Nerve Impulse Flashcards
What is the resting membrane potential?
-70mV achived by the Sodium-potassium pump (3 Na+ out for 2 K+ in) during this, Potassium (ungated) channels opened
What is hyperpolarization?
Inside more negative
What is depolarization?
Inside more positive
What does polar mean?
A structure having an uneven distribution of electron density
What are Lingad-gated ion channels?
Found at dendrites and open/close when bound to neurotransmitters
What are Voltage-gated ion channels?
Found in axons and Open/close when membrane potential changes
What are action potentials?
Triggered by a stimulus strong enough to produce a depolarization to threshold
What is the all or non phenomenone?
Neurons either fire maximally
or not at all.
AP Generation #1
When membrane is depolarized, Na+ voltage-gated channels open
AP Generation #2
Na+ influx causes further depolarization, opening more Na+ voltage-gated channels
AP Generation #3
Na+ voltage-gated channels close
AP Generation #4
K+ voltage-gated channels open, allowing efflux of K+, known as repolarization.
AP Generation #5
K+ voltage-gated channels open longer than needed, creating an “undershoot”
What does AP Gen #5 prevent?
second stimulus from depolarizing
membrane.aka the refractory period
What is a synapse?
space between two neurons or between a neuron and an effector
