F15 Flashcards

1
Q

Nævn betegnelsen for strømmen af de forskellige kaliumkanaler

A

I_to : (transient outwards) Udadgående strøm i fase 1

I_Ki : (K+ inwards) Indadgående strøm i fase 4

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2
Q

Beskriv fase 0

A

Stimulus åbner Na+-kanaler
Ved -65 mV åbnes fast voltage-activated Na+-kanaler
Kanalerne inaktiveres meget hurtigt igen(1-2 ms)

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3
Q

Beskriv fase 1

A

Aktivering af K+-kanaler som repolariserer cellen

Strømmen kaldes I_to

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4
Q

Beskriv fase 2

A

Voltage-regulated calciumkanaler åbner(aktiveres langsommere end Na+-kanaler). Aktiveres ved -20 mV(L-type) og -70 mV(T-type)
Strømmen af Ca+ indad afbalancerer strømmen af K+ udad: plateau

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5
Q

Hvad er inward rectification?

A

gK bliver reduceret både ved positive og negative værdier af Vm

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6
Q

Beskriv fase 3

A

De indadgående K+-strømme forsager repolarisering af cellen

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7
Q

Beskriv fase 4

A

Na,K,ATPasen genopretter den normale tilstand

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8
Q

Hvordan genererer man et slow-respons action potential?

A

Man kan blokere fast Na+-kanaler i fast response fibre

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