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AP exam 3


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what are graded potentials?
short lived depolarization of the cell membrane to potentially lead to an action potential
the shift from resting potential (-70 mV) to a more positive potential
true or false: dendrites are never myelinated
the CNS contains the
brain and spinal cord
the PNS contains the
things outside the CNS; nerves and ganglia
what is the CNS responsible for?
processing and coordinating sensory data and sending out motor commands
nerves are: (structure)
bundles of axons
ganglia are:
where cell bodies collect
afferent divisions are sensory or motor?
efferent divisions are sensory or motor?
afferent divisions do what?
take info from receptors to the CNS (arriving info)
efferent divisions do what?
take a signal from the CNS to a muscle or gland (exiting info)
damage to the afferent division would cause what?
lack of pain reception; loss of senses
the somatic nervous system is in charge of what?
voluntary muscles; skeletal muscle contractions
the autonomic nervous system is in charge of what?
involuntary; signals to glands, smooth muscle and cardiac muscle
what are the 2 divisions of the ANS?
sympathetic and parasympathetic divisions
what does the sympathetic division do?
fight-or-flight response, arouses the body for action; increases heart rate, respiratory rate, decreases digestion
what does the parasympathetic division do?
rest and digest; calming effect; decreases respirations and heart rate, increases digestion
what are neurons?
nerve cells
how many nucleuses does a neuron have?
one single nucleus
can a neuron divide?
what do neurons NOT have?
centrioles - cannot divide
another word for a neuron's cell body is:
the cytoplasm surrounding the nucleus constitutes the _____
areas of the perikaryon containing clusters of RER and free ribosomes are called:
nissl bodies
what is a dendrite?
branches that extend out from the cell body that receive information to transmit to the rest of the neuron
what is an axon?
process capable of propagating an electrical impulse known as an action potential
the electrical impulse sent through an axon is called:
action potential
the base/initial segment of an axon that is attached to the cell body at a thickened region is called:
axon hillock
extensions of the main axon trunk are called the:
the telodendria of an axon end at the:
synaptic terminal
describe an anaxonic neuron
dendrite and axon are indistinguishable and do NOT produce an action potential
this type of neuron does not produce an action potential
this type of neuron has only one dendrite and one axon and is found in the nose and retina
describe a unipolar neuron
cell body is off to the side and looks fused together
the sensory neurons in the PNS are what classification of neurons?
the most common type of neuron is?
describe a multipolar cell:
one axon, multiple dendrites
all motor neurons and most neurons in the spinal cord are what kind?
does the nervous system provide swift and brief responses or swift and long responses?
in the CNS, a neuron typically receives information from other neurons at its
phagocytic cells in neural tissue of the CNS are
the neural cells responsible for the analysis of sensory inputs and coordination of motor outputs are
depolarization of a neuron plasma membrane will shift the membrane potential toward
0 mV
the primary determinant of the resting membrane potential is
the membrane permeability to potassium
receptors that bind acetylcholine at the postsynpaptic membrane are
chemically gated channels
if the resting membrane potential is -70 mV and the threshold is -55 mV, a membrane potential of -60 mV will make it EASIER or HARDER to produce an action potential?
what do sensory neurons detect?
stimuli - heat, light, pressure, chemical activity
sensory neurons are also known as
afferent neurons
the largest category of neurons are
what do sensory neurons do?
deliver information from receptors TO the CNS
where are sensory neurons located?
motor neurons are known as
efferent neurons
what do motor neurons do?
carry instructions from CNS to effector (muscle or gland)
where are most of the interneurons located?
in the brain
interneurons are involved in:
integrative function, emotions, memory, processing/storing/retrieving info
what are neuroglia?
supporting cells
the 4 types of neuroglia in the CNS are
astrocytes, microglia, ependymal cells, oligodendrocytes
the most abundant neuroglial cells in the CNS are
which neuroglial cell maintains the blood-brain barrier?
what is the blood-brain barrier
keeping blood and the CSF apart
what do astrocytes do?
