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what is a local grated membrane potential?
stimulus/signal causes a change in membrane potential in a dendrite (gated channels signaled to open)
Threshold potential
threshold or trigger zone or membrane potential that a cell must reach to send the action potential
Excitatory signal
a signal that brings you closer to the threshold
inhibitory signal
signal that brings you further from the threshold
Ionotropic receptors are…
ligan gated ion channels, and membrane potential changes
Metabotropic receptors are…
not ligan gated ion channels, can change gene expression, enzyme activity, and ion movement
____ action potential frequency _____ neurotransmitters in the synapse, thus ______ signal strength
higher, increases, increasing
what determines the absolute refractory period?
the duration that the inactivation gate stays closed
what limits action potential frequency?
inactivation gate on the voltage gated ion channel
What is the absolute refractory period?
the time after the start of an action potential that another action potential cannot be initiated, (inactivation gate stays closed until the end of this period)
What is the relative refractory period?
time from the end of the absolute refractory period to the resting membrane potential
what is (EPSP)?
Excitatory post-synaptic potential: causes post-synaptic cell to have an increase in membrane potential
what is (IPSP)?
Inhibitory post-synaptic potential: causes the post-synaptic membrane potential to decrease
myelin sheath is made up of…
glial cells
Glial cell types (group 1)
Oligodendrocytes (CNS) and Schwann cells (PNS)
oligodendrocytes can myelinate_____ axons
multiple
schwann cells can myelinate ____ axon
one
purpose of myelin on axons
to increase the speed of an action potential
glial cell type (group 2)
Astrocyte (CNS) and Satellite (PNS)
what do astrocytes and satellites do?
support cells neurons by helping to get nutrients to the neuron
glial cell type (M)
Microglia (CNS)- clear out extra protien in extracellular fluid
glial cell types (ep)
Ependymal cells (CNS)- circulate cerebrospinal fluid
2 parts of the nervous system
Afferent (receiving signals) and Efferent (sending signals)
2 parts of efferent nervous system
Somatic (motor) and Autonomic
2 parts of autonomic nervous system
sympathetic and parasympathetic
sympathetics characteristics and actions
higher heart rate, higher blood pressure, higher ventilation, dilated pupils, “fight or flight”, blood towards heart liver and muscles
parasympathetics characteristics and actions
lower heart rate, lower blood pressure, lower ventilation, higher gut motility, constricted pupils, “rest and digest”
what is conduction speed?
speed of an action potential being pushed down the axon
fast conduction speed=
low ratio of (intracellular resistance)/(membrane resistance) * ease of going down axon, less leaks out
slow conduction speed
high ratio of (intracellular resistance)/ (membrane resistance) *harder for the positive charge to go down the axon, more leaks out
2 mechanisms that have increased conduction speed
big axons (increase of diameter has lower intracellular resistance)
Myelinated axons (insulation increases conduction speed)
nodes of ranvier
gaps in between myelin for the ion channels on the axon
What is a ganglion?
cluster of nerve cells in the PNS, act as a relay station
what kind of receptor binds with Acetylcholine in the post-ganglionic cell of the parasympathetic pathway?
Nicotinic Acetylcholine receptor (ionotropic)
what kind or receptor binds with acetylcholine on the target cell in the parasympathetic pathway?
Muscarinic Acetyl choline receptor (metabotropic)
what is released by the pre-ganglionic cell in the sympathetic pathway?
acetylcholine
which receptor binds with acetylcholine in the post-ganglionic cell in the sympathetic pathway?
Nicotinic acetylcholine receptor (ionotropic)
what is released by the post-ganglionic cell in the sympathetic pathway?
norepinephrine
what receptors bind with norepinephrine in the sympathetic pathway?
alpha or beta adrenergic receptors (metabotropic)
where does the pre-ganglionic cell synaps in the adrenal medulla sympathetic pathway?
within the adrenal medulla
what is released by the pre-ganglionic axon in the renal medulla?
Acetyl choline
What types of cells make up the adrenal medulla?
Chromaffin cells (modifed post-ganglionic neurons)
why can’t chromaffin cells synapse with a target cell?
because they dont have an axon
what is released by the chromaffin cells in the renal medulla sympathetic pathway?
the hormone epinephrine
What is the structural difference between epinephrine and norepinephrine?
epinephrine has an extra acytl group
3 muscle types
smoothe, cardiac, skeletal
Cytoskeleton cells are made of…
microfilaments (actin filaments), microtubules, and intermediate filaments
muscles use ___ and ___ to generate force
actin and myosin
which type of myosin is most common in muscles?
Myosin II
Actin and Myosin Generate force through the ______
sliding filament model
Step 1. of the actin filament model
ATP binds to myosin causing myosin to release actin
Step 2. of the actin filament model
Myosin hydrolyzes ATP to ADP and Pi causing the myosin head to extend and rebind actin
Step 3. of the actin filament model
myosin releases Pi causing a power stroke
Step 4. of the actin filament model
ADP is released making room for the subsequent ATP
Temporal summation
integration of several signals in quick succesion
spacial summation
integration of multiple signals received simultaneously at different dendrites
Action potential
an electrical signal propogated down the axon
