Tetrodotoxin Blocks Voltage-Gated Sodium Channels, and Ouabain Blocks Sodium-Potassium Pumps

question 4

Multiple Choice

Tetrodotoxin blocks voltage-gated sodium channels, and ouabain blocks sodium-potassium pumps. If you added both tetrodotoxin and ouabain to a solution containing neural tissue, what responses would you expect?

• A) immediate loss of resting potential
• B) immediate loss of action potential with gradual shift of resting potential
• C) slow decrease of resting potential and action potential amplitudes
• D) No effect; the substances counteract each other.

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Definitions:

Fibularis Longus

A muscle on the lateral side of the lower leg that helps in foot eversion and plantar flexion.

Plantaris

A small, thin muscle in the leg that assists in flexing the foot.

Posterior Thigh

The back part of the thigh, comprising muscles like the hamstrings that are involved in extension of the hip and flexion of the knee.

Biceps Femoris

A muscle of the thigh that is part of the hamstring group, involved in knee flexion and thigh extension.