framework, stabilize tissue to prevent further injury, regulate interstitial environment, maintain blood-brain barrier
these cells keep the CNS free of cellular debris and pathogens
these cells line canals and chambers of brain and spinal cord
ependymal cells
what do ependymal cells do?
line canals and chambers, produce and circulate CSF
these neuroglial cells are epithelial cells
these neuroglial cells wrap around the exposed surface of an axon
oligodendrocytes do what?
create a sheath around an axon
what are the 2 types of neuroglia of the PNS
satellite and schwann cells
statellite cells do what?
surround cell bodies in ganglia, regulate what enters and exits the cell
schwann cells do what?
sometimes they wrap around the axon itself to become myelinated, but most are unmyelinated - the cells are incorporated IN it, not AROUND it.
in an unmyelinated cells, a message must do what?
go through each individual structure
in a myelinated cell, a message must do what?
jump from node to node to send the message
when do myelinated fibers begin and when are they complete?
14th week of fetal development; adolescence
this is the thick outer surface of a schwann cell
gaps between myelinated portions of axons are
nodes of ranvier
what is the function of myelination?
to increase the speed of action potentials
is white fiber myelinated or unmyelinated
why is white matter white?
high white lipid concentration in the myelin
where do we find unmyelinated fibers?
short axons or collaterals
is gray matter myelinated or unmyelinated?
what is demyelination?
the progressive destruction of myelin sheaths in CNS/PNS
is myelin in the CNS or PNS
how permeable is a neuron cell membrane?
selectively permeable
what cells help in PNS regeneration?
schwann cells
what can cause demyelination?
metal poisoning, MS, diptheria, guillain-barre syndrome
what is transmembrane potential?
the potential energy, possible energy, stored energy
when a cell is at rest, is it negative or positive?
ECF is
sodium and chlorine ions are at high levels outside the cells
ICF is
potassium ion and negatively charged protein are high inside the cell
ECF is inside or outside the cell?
ICF is inside or outside the cell?
when does a transmembrane potential exist?
when positive and negative charges are held apart (outside and inside the cells)
when does a current occur in transmembrane potential?
when something happens and the potential difference is eliminated (through charges moving)
a resting potential of a neuron is
-70 mV
is energy required in passive forces?
what is happening in a chemical gradient?
moving from a high concentration to a low concentration
what is happening in an electrical gradient?
moving towards the opposite charge (positive to negative)
in an electrical gradient, the membrane is more permeable to ________
potassium ions
_____ ions leave more quickly than _____ ions enter
potassium; sodium
what is an electrochemical gradient?
the sum of chemical and electrical forces acting on the ion across the plasma membrane (potassium and sodium)
what is the sodium potassium pump?
when the cells expends energy to remove 3 sodium ions and recaptures 2 potassium ions
in the sodium potassium pump, what is leaving and what is coming in?
3 sodium OUT, 2 potassium IN
what are leak channels?
always open, but the permeability varies
passive channels are also called
leak channels
these channels are important in maintaining resting potential
passive/leak channels
active channels are also called
gated channels
what are chemically gated channels?
receptors that are in the cell membrane use neurotransmitters to open the channel
where on the neuron do neurontransmitters open a chemical channel?
at the dendrites and neuromuscular junction
what is a voltage gated channel?
open or close in response to a change in the transmembrane potential
voltage gated channels deal with the movement of
sodium, potassium, and calcium ions
where do voltage gated channels occur?
along axons or sarcolemma
these channels are found only where an action potential is produced
voltage gated channels
what are mechanically gated channels?
open of close in response to a physical distortion (touch, pressure, vibration)
where are mechanically gated channels found?
sensory receptors
how long is the spinal cord
about 18 inches
what are the 2 main spinal cord enlargements
cervical enlargement and lumbar enlargement
this holds the spinal cord in place
filum terminale
the conus medullaris is the
point spot at the spinal cord
the cauda equina is known as the
horses tail
what is the cauda equina made of
NOT the spinal cord, holds nerves
what are the 3 spinal meninges
dura, arachnoid, and pia matters
what is the purpose of the spinal meninges
around the cord to protect it
where is the epidural space?
