Flashcards
how neurons work- lecture 2
Flashcards do conjunto (39)
- 1what is the membrane resting potential of a cellelectrically negative on the inside compared to the outside
- 2what is the membrane (resting potential) of the cell-65mV
- 3what ions help maintain the membrane potential of the cellsodium
calcium
potassium - 4in the resting potential what are the general rules for the concentrations of these ions?concentration of potassium greater on the outside of the cell than the inside
sodium and calcium are more concentrated on the outside of the cell - 5what channels are used to maintain the resting potential of the neuronssodium potassium pump
calcium pump - 6at resting potential what ion channel is open in the membraneK+
- 7what is the net movement of ion through these channelscalcium moves out of the cell
- 8what effect does the net movement of potassium have on the establishing of a resting potentialK+ moves out of the cell and the cell is negatively charged
- 9what effect does a stimulus have in the membrane of a neuronechanges the conformation of some membrane proteins that allow different ions to cross the membrane
- 10what would be the effect of the opening of a potassiumm ion channel on the membrane at resting potential-net movement of the K+ out of the cell leads to the cell becoming more negative
HYPERPOLARIZATION - 11what would the effect of the opening of a sodium channel on a cell the is in resting potential?Na+ diffuses into the cell
-the cell becomes less negative
-DEPLOARISATION - 12what does a stimulus trigger to cause an action potentialopening of sodium channels
-cell depolarisation - 13what effect does the opening of the sodium channels have on the cellcell becomes more positive
- 14what must be reached for the action potential to be triggeredthreshold
- 15what happens once the threshold has been reached what stage of the action potential is this?more sodium channels open
-more sodium (Na+) enters the cell
this is the rising stage of the action potential - 16what are the 4 stages of the action potent l (graphically)-rising stage
-overshoot
-falling phase
-undershoot - 17what happens during the overshoot phase-the cell has so many Na+ that it is positive charged on the inside compared to the outside
- 18describe the falling phasesodium on the inside of the cell begins to equilibrate with that on the outside of the cell
-sodium channels triggered to close - 19describe what happens at the same time as the closure of the sodium channels?potassium channels open
-net movement of K+ out of the cell
-cell becomes more negative - 20what are the name given to the potassium ionsdelayed rectifiers
- 21why are the potassium ions named delayed rectifiersthere is a delay in their opening a closure
-their delayed closure means that move potassium leaves the cell than is necessary
hyper polarisation of the cell - 22what is the relative refractory periodcaused by the undershoot
-the cell needs more sodium to enter the cell to reach the threshold
-makes it harder for the action potential generation - 23what is the absolute refractory periodsodium channels need time to recover before they can open again
- 24what allows the quick travel of the action potentialsmyelination by the oliodendria and Schwann cells
- 25what are the periodic breaks in the myelination callednodes of ranvier
- 26what are contained on the nodes of ranvier?high levels of Na and K channels
- 27what disease is caused by the loss of the myelination of the axon of neurons in the CNS causing the slowing of propagationmultiple sclerosis
-leads to impaired speech and vision - 28what is the effect of an action potential in the presynaptic celldepolarises the presynaptic terminal
- 29what is the effect of depolarisation of the axon terminal in synaptic transmission?fusing of vesicles that contain neurotransmitters
- 30what happens on the post synaptic cell in synaptic transmissionreceptors on the membrane of the post synaptic cell are specific to certain neurotransmitters
- 31On which part of the cell are the post synaptic neurotransmitters founddendrites of the postsynaptic cell
- 32what is the effect of the depolarisation of the presynaptic cellterminal becomes depolarised
-voltage gated calcium ion channels open
-large influx of calcium enter the cell - 33name the process that causes the vesicles to fuse with the presynaptic membraneexocytosis
- 34what are the two different receptor types that the neurotransmitters may bind with on the post synaptic celltransmitter gated channels (inotropic receptors)
G protein coupled receptors (metabotropic) - 35describe the action of the inotropic receptors (transmitter gated channels)usually consists of 4/5 subunits
form a pore through the membrane
binding of a neurotransmitter causes a change in the conformation - 36If the inotropic receptor is said to be excitatory what response does it have to the binding of a transmitteropens the Na+ channels on the membrane
-membrane potential becomes more positive and closer the threshold - 37If the inotropic receptor is said to be inhibitory what response does it have to the binding of a transmittercauses the opening of Cl- channels on the membrane
-cell becomes more -
further from the threshold - 38describe the action of the G protein coupled receptors of neurotransmittersbinding to the receptor causes the activation of G proteins
-these activate effector proteins
these could be ion channels or could be proteins that make secondary messenger signalling pathways
-wide changes within the cell - 39types of transmitters
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- bl1102 biology FlashCards sobre how neurons work- lecture 2 , criado por Samantha Bruce em 15-05-2018.
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- Samantha Bruce
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