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158 Cards in this Set

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WHEN DOES action potential OCCUR
occurs when a neuron sends information down an axon, away from the cell body.
WHAT IS action potential
is an explosion of electrical activity that is created by a depolarizing current.
WHAT IS RESTING POTENTIAL
WHEN NEURONAL MEMBRANE ISN'T SENDING A SIGNAL
WHAT STARTS ACTION POTENTIAL
WHEN A THRESHOLD STIMULUS IS RECEIVED
WHAT IF NEURON DOES NOT REACH THRESHOLD
the neuron does not reach this critical threshold level, then no action potential will fire.
what happens when a stimulus is first received
A stimulus first causes sodium channels to open
Na+
what does influx of Na+ cause
influx of Na+ causes depolaization ((sodium has a positive charge, so the neuron becomes more positive and becomes depolarized.))
what does depolarization of Na+ cause
potassium K+ channels open When they do open, potassium rushes out of the cell, reversing the depolarization.
K+ Na+
when K+ opens na+ closes
What happens when K+ channels close
depolarazation begins again in an adjacent section og membrane
where is action potential occuring
down the axon
what restores ion distribution
Na+/K+ pump
what is refractory period
after action potential the neuron has to recover to reset

resting period
how does action pontential move
moves in one direction
how do neurons send messages
Neurons send messages electrochemically. This means that chemicals cause an electrical signal. Chemicals in the body are "electrically-charged" -- when they have an electrical charge, they are called "ions.
what are neurotransmitters
Chemicals, called neurotransmitters, are released from one neuron at the presynaptic nerve terminal.
what is the chemical at the neuromuscular junction
acetytcholine
what are chemicals at synapse between neurons
epineprine (adrenaline) and norepineprine (non adrenaline)
depolarization
(an excitatory postsynaptic potential) or
hyperpolarization
(an inhibitory postsynaptic potential
does action potential occur during depolarization or hyperpolarization
depolarization
Inactivation of Neurotransmitters
1. degraded by enzymes in synapse
2. defuses out of synapse and degrades else where

3. pumped back in axon terminal
what is synapse
synapse is a small gap separating neurons
What are targets of neurons
other neurons
muscles
glands
What are sensory receptors
specialized cells in special sense organs

have modified nerve endings
what do sensory receptors react to
pressure, temperature,
pain
cutaneous and deep
where do sensory receptors stretch
muscles and tendons
another name for action potential
nerve impulse
at rest ( unstimulated) what is the neural membranes charge
neurons have build up of positive charge outside
neuronal membrane is polarized. what does this mean
has a positive side and negitive side
What chemicals cause polarization
K+ potassium
Na+ sodium
How is a neuronal membrane polarizes
greater concentration of Na+ outside and K+ inside
outside is positive compared to inside
What is depolarization
loss of polarity caused by influx of Na+
how does sodium get into the cells
*neuronal cell membranes contain channels
*channels are closed until stimulus opens them
*stimulus can be neurotransmitter for another neuron
*Na+ defusses thru chsannel
thresholds
all or nothing..either stimulus reaches threshold (is strong enough) or doesn't
nerve cells stimulated
stimulus causes Na+ channels to open
*Na* rusheds in and Na+ channels close (membrane is depolarized)
*this causes K+ channels to open
*K+ rushes out
*K+ channels close

