PGY300 Biology Flashcards: Action Potentials & Graded Potentials

Graded potentials originate at the

synapse

Action potentials are produced by _________ ____________ and are initiated at the ___________ _____

graded potentials; trigger zone

The SIZE of the graded potential determines the

frequency of action potentials

The strength of the stimulus determines the

size of the graded potential

Voltage gated Sodium Channel has ___ domains, and in each domain the peptide crosses the membrane ___ times

4; 6 (S1-S6)

S5 and S6 form the

activation gate

Absolute refractory period is determined by

Na channel inactivation

Relative refractory period is determined by

potassium channel after-hyperpolarization

Saltatory conduction

"hopping" of an AP from one node to the next

S4 has a large positive/negative charge?

positive

Hyperkalemia

high potassium in blood, causing a smaller stimulus to create an AP that otherwise wouldn't have occured

Hypokalemia

deficient potassium in the blood causing an AP to not occur at a level that it normally would've

Inactivation gate is formed by

the third cytoplasmic loop (between domain 3 and 4)