neurology Flashcards
nervous system
the master controlling and communicating system of the body
central nervous system (CNS)
made of brain and spinal cord; commands
peripheral nervous system (PNS)
made of spinal and cranial nerves; carries messages
sensory division
part of PNS; afferent
motor division
part of PNS ; efferent
motor division 2 parts
somatic and autonomic nervous system
somotic nervous system (SNS)
skeletal muscles
autonomic nervous system (ANS)
regulates smooth muscles, cardiac, and glands
sympathetic
fight or flight
parasympathetic
rest and digest
neurons
excitable cells that transmit electrical signals
astrocyctes
most abundant glial cell; cling to neurons and cover capillaries; form blood brain barrier
microglia
small, ovoid cells with spiny processes
ependymal cells
secrete CSF (cerebrospinal fluid)
oligodendrocytes
branched cells that wrap CNS nerve fibers with myelin
schwann cells (neurolemmocytes)
surround fibers of the PNS
structural units of the nervous system
body, axon, and dendrites
perikaryon or SOMA
contains nucleus and nucleolus; has nissl bodies
axon hillock
bump in axon
tracts
in CNS
nerves
in PNS
nuclei is SOMA in
CNS
ganglia is SOMA in
PNS
dendrites
receptive/ input regions of the neuron
electrical signals are conveyed as
graded local potentials
long axons are called
nerve fibers
one unbranched axon
per neuron
rare branches are called
axon collaterals
axon function
generate and transmit action potentials
anterograde
toward axonal terminal
retrograde
away from axonal terminal
myelin sheath
increase the speed of nerve impulse transmission
myelin sheath formation
formed by schwann cells
neurilemma
remaining nucleus and cytoplasm of schwann cell
nodes of ranvier
gaps in the myelin sheath between adjacent schwann cells
no neurliemma means what functionally
no regeneration
white matter
myelinated fiber
gray matter
unmyelinated fiber
multipolar
3 or more processes
bipolar
2 processes
unipolar
single, short process
sensory transmits impulses
toward CNS
motor transmits impulses
away from CNS
interneurons shuttle signals
the CNS pathways
passive or leakage channels
always open
chemically/ ligand gated channels
open with binding of neurotransmitter
voltage gated channels
open and close in response to membrane potential
resting state of neuron
-70
graded potential
short local changes in membrane potential
action poential
a brief reversal membrane potential with an amplitude of 100
depolarization
the inside of the membrane becomes less negative
repolarization
the membrane returns back to its resting state
hyperpolarization
the inside of the membrane becomes more negative then the resting state
threshold
membrane is depolarized by 15 to 20 mV
weak stimuli
is not dependent on action potentials
strong stimuli
do relay on action potentials
the absolute refactory period
prevents the neuron from generating and action potential
axon diameter
the larger the diameter the faster the impulse
presynaptic neuron
conducts impulses toward the synapse
postsynaptic neuron
transmits impulses away from the synapse
axodendritic
synapses between the axon of the one neuron and the dendrite of another
axosomatic
synapses between the axon of the one neuron and the soma of another
neurotransmitter must
be released, diffuse across the synapse, and bind to receptors
EPSP
excitatory postsynaptic potential
IPSP
inhibitory postsynaptic potential
neurotransmitter
chemicals used for neuronal communication with the body and the brain
chemical neurotransmitters
acetylocholine, biogenic amines
catecholamines
dopamine, norepinephrine, and epinephrine
excitatory neurotransmitters cause
depolarizations
inhibitory neurotransmitters cause
hyperpolarizations
central sulcus
separates the frontal and parietal lobes
parieto occipital sulcus
seperates the parietal and occipital lobes
lateral sulcus
seperates the parietal and temporal lobes
the precentral and postcentral gyri
border the central sulcus
motor areas
control voluntary movement
sensory areas
conscious awareness of sensation
association
integrate diverse information
which lobe is the precentral gyrus located
frontal
premotor cortex
controls learned, repetitious, or patterned motor skills
which lobe is the postcentral gyrus in
parietal
wernickes area
sounding out unfamiliar words
broccas area
speech preparation and production
cerebral dominance
designates the hemisphere dominant for language
left hemisphere
controls lauguage, math, and logic
right hemisphere
controls visual spatial skills, emotion, and artistic skills
pineal glands
extends from the postierior border and secretes melatonin
brain stem has 3 regions
midbrain, pons, medulla oblongata
cerebral peduncles
2 bulging structures that contain desening pyramidal motor tracts
cerebral aqueduct
hollow tube that connects the third and fourth ventricles
superior colliculi
visual reflex centers
inferior colliculi
auditory reflex centers
amygdala
deals with anger,danger,and fear
cingulaye gyrus
expressing emotions
hippocampal structures
convert new information into long term memories
RAS
recticular activating system
what type of fibers compose the corona radiata
projection fibers
where are the perikaryons of the first order neurons located
dorsal root ganglion
where are the perikaryons of the third order neurons located
thalmus