4.5 Quiz

What happens to Na+ channels at +40 mV?

• They open

• They inactivate

• They close

• They remain unchanged

What is the membrane potential at the threshold level?

• -70 mV

• -50 mV

• +40 mV

• 0 mV

What triggers an action potential?

• When the membrane potential is at rest

• When the threshold potential is reached

• When the cell is hyperpolarized

• When the cell is depolarized

What role does myelin play in nerve impulses?

• Acts as a neurotransmitter

• Serves as an insulator

• Produces action potentials

• Connects neurons

What is the advantage of saltatory conduction?

• Slower transmission

• Quicker process

• Increased energy consumption

• Decreased signal strength

What begins at the Nodes of Ranvier during nerve impulse conduction?

• Synaptic transmission

• Action potential

• Neurotransmitter release

• Myelin production

What is the effect of myelin on the speed of nerve impulse conduction?

• Slows it down

• Speeds it up

• Has no effect

• Stops it completely

What is the primary function of serotonin in the brain?

• Acts as a natural painkiller

• Regulates temperature and sensory perception

• Controls body movements

• Complements actions of epinephrine

Endorphins affect which areas of the brain?

• Sensory perception areas

• Emotional areas

• Motor control areas

• Stress response areas

Where are neurotransmitter molecules stored before release?

• Synaptic cleft

• Synaptic vesicles

• Postsynaptic membrane

• Ion channels