Intro Bio II Exam 3 Nervous System Review

Which change will reproduce the behavior of a neuron exposed to snake venom neurotoxin?

• Blocking voltage-gated K+ channels from opening

• Blocking voltage-gated Na+ channels from opening

• Blocking ligand-gated K+ channels from opening

• Blocking ligand-gated Na+ channels from opening

What does the botulinum toxin do?

• Prevents the release of potassium

• Prevents the release of sodium

• Prevents the release of neurotransmitters

What statement below is true when lidocaine is applied to the middle of the pain receptor?

• The action potential cannot travel through the area with lidocaine, but the pain receptor does release neurotransmitters

• The action potential cannot travel through the area with lidocaine and the pain receptor does not release neurotransmitters

• The action potential can travel through the area with lidocaine, but the pain receptor does not release neurotransmitters

• The action potential can travel through the area with lidocaine and the pain receptor does release neurotransmitters

Explain what a membrane potential is

• The voltage difference between the inside and outside of a cell

• The voltage difference between the inner and outer membrane

• The flow of ions from one side of the membrane to the other

If the cell retains its shape and size but becomes more negatively charged, the membrane potential becomes more ____ (negative / positive)

____ (ligand / voltage / chemical) gated channels open when the electrical difference reaches a certain threshold. ____ (ligand / voltage / chemical) gated channels open in the presence of a signaling molecules

Describe the mechanism of the action of a neurotransmitter:

When the presynaptic neuron is ____ (hyperpolarized / depolarized), ____ (Na / K / Ca) voltage-gated ion channels open, resulting in the release of neurotransmitters. The neurotransmitter crosses the ____ (axon / terminal / synapse) and attaches to the postsynaptic neuron. Depending on the type of neurotransmitter, an excitatory (depolarization) or inhibitory (hyperpolarization) response occurs

At resting potential, which molecule is present more inside the cell?

• Oxygen

• Calcium

• Sodium

• Potassium

Label each of the colored boxes (red, green, blue, and purple) with the correct set or phase during an action potential. Also label the dotted line and the peak

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Answer explanation

- Purple = resting potential

- Red = depolarization

- Green = repolarization

- Blue = hyperpolarization

- Dotted line = threshold of excitation

- Peak = action potential

At each stage of the action potential on the left, explain whether or not the sodium and potassium channels are opened or close. Hint: there should be 1 answer for each of the 4 stages

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Answer explanation