Neuronal Communication (OCR A-Level Biology A): Flashcards
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Practise the cards
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Resting potential value in neurones
Resting potential value in neurones
-70 mV
Na⁺:K⁺ ratio pumped by sodium-potassium pump
Na⁺:K⁺ ratio pumped by sodium-potassium pump
3 Na⁺ out : 2 K⁺ in
Threshold potential value
Threshold potential value
-55 mV
Peak membrane potential during depolarisation
Peak membrane potential during depolarisation
+30 mV
Membrane potential during hyperpolarisation
Membrane potential during hyperpolarisation
-80 mV
Two functions of refractory period
Two functions of refractory period
Ensures unidirectional transmission & limits firing frequency
All-or-nothing principle
All-or-nothing principle
Neurone fires fully or not at all; no graded response
Cells that produce myelin sheath
Cells that produce myelin sheath
Schwann cells
Saltatory conduction speed vs non-myelinated axons
Saltatory conduction speed vs non-myelinated axons
~20 times faster
Nodes of Ranvier
Nodes of Ranvier
Gaps in myelin where action potentials 'jump'