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38 Cards in this Set
- Front
- Back
Cells of the Nervous System |
1. Neurons (send and receive messages) 2. Glia (support cells of the nervous system) |
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Neurons |
work in unison to produce functions
structure is constantly changing (essence of plasticity)
have tremendous longevity (most last a lifetime, never being replaced) |
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Atoms are |
the smallest quantity of an element |
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Atomic nucleus contains |
neutrons (neutral in charge)
protons (positive in charge) |
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Electrons orbit |
the nucleus
carry a negative charge |
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an atom with a charge either positive or negative is an |
ion |
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molecules form when |
atoms bind together |
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Neuron Structure like other cells |
cell body
membrane
cytoskeleton
organelles |
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neuron structure unique to neurons |
dendrites
axons
axon terminals |
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cell body |
similar organelles (internal parts of the cell) and similar functions as other cell types
location of some neuronal input (receives messages) |
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Organelles |
nucleus (contains chromosomes and genes)
endoplasmic reticulum [ER] (folded layers of membrane where proteins are assembled
golgi apparatus ( packages proteins for transport)
mitochondria (gathers, stores and releases energy
lysosomes (contains enzymes that break down waste |
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the cell membrane |
separates the cell's intracellular space from extracellular fluid
double layered structure
phosphate heads (hydrophilic)
lipid [fatty] tails (hydrophobic)
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semi-permeable cell membrane |
regulates movement in and out of cell
proteins embedded within the membrane |
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cell membrane movement is regulated by |
diffusion (passive): no doors
ion channels (passive): open doors
gated ion channels (passive): locked doors
pumps (active): revolving doors |
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ion channels |
passive
open doors
different sizes allow different ions in |
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gated ion channels |
passive
locked doors
voltage or chemical (ligand) dependent |
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ion pumps |
active
revolving doors
require a lot of energy |
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the cytoskeleton is comprised of 3 components |
microtubules
neurofilaments
microfilaments |
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microtubules |
highway system
anterograde (cell body to axon terminal)
retrograde (axon terminal to cell body) |
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neurofilaments |
skeletal system |
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microfilaments |
scaffolding
helps dendrites and axons change their shape and size |
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neuron |
information travels from head to toe |
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dendrites |
input zone
receives info from other neurons
hair of stick figure |
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dendritic spines |
bumps on the dendrites |
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post-synaptic sites |
receiving end of the synapse
contains receptors (specialized proteins in the membrane that bind neurotransmitter) |
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the axon |
one axon per neuron
can vary in speed of transmission (the thicker the faster; insulating axons [myelin]=faster transmission)
can vary in length (short local axons; long projection axons)
divided into many branches to allow for communication with many cells (can have multiple feet to our stick figure) |
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Axon hillock |
integration zone
tapered segment of axon between the cell body and axon (neck of stick figure)
messages start at the axon hillock |
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the axon conduction zone |
myelin = axon insulation (allows for faster more efficient signaling)
nodes of ranvier = unmyelinated segments of the axon |
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the axon terminal |
output zone
pre-synaptic portion of the synapse (sending end of the synapse)
filled with neurotransmitter |
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morphological variations of neurons |
multipolar neurons = one axon, many dendrites
bipolar neurons = one axon, one dendrite
unipolar neurons = a single branch in 2 directions (one input zone, one output zone) |
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flow of information of neuron |
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functional variations in neurons |
sensory neurons: receive inputs via sense organs and sense receptors
motor neurons: send outputs via muscles and glands
interneurons: bridge between sensory and motor neurons allowing for modulations (changes, refinements) |
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Glia |
support cells of the nervous system
10-50 glia per neuron
Big= macroglia
Small= microglia |
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3 types of macroglia |
astrocytes
oligodendrocytes
schwann cells |
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astrocytes |
star shaped
multiple functions (structural support, nutritional support, blood-brain barrier[keeps things in the blood out of the brain], surround the synapse, clean-up)
can be harmful in injury (glia scar) |
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oligodendrocytes |
make myelin in the central nervous system (CNS = brain and spinal chord)
functions include (myelinate many axons = 15 on average, structural support)
not involved in regrowth following injury |
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schwann cells |
makes myelin in the peripheral nervous system [PNS includes everywhere but the brain and spinal chord]
functions include (myelinate 1 axon segment (many schwann cells needed to myelinate 1 axon))
is involved in regrowth after injury |
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microglia |
immune cells of the brain
clean-up
can be pro-survival or pro-inflammatory (2 faces of microglia) |