between the vertebrae and dura mater
this is the fibrous connective tissue forming the outer meninges
dura mater
this is directly attached to the dura mater
arachnoid mater
this is the space that is filled with CSF and acts as a shock absorber
subarachnoid space
the blood vessels in the spinal cord are found in this meninge
pia matter
this is the innermost meninge
pia mater
what is spina bifida?
when bone and skin doesn't grow correctly over the spinal cord
where are most spinal taps taken from
lumbar region
the central canal receives _______ from the _______
CSF from the medulla oblongata
what does the gray commisure connect?
the 2 halves of the spinal cord
sensory nuclei are located where in the spinal cord?
the posterior/dorsal horms
voluntary motor nuclei are located where in the spinal cord?
anterior/ventral horms
visceral motor nuclei are located where in the spinal cord?
lateral horms
these roots come from the anterior horm and contain axons of motor nerves
ventral roots
these roots come from the posterior horn and contrain axons of sensory nerves
dorsal roots
cell bodies of sensory neurons
dorsal root ganglia
what is a mixed spinal nerve?
both motor and sensory axons are in it
white matter of the spinal cord is divided into
do ventral roots bring info in or send info out
send info OUT to PNS
do dorsal roots bring info in or send info out
bring info IN to the cord
white mater is divided into 3 columns:
posterior, lateral, anterior
what are tracts of the spinal cord?
axons that share the same function and structural characteristics
what do ascending tracts do?
take info from the PNS to the CNS - carry sensory info to the brain
what does a descending tract do?
carries info from CNS to the PNS - carries motor commands to the cord (from the brain) and out to the body
this is the outermost covering of a spinal nerve
this divides the axons into bundles/fascicles
this is the covering around each individual axon of a spinal nerve
how many pairs of spinal nerves are there?
how many pairs of cervical nerves are there?
what spinal nerve is between T2 and T3?
what spinal nerve is between C7 and T1?
what is the length of a spinal nerve
very short - 1-2 cm long
branches of spinal nerves are known as
where are neural bodies found in the spinal cord?
the anterior horn
these rami are the smaller of branches
dorsal rami
these rami are for the areas posterior of body trunk and somatic and visceral motor fibers
dorsal rami
these rami are for the limbs and anterior body trunk (organs)
ventral rami
these rami branch off to deal with skeletal muscles, organs, etc.
ventral rami
these are areas of the skin send by a specific spinal nerve
what is a nerve plexus?
a complex interwoven network of nerves formed by ventral rami
what is an example of a nerve plexus?
sciatic nerve, ulnar nerve
what is a reflex?
a rapid, automatic response to specific stimli
what are the 5 steps of the reflex arc?
1. stimulus arrives and receptor is activated 2. a graded potential leads to an action potential, info is sent to the CNS, sensory neuron is activated 3. information processing to a motor neuron 4. activation of a motor neuron 5. response by the effector
what is an acquired reflex?
complex motor patterns like braking your car
when does an innate reflex form?
when you are a fetus
what is a stretch reflex?
tendon stretches
what is a flexor reflex?
a withdrawal reflex
what is a crossed extension reflex?
when 1 side is effected, the other reacts (ex: grab on arm back, the other goes forward)
what are neural pools?
interconnected neurons with specific connections
what are the 2 most common types of circuits?
diverging and converging circuits
what is a diverging circuit?
a broad distribution of specific input and sensory neurons in the CNS - when a single presynaptic neuron travels to more than one post synaptic neuron (ex - eye sends a message to several parts of the brain)
what is a converging circuit?
when many neurons narrow down to one postsynaptic cell - when lots of neurons stimulate one cell
what are reverberating circuits?
follows a pattern - once a stimulus begins at one spot, it will continue to go without much though (ex: we start walking and can continue without thinking about each step)
what is serial processing?
