nerve impulses: TRANSMISSION Flashcards
When do sodium ion channels open
slight changes in the potential across the membrane
when is a neurone said to be at rest
when it isnt transmitting an action potenital
how does the sodium potassium pump work
2 sodium out for every 3 potassium in
does sodium potassium pump require atp
yes
what electrolyte is the neurone plasma membrane more permeable to, and what effect does this have
potassium, therefore potassium diffuses out the cell
at rest which ions are inside the membrane and which ions are outside
there is potassium ions inside, sodium outside
at rest, what is the charge inside the membrane
inside is negative compared to the outside as there is large anions in the cell cytoplasm
what is the mV of resting potential
-70mV
in myelinated neurones, where does ion exchange occur
at the nodes of ranvier
what happens when sodium ion channels open
sodium ions quickly diffuse down the concentration gradient, causing a depolarisation in the membrane
what is a generator potential
occurs when a small depolarisation is formed by a small sodium ions entering. However not enough to produce action potential
what is a threshold
occurs when depolarisation reaches the specific magnitude of -55mV and causes action potential
what mV needs to be reached inside the cell to transmit action potential
+40mV
what is a voltage gated sodium channel
opened when there is a change in potential difference across a membrane
what is threshold value
- 55mV
