Ch10 Flashcards
(25 cards)
What separates the exterior and interior aqueous environment of cells?
A semipermeable membrane consisting of phospholipids and embedded proteins.
What establishes the electrical difference across the cell membrane?
The disequilibrium of ions inside and outside the cell.
How do ions cross the cell membrane?
Through energy-dependent transport processes and specific pathways.
What happens when a pathway for an ion is opened?
The ion will flow down its gradient.
What is the resting potential of a neural plasma membrane?
~ -70 mV.
What is depolarization?
A phenomenon where the interior of the membrane becomes more positive.
What is the major excitatory neurotransmitter in humans?
Glutamate.
What is hyperpolarization?
A phenomenon where the interior of the membrane becomes more negative.
What are the major inhibitory neurotransmitters in humans?
- Glycine
- γ-aminobutyric acid (GABA)
What type of channels open to generate excitatory signals?
Ligand-gated Na+ channels.
What is a depolarizing graded potential?
The change in membrane potential caused by the opening of Na+ channels.
What is the threshold level for a neuron to fire?
~ -50 mV.
What is an action potential?
The committed firing of a neuron once the threshold is reached.
What initiates an action potential?
The sustained opening of voltage-gated Na+ channels.
What happens to voltage-gated Na+ channels at ~ +30 mV?
They swing into the channel and block further movement of Na+ ions.
How does the membrane repolarize?
By the opening of voltage-gated K+ channels, allowing K+ to flow out.
What is the refractory period?
The time during which hyperpolarization occurs, preventing immediate re-initiation of an action potential.
What causes action potentials to propagate down the axon?
The depolarization at the site of the original action potential raises voltage at the next section of the axon.
What role does Ca2+ play at the axon terminus?
It is required for the exocytosis of vesicles containing neurotransmitters.
What does δ-conotoxin do?
Inactivates voltage-gated Na+ channels in nerves.
What is tetrodotoxin?
A specific blocker of voltage-gated Na+ channels produced by certain bacteria.
How is acetylcholine inactivated in the synaptic cleft?
By the enzyme cholinesterase.
What treatment is used for Attention Deficient Disorder (ADD)?
Inhibitors of norepinephrine and dopamine reuptake.
What is a common treatment for anxiety and depression?
Reuptake inhibitors for serotonin and norepinephrine.