information passes in a line from one neuron to another (most reflexes are this)
what is parallel processing?
info passes down several channels at the same time and allows for more than 1 response at the same time (ex: smelling cookies evokes many different senses)
what is paraplegia?
damage to the thoracic vertebrae or lower - effects lower limbs
what is quadraplegia?
damage at or superior to C5 - the higher up the damage, the more problems will occur)
what is spinal shock?
when the spinal cord is damaged and experiences temporary paralysis
what is poliomelitis?
the virus attacks somatic motor neurons (skeletal muscles) and leads to paralysis
what is meningitis?
inflammation of the meninges of the spinal cord or brain - it disrupts the flow of CSF and causes neural tissue death
what is hansen's disease?
leprosy - bacterial infection of your sensory nerves - you can't feel anything and tend to damage your limbs - your immune response does not react to the damage and infection occurs
what is the mid-brain?
pons and medulla oblongata
what does the diencephalon do?
processing center for emotions and hormones - made of thalamus and hypothalamus
what does the cerebellum do?
allows for repetition of the same movements - involved in balance
this is the site of conscious thought, sensations, intellect and memory
what does the interventricular foramina do?
connects lateral ventricles to the 3rd ventricle
where is the 3rd ventricle found
where are the lateral ventricles?
in cerebral hemispheres - they are in pairs - left and right
what does the mesencephalic aqueduct do?
connects the third ventricle with the 4th ventricle
what does the 4th ventricle become?
the spinal cord
where is CSF produced?
in the ventricles
what are the functions of CSF?
surround and cushion all exposed surfaces of the CNS, transports nutrients, allows brain to float in the skull, provides chemical stability
this is the outermost fibrous covering of the brain
dura mater
what is the first layer of the dura mater in the brain that's fused to the periosteum of cranial bones
endosteal layer
the innermost layer of the brain meninges
meningeal layer
what are the dural sinuses?
the gap between the the dura mater where blood collects to be returns to the heart
what are duralfolds?
area where dura mater dips into the folds of the brain
arachnoid trabeculae does what?
helps return CSF via the blood
what is the final covering of the brain that is everywhere?
pia mater
what are the functions of cranial meninges?
protect the brain, protect the blood vessels, house CSF, partition the brain into individual sections
what does the medulla oblongata do?
coordinates the most basic life functions
where are autonomic nuclei located?
cardiovascular center and vasomotor center and respiratory center
what does the vasomotor center do?
controls smooth muscle tone in blood vessels
what are the replay stations of the medulla oblongata?
places where synapses happen and send info to the thalamus or cerebellum
where are groups of nuclei located in the brain?
medulla oblongata
this links the cerebellar hemispheres with the rest of the brain and acts as a bridge
where is the respiratory control center located in the brain?
the pons
the right and left cerebellar hemispheres are connects by the
where are purkinje cells located?
the cerebellum
these cells can receive 200,000 synapses per cell coming from all over the body
purkinje cells
tree of life
arbor vitae
what is the arbor vitae made of
white mater - axons
what does the arbor vitae do?
sends info to both sides
what is the function of the cerebellum
learned movement patterns, coordinate muscles of balance and equillibrium
what is ataxia
damage to the cerebellum - it can be temporary (drunk) or permanent (from trauma)
what are the 2 parts of the corpus quadrigemina
superior colliculus and inferior colliculus
what is the superior colliculus in charge of
visual information and reflex movements of the eye, head and neck
what is the inferior colliculus in charge of
reflexes of auditory system
what is the substantia nigra
darkly pigmented; inhitis cerebral activities by releasing dopamine and inhibits muscle tone
what does a red nucleus of the mesencephalon do
receives info from cerebrum and cerebellum has subconscious control of upper limb position and muscle tone
what are the 2 specialized structures of the hypothalamus
mamillary bodies and infundibulum
what do mamillary bodies of the hypothalamus do
process olfaction and reflex movements of eating
what does the infundibulum from hypothalamus do
narrow stalk of tissue connecting hypothalamus and pituitary gland
what are the functions of the hypothalamus
autonomic control to adjust for activities, emotional response and behavior, body temperature, food and water intake, sleep-wake cycle, memory
what does the thalamus do?
