Nervous System Flashcards
neuron
specialized nervous tissue with the purpose of transmitting electrical signals
central nervous sytem
brain which is housed in the cranium and the spine which is housed in the vertebral column
peripheral nervous system
nerves that connect to the rest of the body
nerves
an organ composed of bundles of axons, connective tissue layers, and blood vessels
somatic sensory
consciously perceive stimuli
visceral sensory
detects stimuli that we don’t usually consciously perceive
epineurium
outermost supporting connective tissue layer of peripheral nerves
perineurium
fibrous sheath enveloping each of the fascicles within nerves
endoneurium
areolar connective tissue that surrounds each axon of a peripheral nerve
cranial nerves
extend from the brain itself
spinal nerves
extend from the spine
sensory nerves
takes information to the CNS
motor nerves
receives information from the CNS
ganglion
cluster of neuron cell bodies within the PNS
nervous tissue
primary tissue of the nervous system, consists of either neurons or glial cells
soma
neuron cell body
perikaryon
cytoplasm within the neuron cell body
dendrites
small tapering processes that branch off the cell body
axoplasm
cytoplasm in the axon
axolemma
plasma membrane of an axon
axon
longer process emanating from the cell body, meant to make contact with other neurons
synapse
specific location where a neuron is functionally connected to either another neuron or effector (muscle or gland)
glial
cells that are sometimes referred to as neuroglia. they’re smaller then neurons and capable of cell division. they don’t transmit electrical signals but instead assist neurons
astrocyte cells
star like shape and most abundant in the CNS
ependymal cells
simple cuboidal cells that lines the internal caves of the brain and central canal of the spinal cord
microglial cell
small cells with branches extending from the main body. smallest percentage of CNS cells
satellite cells
flattened cells around neuronal cell bodies and ganglion
schwan cells
elongated ang flattened cells that wrap around PNS cells to form a myelin sheath
oligodendrocyte
large cells with bulbous bodies and slender cytoplasmic extensions which wraps around axons for insulation
unipolar neurons
single shot neuron processes that branch out like a T
bipolar neurons
2 processes that extend from either side of the body, one axon and one dendrite, extremely limited in the body
multipolar neurons
many dendrites and a single axon which makes them the most common neuron type
pumps
maintains specific concentration gradients by moving substances against a concentration gradient
channels
provides the means for a substance to move down with its concentration gradient. Contains 2 types of channels: Leak (passive) channels, and Chemically Gated Channels.
leak channels
always open and allows for constant diffusion of a specific gradient (high concentration to low concentration)
Chemically Gated Channels
normally closed but temporarily open in response to binding of a neurotransmitter and only allows for a specific type of ion to diffuse
Voltage Gated Channels
normally closed but sometimes change in response to changes in electrical potential in the plasma membrane
Generation of an EPSP
neurotransmitter is released, chemically gated cation channels open, EPSP is established, EPSP moves towards initial segment.
all or none law
if a threshold is reached there will be no changed in intensity. works opposite way too
neurotransmitters
small organic molecules that are synthesized by neurons and stored within vesicles within synaptic knobs
neuromodulators
substances that locally regulate or alter the response of neurons to neurotransmitters
facilitation
when there is greater response from a postsynaptic neuron because of the release of neuromodulators
inhibition
when there is less response from a postsynaptic neuron because of the release of neuromodulators
