Cellular membranes are self-sealing— if they are punctured or disrupted mechanically, they quickly and automatically reseal. What properties of membranes are responsible for this important feature?

#Question id: 11207

#Unit 7. System Physiology – Animal

In multiple sclerosis, the myelin sheaths around the axons of the brain and spinal cord are damaged and demyelination results. How does this disease manifest at the level of the action potential?

 I) Action potentials move in the opposite direction on the axon.

 II) Action potentials move more slowly along the axon.

 III) No action potentials are transmitted.

#Question id: 11206

#Unit 7. System Physiology – Animal

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?

#Question id: 11205

#Unit 7. System Physiology – Animal

What would probably happen if a long neuron had one continuous myelin sheath down the length of the axon with no nodes of Ranvier?

#Question id: 11204

#Unit 7. System Physiology – Animal

Why do Na+ ions enter the cell when voltage-gated Na+ channels are opened in neurons?

#Question id: 11203

#Unit 7. System Physiology – Animal

Which of the following statements about action potentials is correct?

#Question id: 11202

#Unit 7. System Physiology – Animal

If you experimentally increase the concentration of K+ inside a cell while maintaining other ion concentrations as they were, what would happen to the cell's membrane potential?