Action Potentials

Question 1

Tetrodotoxin (TTX)

Answer 1

Puffer fish toxin that blocks depolarization Na channels

Question 2

Hypocalcemia Effect

Answer 2

Destabilizes closed state of Na channels so lowers excitability threshold and causes spasms (doesn’t affect RP)

Question 3

Hypokalemia Effect

Answer 3

Hyperpolarizes cell membrane potential, so reduced RP and reducing likelihood of AP. Muscle weakness

Question 4

Hyperkalemia 2 Effects

Answer 4

Small [Ko] increase depolarizes, making more susceptible to triggering AP
But larger increase triggers one AP, leaving Na channels inactivated and unable to excite anymore

Question 5

2 Reasons Myelination increases Current Flow

Answer 5

Increases R of membrane and decreases capacitance

Question 6

2 Demyelinating Diseases

Answer 6

Multiple sclerosis in CNS and Guillian Barre in PNS