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72 Cards in this Set

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  • Back
transmembrane potential (TMP)
difference in voltage between inside and outside of cell
resting membrane potential (RMP)
when the cell is not electrically active
graded potential
any charge that brings a cell out of rest
action potential
generated when graded potential reaches threshold
depolarization
making the membrane more positive
repolarization
returns membrane to resting potential
hyperpolarization
results when potassium ions move out, inside of cell becomes more negative, , making the charge differential
threshold for axon
depolarization of 10-15 mV
all or nothing
You send an impulse via nerve to the motor endplate, where the neurons meets up with the skeletal muscle fiber. If this excitation (via release of ACh) is enough to cross the threshold in the postsynaptic cell (the motor fiber). If this stimuli is strong enough, it will cause a depolarization of the muscle, which causes the sarcoplasmic reticulum to release calcium and cause a series of reactions within the muscle to make it contract. Thusly, if a muscle fiber is activated with a strong enough impulse, it will contract. This contraction is the same strength regardless of the intensity of the neuronal signaling (after it has crossed the threshold for excitation), so the fiber contracts. Your muscle fibers only have one strength, on or off. To vary your lifting, say a heavy object versus a lighter one, you recruit fewer muscle fiber bundles, rather than have all of the muscle fibers contract at a lesser intensity. they can't contract at a lesser intensity, so it is said to be all or none.
afferent division is divided into what two divisions
somatic and visceral sensory
efferent division is divided into what two divisions
somatic nervous system and autonomic nervous system
multipolar neuron services what organ
brain
bipolar neuron services what organs
sensory organs
unipolar services what parts of the body
sensory neurons of the PNS
name three nueron functions
sensory nueron, internueron, motor neuron
function of sensory neuron
carries information from receptor to CNS
internueron function (association nueron)
link between sensory and organ neurons
motor nueron function
carries information from brain to effectors
passive (leak) channel
permanently open
three types of active channels and how they're activivated
mechanical- activitated by pressure/vibration
ligand/chemical- activated by neurons
voltage- activated by charge
name 3 states of gated channels
1) closed but can be opened by stimulus
2) open, activated
3) closed, cannot be activated
four types of glial cells in the CNS
astrocytes, ependymal, oligodentrocytes, microglia
astrocytes
maintains blood brain barrior
ependymal cells
produce CSF
oligodentrocytes
myelinate axons
microglia
fight infections
2 types of glial cells in peripheal nervous system
satellite cells and schwann cells
satellite cells
regulates O2, CO2, nutrient and nuerotransmitter levels around neurons
schwann
provides myelination to axons
threshold for axon
depolarization of 10-15 mV
5 stages of generation of action potential
1) depolarization to threshold
2) activation of Na+ gated channels and rapid depolarization
3) inactivation of Na- channels and activation of K+ channels
4) return to normal permeability
5) refractory period
where is action potential propagated
axon
where are potentials passed onto the next cell
synaptic terminals
relative refractory period
initiation of a second action potential is inhibited but not impossible
refractory period
the amount of time it takes for an excitable membrane to be ready for a second stimulus once it returns to its resting state following an excitation
absolute refractory period
cannot execute muscle contraction at all
continuous propagation of impulse (action potential)
local currents depolarize adjacent areas of membrane so that action potentials continue to form along the membrane
saltatory propagation of impulse
propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials without needing to increase the diameter of an axon.
where is action potential generated
axon hillock
this part of the skeletal muscle cell releases calcium when stimulated by the T tubultes
terminal cisterns of sarcoplasmic reticulum
what type of synapse dominates the nervous system?
chemical
band of connective tissue that surrounds muscles
epimysium
graded potentials can involve either depolarization or hyperpolarization, true or false
T
two types of synapses
electrical and chemical
electrical synapse
no gap between the presyn. and post-synaptic cells, the 2 cells are joined by connexons
2 types of post-synaptic potentials
excitatory post-synaptic potential and inhibitory
excitatory post-synaptic potential
graded depolarization caused by arrival of neurotransmitter at the postsyn. membrane- results from openings of chemically gates membrane channels that lead to depolarization
inhibitory post-synaptic potential
graded hyperpolarization- its inhibited because while hyperpolarization continues, the nueron is inhibited and requireds a larger than usual depolarizing stimulus
2 kinds of summation
spatial and temporarl
spatial summation
potentials arrive at different locations at the same time
temporal summation
potentials arrive at ONE location in rapid succession
in electrical synapses, 2-way transmission of impulses is possible, T or F
T
where can electrical synapses be found?
the brain, including the vestibular nuclei, the eye, and in one pair of PNS ganglia (ciliary ganglia)
function of neurotransmitters
to open or close ion channels that influence membrane that influence membrane permeability
hierarchical arrangement of skeletal muscle
Z-line
z-line sandwiching H-zone
A and I bands
sarcomers
myofibrils
muscle fibers
fascicles
skeletal muscle
each muscle fiber is surrounded by
sarcolemma
myofibrils have how many sarcomers
10,000
muscle fibers are made up of
myofibrials
what role does the elastic prtein titin have in muscle contraction
pulls thin filament towards the M-line in the A band, the I--band (area between successive A-bands) shorten, but the A band remains the same. contraction stops when the Z-line touches the ends of teh thick filaments, at which point the I-band disapears
sarcome is the area between
2 successive z-lines
a sarcomere has how many myofilaments
2, the thick and thin
thin filament has what proteins
actin, nebulin, troponin, tropomyosin
M line
situated in middle and divides the sarcomere into equal halves
thick filaments are attached to the
M-line
thin filaments are attached to the
z-lines
titin connects:
head of the thick to teh z-line which creates 3 zones where the major myofilaments can be found
A-band
runs entire lenght of the thick filamanet on either side of the M-line- has a part where thick and thin overlap
what role does troponin have in muscle contraction
arriving AP stimulates sarcoplasmic reticulum into relasing Ca2+ into sarcoplasm, the extra Ca2+ binds to troponin
a cross-bridge is formed when
a myosin head binds to an active site on the thin filament (f-actin)
twitch
single stimuls-contraction-relaxation sequence in a muscle fiber
twitch can be divided into
latent period
contraction phase
relaxation phase
treppe
if a skeletal muscle is stimulated a 2nd time immediately after relaxation phase, the contraction will develop a slightly higher maximum tension than at the first stimulus. amount of tension produced remains constant, Because the tension rises in stages, its called treppe