receives, filters, sorts and relays sensory impulses to the appropriate cortical area, coordinates info from the hypothalamus, cerebellum for motor commands
what does the pineal gland secrete?
melatonin (helps with sleep cycle)
the hippocampus and the ammygdyla is part of the
limbic system
where are the hippocampus and ammygdyla found?
in the temporal lobe
what does the cingulate gyrus do?
arches over the corpos collosum
what is the fornix?
tract of white mater that connects the hippocampus with the hypothalamus
what is the main purpose of the limbic system?
the emotional part of the brain
the largest part of the brain
this is on the outer edge of the cerebrum
cerebral cortex
the cerebral cortex is made of
grey mater
these are the ridges that you see on the cerebrum
this is the deep groove that divides the cerebrum into 2 hemispheres
longitudinal fissure
this is the shallow indendation that divdes the parietal and frontal lobes
central sulcus
motor commands are sent from this area of the brain
frontal lobe
this area is behind the central sulcus and is in charge of primary sensory info
parietal lobe
this lobe has auditory and olfactory information
the occipital lobe is in charge of
visual information
the insula is in charge of what?
taste information
what does cerebral white matter do?
connects areas of grey matter - white matter are the axons that connect the areas of the cerebral cortex
commissural fibers do what?
connect hemispheres for communication - so the left side knows what is happening on the right and vice versa
this area of the brain has more than 200 million axons
corpus callosum
these fibers interconnect areas of the neural cortex within a single hemisphere
association fibers
these fibers link the cerebral cortex to the rest of the CNS
projection fibers
what are basal nuclei?
masses of gray matter
where are basal nuclei found?
imbeded into the core of the cerebrum
what are the functions of basal nuclei?
subconscious control of muscle tone, coordination of learned movement patterns
will the basal nuclei begin a general pattern?
NO - the cerebrum will begin it, the basal nuclei have the pattern
this part of the cerebral cortex is anterior to the central sulcus
primary motor cortex
what does the primary motor cortex do?
directs voluntary motor neurons in the brain stem
the premotor cortex is for
coordination of learned movements (like a reading pattern)
this area is for sensing touch, pressure, pain, vibrations and temperature and is at the parietal lobe
primary sensory cortex
the region that monitors and interprets info that arrives at the sensory areas of the cortex
somatosensory association area
this area recieves visual information
primary visual area
this area interprets the results of the primary visual area
visual association area
the gustatory cortex is the info from the
taste buds
this area receives info from association areas and direct very complex motor activities
integrative center
this area helps with predictions and consequences
prefrontal cortex
this area of the brain is where our personality and analysis abilities comes from
wernicke's area
what does the broca's area do?
regulate pattern for breathing and vocalizations for speech
the left side of your brain functions as
language, reading, writing, analytical, logic and reasoning
the right side of your brain is for
analyzing emotional context, how you say something, facial recognition
excessive CSF in the brain
impairs the ability to speak or read
this happens when the corpus collosum is cut
disconnection syndrome
when the brain bangs against the cranial bones and bruising occurs it is
a concussion
ALS is also known as
lou gehrig's disease
what happens with ALS/lou gehrig's?
spinal nerve becomes diseased and stops working - death usually occurs because the respiratory muscles stop working
what does ALS stand for?
amyotrophic lateral sclerosis
excess potassium ions in the extracellular fluid decrease the chemical gradient for potassium which interferes with repolarization and inhibits action potentials
will a fever cause the cell membranes to be more or less excitable?
with hypothermia cause inhibition of excitement of neural activity
what happens during a stroke?
oxygen is depleted from the CNS and portions of it die
what does botox do?
blocks neurotransmitter release and relaxes the muscle
what does black widow spider venom do?
increases the neurotransmitter release and causes spastic paralysis (your muscles can't relax)
this is the most widespread neurotransmitter used in ALL neuromuscular junctions
where is acetylcholine found?
