10 Questions
Which cells in the brain make dopamine and deliver it to the striatum?
Substantia nigra cells
What is the main symptom of Parkinson's disease related to movement control?
Slow walking
What is the role of potassium ions in resting neurons?
They let some ions out in resting neurons
What happens to dopamine levels when substantia nigra cells die?
Dopamine levels decrease
What causes the resting membrane potential to stay fixed and stable?
The closed sodium channels preventing Na+ ions from entering
What is the result of the axon membrane being depolarized to the threshold of excitation by an EPSP?
Voltage-activated sodium channels open wide, and Na+ ions rush in
Which process marks the end of the rising phase of the action potential?
Influx of Na+ ions triggering the opening of voltage-activated potassium channels
What is the main reason for the membrane potential of a neuron at rest being relatively impermeable to Na+ ions?
Low pressure acting to drive Na+ ions into the cell
What leads to the increase in likelihood that a neuron will fire?
Excitatory postsynaptic potentials (EPSPs)
What is responsible for integrating signals that originate at different sites on the neuron's membrane?
Spatial summation
Study Notes
Dopamine and Parkinson's Disease
- Dopamine is produced by cells in the substantia nigra and delivered to the striatum.
- The main symptom of Parkinson's disease related to movement control is due to the death of dopamine-producing cells in the substantia nigra.
Ion Channels and Neuron Function
- Potassium ions play a crucial role in maintaining the resting state of neurons.
- The resting membrane potential of a neuron is fixed and stable due to the higher permeability of potassium ions compared to sodium ions.
Action Potential and Neuron Excitation
- When the axon membrane is depolarized to the threshold of excitation by an EPSP, it reaches the threshold potential, leading to an action potential.
- The process that marks the end of the rising phase of the action potential is the rapid inactivation of sodium channels.
- An increase in the likelihood that a neuron will fire is led by an EPSP that brings the membrane potential closer to the threshold potential.
Integrating Signals in Neurons
- The process of integrating signals that originate at different sites on the neuron's membrane is performed by the dendrites and cell body of the neuron.
Test your knowledge about Parkinson's disease and its impact on brain function. Explore the symptoms and the role of substantia nigra cells and dopamine in controlling movement.
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