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82 terms

Nervous Tissue

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Neuroglia
cells that support and nourish neurons
Astrocytes
largest, most numerous glial cells; maintain blood-brain barrier to isolate CNS from general circulation; provide structural support for CNS; regulate ion and nutrient concentrations; perform repairs to stabilize tissue and prevent further injury
Astrocytes
Oligodendrocytes
wrap CNS axons in a myelin sheath
Oligodendrocytes
Ependymal cells
Type of neuroglial cell found in the ventricles, circulate cerebrospinal fluid
Ependymal cells
Microglia
Act as phagocytes, eating damaged cells and bacteria, act as the brains immune system
Microglia
Schwann cells
Supporting cells of the peripheral nervous system responsible for the formation of myelin.
Schwann cells
Satellite cells
Type of glial cell, line the exterior surface of neurons in the peripheral nervous system. Satellite cells also surround neuron cell bodies within ganglia. They supply nutrients to the surrounding neurons and also have some structural function.
Satellite Cells
soma
cell body of a neuron
soma
Nuclei
groups of nueron cell bodies in spinal cord gray matter
Nuclei
nucleolus
Neurofibrils
bundles of intermediate filaments (neurofilaments); maintain shape
Nissl Bodies
rough endoplasmic recticulum in neurons; important for protein production, i.e. NA/K protein channels
Nissl Bodies
Dendrites
branching extensions of neuron that receives messages from neighboring neurons
Dendrites
Axons
a part of a neuron that carries impulses away from the cell body
Axons
Input Zone (Dendrites, Cell Body)
The part of a neuron that receives information, from other neurons or from specialized sensory structures. Usually corresponds to the cell's dendrites.
Trigger Zone (Initial Segment of Axon)
nerve impulses arise most often at the junction of the axon hillock and initial segment
Conducting zone (Axon)
The zone where action potentials propagate along the axon
Output Zone (Axon Terminals)
swellings at the ends of the axon known as axon terminals that communicate the cell's acitivity to other cells
Collaterals
side branches from an axon
Collaterals
Axon Hillock
specialized region of the axon, which connects the inital segment of the axon to the cell body
Axon Hillock
Axon Terminals
bulb like structers at end of axon contain neuro transmitters that carry neuron message into synapse
Axon Terminals
Synaptic End Bulbs
found at end of axon terminal & contain synaptic vesicles that are filled with neurotransmitters
Synaptic End Bulbs
Neurotransmitters
chemical messengers that traverse the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.
Neurotransmitters
Synaptic Vesicles
tiny oval-shaped sacs in a terminal of one neuron; assist in transferring mineral impulse from one neuron to another neuron by releasing specific neurotransmitters
Synaptic Vesicles
Synaptic Cleft
synaptic gap or synaptic space; tiny gap between the terminal of one neuron and the dendrites of another neuron (almost never touch); location of the transfer of an impulse from one neuron to the next
Synaptic Cleft
Membrane Receptors
cell communicaton via chemical signals-receptors specificity/ receptor activation produces a second messengr(chemical) inside of cell
Action Potential
a neural impulse; a brief electrical charge that travels down an axon. the action potential is generated by the movement of positively charged atoms in and out of channels in the axon's membrane
Myelin
a fatty substance that helps insulate neurons and speeds the transmission of nerve impulses
Myelin
Neurilemma
thin membranous sheath around a nerve fiber
Neurilemma
Nodes of Ranvier
small gaps of exposed axon, between the segments of myelin sheath, where action potentials are transmitted
Nodes of Ranvier
Axolemma
The plasma membrane of the axon
Axoplasm
cytoplasm of the axon, contains numerous organelles
Unipolar Neuron
neuron with just one process extending from the cell body; are always sensory nerons
Unipolar Neuron
Bipolar Neuron
A neuron with a single axon and a single dendrite, often projecting from opposite sides of the cell body. Bipolar neurons are typically associated with sensory organs; an example is the bipolar neuron in the retina of the eye. - note that one axon may innervate many different muscles, or other things.
Bipolar Neuron
Multipolar Neuron
A nerve cell that has many dendrites and a single axon.
Multipolar Neuron
Sensory Neurons (Afferent)
neurons that carry incoming information from the sensory receptors to the brain and spinal cord
Motor Neurons (efferent)
neurons that carry outgoing information from the central nervous system to the muscles and glands
Association Neurons (Interneurons)
Also called interneurons, located only in the brain or spinal cord, these neurons contact sensory neurons to motor neurons; the switch board of the nervous system.
Endoneurium
delicate connective tissue around individual nerve fibers in nerve
Endoneurium
Perineurium
connective tissue that covers a bundle of nerve fibers
Perineurium
Fascicle
a bundle of fibers (especially nerve fibers)
Epineurium
outermost layer of connective tissue on the spinal nerve; a dense network of collagen fibers
Epineurium
Dorsal Root
contains the axons of the sensory neurons in the dorsal root ganglion; each segment of the spinal cord is associated with a pair of these
Dorsal Root
Ventral Root
contains axons of somatic motor neurons and sometimes visceral motor neurons that control peripheral effectors; each segment of the spinal cord is associated with a pair of these
Ventral Root
MIxed Nerves
nerves composed of both sensory and motor fibers, nerves that contain both sensory and motor fibers and have the ability to send and receive messages
MIxed Nerves
Gray Matter
Brain and spinal cord tissue that appears gray with the naked eye; consists mainly of neuronal cell bodies (nuclei) and lacks myelinated axons.
White Matter
whitish nervous tissue of the CNS consisting of neurons and their myelin sheaths
Plexus
large, interlacing network of nerves
Nuclei
clusters of cell bodies in the CNS
Ganglia
groups of nerve cell bodies that coordinate incoming and outgoing nerve signals
Nerve
any bundle of nerve fibers running to various organs and tissues of the body
Tract
a bundle of mylenated nerve fibers following a path through the brain