what does dopamine do?
causes excitatory of inhibitory effects - it helps prevent overstimulation
norepinerphrine does what?
adrenaline! causes excitatory effects
what does serotonin do?
excitatory effect in the CNS
if you have a decreased level of serotonin, what symptoms might you have
less concentration and depression
where is norepinerphrine found?
the brain and ANS
where is dopamine found?
part of the CNS
what does GABA do?
inhibitory effect, helps reduce anxiety
how does GABA work?
hooks into calcium channels and inactivates them, less neurotransmitter is released so the message doesn't get sent
this neurotransmitter relays pain sensations and is a vasodilator
substance P
opoids are created in the _____ and controlled by the _______
pituitary gland; hypothalamus
what do opoids do?
provide pain relief by inhibiting the release of neurotransmitters
what are postsynaptic potentials and where do they develop?
they are graded potentials that develop in the postsynaptic membrane
EPSPs are
excitatory post synaptic potentials
what do EPSPs do?
cause depolarization of the postsynaptic membrane and move closer to threshold
excitatory synapses produce
IPSPs are
inhibitory postsynaptic potentials
what do IPSPs do
cause hyperpolarization of the postsynaptic membrane - it gets more negative
excitatory synapses cause depolarization by
opening the channels that allow both sodium and potassium to cross the cell membrane, which decreases negative ions and gets MORE positive
how do inhibitory synapses cause hyperpolarization?
channels that allow potassium and/or chloride ions open and allow them to cross the membrane - potassium will exit or chloride will enter - gets more NEGATIVE
what happens at the summation of the postsynaptic neurons?
combo of EPSPs or IPSPs or BOTH
in this summation, stimuli occur in rapid succession and single synapses are activated repeatedly
temporal summation
at this summation, simultaneous stimuli at different locations of the same neron have the same effect
spatial summation
facilitation is when
a neuron is closer to threshold than when it's at rest
what would caffeine do to a threshold?
decreases it, the amount of Ach is increased and there are faster action potentials
is nicotine a EPSP or IPSP
what causes a graded potential?
a stimulus opens gated ion channels
these are changes in transmembrane potential that can't spread far from the site of stimulation
graded potentials
this is a shift away from resting potential to becoming MORE negative
what happens during hyperpolarization?
potassium gated channels open
this is when gated channels close and the sodium potassium pump and leak channels return ion concentrations back to normal resting potential
what is the purpose of a graded potential?
to initiate an action potential if it's strong enough
action potential only occur in these cells
neurons and muscle cells
once stimulated, can you stop an action potential?
this is the rapid reversal of membrane potential
action potential
to have an action potential, you must have a stimulus that's great enough to:
open voltage regulated channels
what is the all-or-none principle?
once threshold is reached, you have the same action potential each time
the difference between graded potentials and action potentials is
the all-or-none principle
what is the threshold for a sodium gated channel?
-60 mV
what are the 4 steps of an action potential
1. graded potential causes depolarization (making more positive) to reach threshold 2. sodium ions rush into the cell to make it positive 3. at +30 mV, sodium channels inactivate and the potassium channels open up and potassium leaves 4. the cell returns to normal permeability (temporary hyperpolarization)
at the end of an action potential, why is there temporary hyperpolarization?
-90 mV because potassium ions move out at a faster rate than when at rest.
the time it takes the cell membrane that has undergone an action potential to stabilize
refractory period
what happens in the absolute refractory period
can't undergo another action potential because the gates are inactivated
what happens during the relative refractory period?
if a great enough stimulus comes along, than it will generate another action potential even if it's not at rest
what is the role of the sodium-potassium pump during the refractory period?
the channels must open
where will an action potential travel?
away from its point of origin until the end - it doesn't fizzle out
this is when an action potential is "retold" along an entire unmyelinated fiber
continuous propagation
this is when an action potential jumps from node to node of a myelinated fiber
saltatory propagation
what are type A axons?
largest, myelinated, responsible for sending info related to position, touch and balance, they move very fast
what are type B axons?
smaller, myelinated, responsible for sending info related to temperature, pain, general touch, about 18m/sec
what are type C axons?
smallest ones, unmyelinated - smooth and cardiac muscle and glands, travels the slowest at about 1m/sec
are action potentials in skeletal muscle or muscle tissues?
muscle tissues
what is the resting potential in muscle tissue?
