Exam 2 - nervous system - action potential and synapses Flashcards
Name for the net charge (aka potential) across a membrane when neuron is not firing
resting membrane potential
at rest, the intracellular fluid is ______ charged
negatively
the sending neuron is also called the
presynaptic neuron
the receiving neuron is also called the
postsynaptic neuron
at rest, the extracellular fluid around a neuron has higher concentrations of ___ and ___ than the inside
Cl- and Na+
At rest, the intracellular fluid has higher concentrations of _____ and ___ than the outside fluid
potassium and negatively charged protein anions
Once the threshold stimulus is reached, ___ channels open
sodium
Action potential originates from the _____
trigger zone (aka top of axon)
what are the five phases of action potential?
- Local signals sent
- Local signals cause threshold
- Depolarization
- Repolarization
- Hyperpolarization
What part(s) of a neuron send local signals to the trigger zone?
dendrites and body
local signals are also called
graded potential
Sodium channels opening causes the net charge inside the cell to _____. This continues throughout the ____ phase
increase; depolarization
At the end of depolarization, ____ channels start to chose and ____ channels stat to open, which causes the net cell charge to ___
sodium; potassium; drop
_____ is the phase of action potential where the charge goes from positive to negative
repolarization
During this action potential phase, the cell charge goes below its resting state
hyperpolarization
______ ends when ____ channels close and the cell returns to its resting state charge
hyperpolarization; potassium
why do neurons have a net negative charge at rest?
some potassium channels are open which causes positive charge to leave, and negatively charged protein ions are in the cell