Chapter 2 Flashcards
Neuron (nerve cell)
The basic unit of the nervous system, each composed of a cell body, receptive extension(s) (dendrites), and a transmitting extension (axon)
Glial Cells (glia/neuroglia)
Nonneuronal brain cells that provide structural, nutritional, and other types of support to the brain
Neuron Doctrine
The hypothesis that the brain is composed of separate cells that are distinct structurally, metabolically, and functionally
Synapse
The tiny gap between neurons where information is passed from one to the other
Mitochondrion
A cellular organelle that provides metabolic energy for the cell’s processes
Cell Nucleus
The spherical central structure of a cell that contains the chromosomes
Ribosomes
Structures in the cell body where genetic information is translated to produce proteins
Dendrite
One of the extensions of the cell body that are receptive surfaces of the neuron
Input Zone
The part of the neuron that receives information, from other neurons or from specialized sensory structures. Usually corresponds to cells’ dendrites
Cell Body/Soma
The region of a neuron that is identified by the presence of a cell nucleus
Integration Zone
The part of the neuron that initiates nerve electrical activity. Usually corresponds to the neuron’s axon hillock.
Axon
A single extension from the nerve cell that carries nerve impulses from the cello body to other neurons
Conduction Zone
The part of the neuron over which the nerve’s electrical signal may be actively propagated. Usually corresponds to the cell’s axon.
Axon Terminal (Synaptic Bouton)
The end of an axon or axon collateral, which forms a synapse on a neuron or other target cell
Output Zone
The part of the neuron, usually corresponding to the axon terminals, at which the cell sends information to a another cell
Multipolar Neuron
A nerve that has many dendrites and a single axon. (most common type of neuron)
Bipolar Neuron
A nerve cell that has a single dendrite at one end and a single axon at the other. (common in sensory systems)
Unipolar Neuron (Monopolar Neuron)
A nerve cell with a single branch that leaves the cell body and then extends in two directions; one end is the receptive pole, the other end is the output zone. (transmit touch information from the body to the spinal cord)
Motoneuron (Motor Neuron)
A nerve cell that transmits motor messages, stimulating a muscle or gland. Have long axons reaching out to synapse on muscles.
Sensory Neuron
A neuron that is directly affected by changes in the environment, such as light, odor, or touch.
Interneuron
A neuron that is neither sensory nor motor; it receives input from and sends output to other neurons.
Arborization
The elaborate branching of the dendrites of some neurons
Presynaptic
Region of the synapse that releases the neurotransmitter
Postsynaptic
Region of the synapse that receives and responds to neurotransmitters.
Presynaptic Membrane
The specialized membrane of the axon terminal of the neuron that transmits information by releasing neurotransmitter
Postsynaptic Membrane
The specialized membrane on the surface of the cell that receives information by responding to a neurotransmitter from a presynaptic neuron.
Synaptic Cleft
The space between the presynaptic and postsynaptic elements
Synaptic Vesicle
A small, spherical structure that contains molecules of neurotransmitter.
Neurotransmitter (synaptic/chemical transmitter)
The chemical released from the presynaptic axon terminal that serves as the basis of communication between neurons.
Receptor (Receptor Molecule)
A protein that binds and reacts to molecules of a neurotransmitter or hormone.
Neural Plasticity
The ability of the nervous system to change in response to experience or the environment.
Axon Hillock
A cone-shaped area from which the axon originates out of the cell body. Functionally, the integration zone of the neuron.
Axon Collateral
A branch of an axon from a single neuron,
Innervate
To provide neural input,
Axonal Transport
The transportation of materials from the neuronal cell body to distant regions in the dendrites and axons, and from the axon terminals back to the cell body.
Astrocyte
A star-shaped glial cell with numerous processes (extensions) that run in all directions.
Microglial cells (microglia)
Extremely small glial cells that remove cellular debris from injured or dead cells.
Oligodendrocyte
A type of glial cell that forms myelin in the central nervous system.
Schwann Cell
The glial cell that forms myelin in the peripheral nervous system.
Myelination
The process of myelin formation.
Myelin
The fatty insulation around an axon, formed by glial cells, that improves the speed of conduction of nerve impulses.
Node of Ranvier
A gap between successive segments of the myelin sheath where the axon membrane is exposed.
Edema
The swelling of tissue, especially in the brain, in response to injury.
Multiple Sclerosis
Literally, “many scars”; a disorder characterized by widespread degeneration of myelin.