-85 mV
an action potential will last longer or shorter in muscle cells?
are the action potentials in muscle tissue fast or slow?
the transfer of information from the axon to a postsynaptic cell is called
the synapse
this kind of synapse is when pre and post synaptic cells are locked together in a tight junction
in this synapse, there is no direct connection between pre- and post-synaptic cells
chemical synapse
if there is a chemical synapse, will an action potential occur?
not necessarily
this is the fluid filled space between the axon terminal and membrane
synaptic clefts
if a presynaptic neuron's axon terminal is excitatory, what will happen?
promote action potential
if a presynaptic neuron's axon terminal in inhibitory, what will happen?
action potential will be supressed
excitatory neurotransmitters cause
inhibitory neurotransmitters cause
what happens during a typical cholinergic synapse?
1. action potential arrives and depolarizes the synaptic terminal 2. depolarization opens calcium channels in the presynaptic membrane 3. calcium ions flood into presynaptic cytoplasm and triggers the exocytosis of synaptic vesicles 4. synaptic vesicles fuse with the membrane of the axon terminal and ACh is released into the synaptic cleft 5. ACh binds with receptors in the postsynaptic membrane 6. Ion channels open and the postsynaptic membrane is depolarized 7. this creates a graded potential which can lead to another action potential
what will ACh be degraded by in the postsynaptic membrane and synaptic cleft?
this is the time it takes between the arrival of the action potential to the postsynaptic membrane
synaptic delay
all receptors of ACh are _______ and cause ______
excitatory, cause depolarization
neurotransmitters will be excitatory or inhibitory dependent on the
why do neurotransmitters have to be removed from the synaptic cleft?
for future action potentials to occur
these help influence the release of neurotransmitters by the presynaptic cell or postsynaptic cell's response to the neurotransmitter
do neuromodulators stay a long time?
YES - they don't go away easily
most neuromodulators bind to ______ or _______ and activate _______
presynaptic or postsynaptic and activate enzymes (to influence the chemically-regulated channels)
A dorsal and ventral root of each spinal segment unite to form a
spinal nerve
The white matter of the spinal cord contains
bundles of axons
The dorsal root ganglia mainly contain
cell bodies of sensory neurons
The specific strip of skin that is innervated by a specific spinal nerve is called a(n) ________.
The complex, interwoven network formed by contributions from the ventral rami of neighboring spinal nerves is termed a(n)
The ________ plexus supplies innervation to the diaphragm.
Reflexes based on synapses formed during development are ________ reflexes.
The part of the peripheral nervous system that carries sensory information to the CNS is designated
The myelin sheath that covers many CNS axons is formed by
Cholinergic synapses release the neurotransmitter
If the chemically gated sodium channels in the postsynaptic membrane were completely blocked,
synapses would completely fail
Small, wandering cells that engulf cell debris and pathogens in the CNS are called
Voltage-gated channels are present
in the membrane that covers axons
In a(n) ________ synapse, current flows directly between cells.
the adult spinal cord extends only to
the first or second lumbar vertebrae
true or false: gray matter is primarily involved in relaying info to the brain
a sensory region monitored by the dorsal rami of a single spinal segment is
a dermatome
the synapsing of several neurons on the same postsynaptic neuron is called
an example of a stretch reflex triggered by passive muscle movement is the
patellar reflex
the subarachnoid space contains
ascending tracts carry
sensory info to the brain
this site of CSF production is the
choroid plexus
this contains tracts that link the cerebellum with the brain stem
the pons
CSF is produced and secreted by what kind of cells
ependymal cells

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