The Nerve Impulse, the Myelin Sheath, and Saltatory Conduction (OCR A-Level Biology A): Quizzes
📚Quizzes
Practise the questions
10 questions from this quiz
ShowHide
Practise the questions
10 questions from this quiz
What is the approximate resting potential of a neurone?
What is the approximate resting potential of a neurone?
-70 mV
How many Na⁺ ions does the sodium-potassium pump move out for every K⁺ ion moved in?
How many Na⁺ ions does the sodium-potassium pump move out for every K⁺ ion moved in?
3 Na⁺ out for every 2 K⁺ in
What is the threshold potential that triggers an action potential?
What is the threshold potential that triggers an action potential?
-55 mV
What membrane potential is reached at the peak of depolarisation?
What membrane potential is reached at the peak of depolarisation?
+30 mV
What membrane potential does hyperpolarisation reach?
What membrane potential does hyperpolarisation reach?
-80 mV
What is one key function of the refractory period?
What is one key function of the refractory period?
Ensures unidirectional transmission
How do neurones encode stronger stimulus intensity according to the all-or-nothing principle?
How do neurones encode stronger stimulus intensity according to the all-or-nothing principle?
Through impulse frequency
What is saltatory conduction?
What is saltatory conduction?
Jumping transmission between nodes
Which cells produce the myelin sheath around axons?
Which cells produce the myelin sheath around axons?
Schwann cells
By approximately how much does myelin speed impulse conduction compared to non-myelinated axons?
By approximately how much does myelin speed impulse conduction compared to non-myelinated axons?
20 times