of neurons that have ribosomes attached to their surfaces
Neurilemma
outer layer formed from Schwann cells on the the exterior of some axons, outside of the myelin sheath
Nodes of ranvier
the many gaps in the myelin sheath along axons of myelinated neurons of the peripheral nervous system
Ganglion
(plural, ganglia) Mass of neuron cell bodies outside the central nervous system
Sensory neuron
neuron that conducts impulses from sensory receptors to the central nervous system
Interneuron
neuron within the CNS, often connecting a sensory neuron and a motor neuron; internuncial or association neuron
Nucleus
(plural, nuclei) (1) the dense core of an atom, composed of protons and usually neutrons. (2) cellular organelle enclosed by double-layered, porous membrane and containing DNA. (3) masses of interneuron cell bodies in the central nervous system.
Motor neuron
neuron that conducts impulses from the central nervous system to an effector
