Bad Fish case study

What which of the following is considered the nerve impulse that is the main communicative signal in neurons?

• a hypopolarizatioer

• an action potential

• a graded potential

• an undershoot

• all of the above

An action potential travels down what part of a neuron?

• dendrites

• cell body

• axon

• all of the above

• none of the above

The movement of charged ions based on concentration gradients when the nerve is at rest….

• Both Na+ and K+ will move OUT of the cell.

• Both Na+ and K+ will move INTO the cell.

• Na+ will move OUT and K+ will move INTO the cell.

• Na+ will move IN and K+ will move OUT of the cell.

• Neither Na+ nor K+ will move across the cell membrane via diffusion

When a neuron is stimulated, the area of the membrane at the point of stimulation becomes more permeable to Na+.

• The membrane voltage will become < -70mV, because Na+ will move OUT of the cell

• The membrane voltage will become >-70mV, because Na+ will move OUT of the cell.

• The membrane voltage will become < -70mV because Na+ will move INTO the cell

• The membrane voltage will become >-70mV because Na+ will move INTO the cell

At the peak of the action potential, Na+ voltage-gated channels close, and K+ voltage-gated channels open in response to positive membrane potential.  To return the cell to its negative resting potential quickly:

• .K+ will diffuse along its concentration gradient INTO the cell.

• K+ will diffuse along its concentration gradient OUT of the cell.

• Na+ will reverse its direction of diffusion OUT of the cell.

• The sodium-potassium pump will move Na+ OUT of the cell and K+ INTO the cell

• None of the above would return the cell to its negative resting potential quickly.

Dr. Westwood ate a meal of pufferfish and rice.  As a result, he was a victim of pufferfish poisoning that caused his life-threatening symptoms of numbness, paralysis, irregular heartbeat, and difficulty breathing. Tetrodotoxin (TXX), found in pufferfish flesh, is a molecule that:

• Blocks the release of neurotransmitters.

• Kills T cells

• Blocks voltage-gated sodium ion channels.

• Blocks neurotoxins

• Causes widespread blood clotting.

If tetrodotoxin (TXX) blocks voltage-gated sodium ion channels, which part of the action potential would be impacted?

• A

• B

• C

• D

• more than one of these

Dr. Westwood experienced numbness after eating the pufferfish meal because TXX causes:

• Motor neurons to fire continuously, overloading the brain with signals, resulting in numbness

• Motor neurons to stop firing, preventing communication with the brain, resulting in numbness

• Sensory neurons to stop firing preventing communication with the brain, resulting in numbness.

• Sensory neurons to fire continuously, overloading the brain with signals, resulting in numbness.

• None of the above explain why Dr. Westwood experienced numbness after his pufferfish meal.

Why did Dr. Westwood experience paralysis after eating the pufferfish meal?

• TXX causes motor neurons to fire continuously, overloading the brain with signals, resulting in paralysis.

• TXX causes motor neurons to stop firing, preventing communication with the muscles, resulting in paralysis.

• TXX causes sensory neurons to stop firing preventing communication with the brain, resulting in paralysis.

• TXX  causes sensory neurons to fire continuously, overloading the brain with signals, resulting in paralysis

• None of the above explain why Dr. Westwood experienced paralysis after his pufferfish meal.

What symptoms did Dr. Westwood experience after both his pufferfish meal and after handling the new bird species?

• Nausea

• Numbness

• Paralysis

• Difficulty breathing

• More than one of the above