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52 Cards in this Set
- Front
- Back
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multipolar
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common type of neuron in the central nervous system
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what does the multipolar neuron consist of
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1. cell body (soma)
2. several short, branched dendrites 3. a long, single axon |
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neuroglia
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make up half the volume of a nervous system
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4 types of neuroglia in CNS
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1. ependymal
2. astrocytes 3. oligodendrocytes 4. microglia |
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ependymal cells
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lines the central canal of the spinal cord and ventricles of the brain; secrete cerebrospinal fluid with cilias; highly branched and contact neuroglia directly
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astrocytes functions
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- isolates the CNS
- creates the 3D framework for the CNS - repairs damage tissue - guiding neuron development - controls the interstitial environment |
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oligodendrocytes
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- forms myelin sheaths (increase action potiential)
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internodes
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myelined segments
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nodes
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gaps between internodes, where axons may branch
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white matter
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because myelin is white; myelinated nerves
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grey matter
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unmyelinated nerves
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microglia
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fine branched; migrate through neural tissue; clean cellular debris (waste products and pathogens)
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ganglia
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clustered cell bodies in PNS; surronded by neuroglia for protection
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2 types of neuroglia in PNS
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1. satellite
2. Schwann cells |
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satellite cells
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(amphicytes) surrond ganglia and regulate environment around the neuron
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Schwann cells
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(neurilemmacytes) form a myelin sheathe called the neurilemma around the peripheral axons
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neurilemma
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a mylen sheath around the peripheral axons; formed by Schwann cells
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transmembrane potential
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potential at which is no net movement of a particular ion across the cell membrane is the equilibrium potential for that ion
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4 types of ions
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Na, K, Cl, Ca
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2 types of electrical signals
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graded/action potential
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graded potential
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variable strength (dependent or initiating events), loose strength as they travel through the cell; created when any stimulus that opens a gated channel
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action potential
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large uniform depolarization, travel long distances without loosing strength
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cell body includes
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nucleus
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cell body's cytoplasm is called
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perikaryon
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cell body's cytoplasm contain
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mitochondria, RER, and ribosomes
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cell body's cytoplasm's content's functions
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mitochondria - makes energy
RER - (Nissl bodies) appears gray (gray matter) ribosomes - produce neurotransmitter |
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cell body's cytoskeleton
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neurofilaments/tubules, bundles are called neurofibrils
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dendrites
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branched, recieves information from other neurons, make up 80-90% of neuron's surface area
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axon
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carries the electrical signal (action potential) to its target
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axon's cytoplasm
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axoplasm - contains neurotubules/fibrils, enzymes, and various organelles
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axon's membrane
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axolemma - specialized cell membrane
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axon's attachment to the cell body
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axon hillock
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axon's branches
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collaterals
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axon's ends
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telodendra that extends to the synaptic terminal
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synapse
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where neurons comunicate with other cells
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neurons that send messages
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presynaptic cell
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neurons that recieves messages
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postsynaptic cell
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seperation between the pre and postsynatic cell
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synaptic cleft
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expanded area of an axon
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synaptic knob
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chemical messengers
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neurotransmitter
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transport between cell body and axon
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axoplasmic transport
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how does the transport between the cell body and the axon work?
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neurotubules within the axon transport from the synaptic knob and to the cell body (powered by midochondria and kinesins)
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can the postsynaptic cell be a neuron also?
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yes
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the gap between neurons
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neuromuscular junction
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the gap between neurons and glands
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neuroglandular junction
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3 classification of neurons based on function
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1. sensory receptors
2. motor neurons 3. interneurons |
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catagories of sensory receptors
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a. interoceptors
b. exteroceptors c. proprioceptors |
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motor neurons
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efferent neurons that carry instructions from the CNS to peripheral effectors of tissues and orgnas via axons called efferent fibers
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two major efferent system
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- somatic motor neuron (SNS)
- visceral motor neurons (ANS) |
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interneurons
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association neurons
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locations of interneurons
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in the brain, spinal, and autonomic ganglia, b/w sensory and motor neurons
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functions of interneurons
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- distribution of sensory and coordination
- helps in memory, planning, and learning |