*
what is propagation of action potential
action potential in 1 region stimulates adjacent region
nerve impulse travels down axon
pre synaptic neuron
conducts impulse toward synapse
synaptic cleft
space between 2 neurons at synapse
post synaptic neuron
conducts impulse away from synapse
how does synapse work
*neurotransmitter is released by pre synaptic cleft
*defuses across synapse
*binds to receptors on post synapse neurons
synapsetic transmission
many presynaptic neurons from synapses with same post synaptic neuron
excitatory synapses
stimulate the post synaptic neuron to fire on action potential
inhibitory synapses
prevent the post synaptic neuron from firing a n action potential
what makes up CNS
brain and spinal cord
responsible for higher order of mental function
cerebrum
examples of higher order of thinking
memory learning speech
largest part of brain
cerebrum
how many hemispheres in cerebrum
2
parts of cerebrum
gyrus-ridge
sulcus- shallow groove
fissure-deep grove
longitudinal fissure-seperates the 2 hemispheres
what is corpus collosum
bridge of nerve fibers connecting the 2 hemispheres
how many lobes does each hemisphere have
frontal
parietal
temporal
occipital
cerebral cortex
thin outer layer of gray matter
gray matter
cell bodies and unmyelinated fibers
white matter
tracts of myelinated nervefibers
tracts
bundles of nerve fibers in cns
nuclei
clusters of nerve cell bodies in cns
basal nuclei
subcortical regions of gray matter
what are special senses
receptors located in special sense organs
ex visual receptoers in eye
somatic senses
receptors scattered thru bodie
ex pain receptors
5 special senses
sight, smell, touch(equilibrium), hearing, taste
where do receptors of sense organs send signal to
each receptor sends signals to specific area of cortex
what are somatic senses
temp, pressure, pain, body portion?????
where do receptors of somatic senses send signals
to somatosensory area in parietal lobe
where is somatosensory area in parietal lobe
located in the central sulcus
central sulcus
groove between frontal lobe and parietal
where is the primary somatosensory area
post central area of parietal lobe
where doed each part of body send sensory input to
each part has a specific area
where is primary motor cortex
precentral gyrus of central lobe
where are neurons that control skeletal system
primary motor cortex
diencephalon area
part of forebrain between cerebral hemisphere and midbrain
what is in the area diencephalon
thalmus, hypothalmus and epithalmus pituitary gland choradal plexis
thalmus
relay station for sensory input
hypothalmus
endocrine gland
epithalmus
contains pineal body
chorad plexus
knot of capillaries producing cfs
pituitary gland
endocrine gland inferior to cerebral spinal fluid and hypothalmus
co ordianates voluntary muscle movement
cerebellum
maintains posture and balance
cerebellum
conatains nuclei for visceral function
cerebellum
conatains nuclei for origination of craniel nerves
cerebellum
midbrain
vision and hearing
pons
controls breathing
medulla oblongata
heart rate blood pressure and rate of breathing
nervous tissue is protected by
*bones-skull and vertebrae
*membranes- meninges
*fluid-cerebrospinal
*meninges-membranes covering the brain and spinal cord
kinds of matter
duramater-outer layer of connective tissue
arachnoid-2nd layer
pia mate inner layer, very thin,and closely attached to spinal cord and many blood vessels
ventricles
cavities in the brain continuous with spinal cord
what is in the ventricles
csf
how is csf produced
blood by endothelial cells in choroid plexis
endothelial cells
simple squamous epithelial cells that form lining of blood vessels
subarachnoid space
between arachnoid and pia mater
filled with csf
where do you find csf
circulated throught subarachnoid space, ventricles,and central canal then drains back intoblood
*acts as shock absorber
what is blood brain barrier
formed by tight junction between epithelial cella in capillary walls
what does blood barrier do
prevent difussion of many substances out of blood into brain tissue
what crosses blood barrier
O2 water glucose essential amino acids
what can't cross
metabolic wastes, nonessential amino acids
K+
most drugs
Limbic system
not a specific area
* functional groups of gray and white matter in the cerebrum
what does limbic system control
emotional state, pleassuresensation,motivation
neurons are targets of drug abuse
reticular formation
scattered areas of gray matter in brain
K+ most drugs
what is reticular formation responsible for
responsible for reticular activating system--
reticular activating system
conciousness, awake sleep cycles
coma
where is reticular formation located
extension of brain stem, exits skull at foramen magnum
goes through vertebral column to L2
what is foramen magnum
large opening on inferior aspect of skull,
what is cauda equina
formed from spinal nerves at inferior end of spinal cord
cross section of spinal cord
gray commissure, central copal, nerve tracts, ascending tracts descending tracts, decussation
gray commissure
band of gray matter connecting the 2 sides
central copal
opening thru center where spinal cord goes
nerve tracts
major nerve pathways
ascending tracts
relay info to the brain
descending tracts
carries impulses from brain to effector organs
decussation
crossing of nerve tracts from one side to the other
function of spinal cord
*conduct nerve impulses
*serves as center for reflexes
reflexes
responds to stimuli
3 types of reflexes
involunatary, rapid, predictable
reflex arc
nerve pathways for reflexes
somatic reflex
contraction of a skeletal muscle
autonomic reflex
contraction of smooth or cardiac muscle , secretion from a gland
pupillary light reflex
pupil gets smaller in response to light
what happns if no pupil response to light
poss brain damage
5 special sense receptors location
in brain
what do special sense receptors do
read indo about vision, hearing, equillibrum, taste, smell
photoreceptors
responds to light
mechanoreceptors
responds to movement
chemoreceptors
resond to chemicals
orbit
cavity that houses eye
conjunctiva
mucus membrane covering inner surface of eyelids
conjunctivitis
inflamation of conjunctiva
lacrimal glands
produce tears
6 muscles of eye
superior and inferior rectus
superior and inferior oblique
medial and lateral rectus
3 layers of wall of eye
or tunics(covering)
outer--scalera
middle--vascular
inner
fibrous tunic
center, transparent--cornea
posterior-scalera
vascular tunic
choroid
choroid
contains __________that absorb stray light waves.
cillary body
ring of smooth muscle that changes shape of lens
superior____ligament
attaches cillary body to lens
iris
color part of eye between cornea and lens- controls amt of light entering the eye
???????
opening in iris
retina
contains photoreceptors
sensory receptors for vision
what gives us depth perception
sensory input from each eye goes to both sides of the brain
lens
focuses light onto the retina
far point of vision
farthest distance with clear vision
near point
closest distance of clear focu
when does normal vision occor
when light is focused already on the retina rather then in front or behind
what happens when nearsighted
myopic--elongated eyebal, image focus infront of retina
far sighted
shortened eyeball...image focus behind eyeball
somatic reflex
contraction of a skeletal muscle
autonomic reflex
contraction of smooth or cardiac muscle , secretion from a gland
pupillary light reflex
pupil gets smaller in response to light
what happns if no pupil response to light
poss brain damage
5 special sense receptors location
in brain
what do special sense receptors do
read indo about vision, hearing, equillibrum, taste, smell
photoreceptors
responds to light
mechanoreceptors
responds to movement
chemoreceptors
resond to chemicals
orbit
cavity that houses eye
conjunctiva
mucus membrane covering inner surface of eyelids
conjunctivitis
inflamation of conjunctiva
lacrimal glands
produce tears