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Flashcards in Electrical + Synapic Signalling Deck (8)
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what makes up extracellular fluid

dissolved salts, mostly NA, Cl


what makes up the cytosol

Pottasium (couter ions= protein/RNA)



-60- -75


why is the Vm usually negative

K+ leaks out and their are no channels for - macromolecules so therefore more negative inside


3 different types of ion channels

voltage gated

ligand gated- open when a ligand binds

Leak channels- allow resting cells to be permeable to cations


steps of action potential

1. resting state at -60Mv

2. Na channels open brings Na into cell. reaches threshold potential at -40 and then reaches +40

3. Na closes, K opens and K flows out of cell- hyper polarizes


What is a Gap junction made up of

made up of 6 pro. subunits each called connexin, set of 6 called connexon


steps of transmission of a signal across synapse

1. action potential reaches presynaptic bulb

2.depolarization opens calcium channels

3.increased calcium induces secretion of neurosecratory vesicles

4. neurotransmitter diffuses across synaptic cleft

5. Channels open, letting ions flow into postsynaptic cleft and cause depolarization/ hyperpolarization