Exam 2 Flashcards
A single action potential in a presynaptic neuron is usually enough to get a post-synaptic cell to fire an action potential. (true/false)
False
At current resting membrane potential, the current due to sodium flux is equal to the negative of the current due to potassium flux (assuming the only permeable ions are sodium and potassium). (true/false)
True
Second messengers tend to remain active in a cell long after production or activation. (true/false)
False
The excess negative charge inside cells is lined up next to the plasma membrane. (true/false)
True
The voltage-gated potassium, channel is required for a neuron to repolarize during the action potential. (true/false)
False
At the top of the action potential the membrane is most permeable to which ion?
Sodium
The properties of which channel causes the absolute refractory period?
Voltage-gated sodium channel
The properties of which channel causes the relative refractory period?
Voltage-gated potassium channel
What causes the inactivation of the voltage-gated sodium channel to close?
Depolarization
What causes the voltage-gated potassium channel to close?
Repolarization/Hyperpolarization
Which type of neurons are usually longer in the parasympathetic system?
Pre-ganglionic Neurons
Which type of synapses leads to faster effects in the post-synaptic cell?
Electrical synapses
If the membrane potential is at a stead -55 mV and the membrane is only permeable to sodium and potassium, then what happens to the amount of sodium entering versus the amount of potassium leaving?
The same amount of sodium is entering the cell as potassium leaving
What happens to a neuron when opening sodium channels?
Depolarization
Where are voltage-gated sodium channels concentrated in myelinated axons?
Nodal Membrane
What causes the voltage-gated sodium channel to open?
Depolarization
Which would have the greatest effect on resting membrane potential:
- Changing extracellular potassium concentration
- Changing extracellular sodium concentration
Changing extracellular potassium concentration
Most excitatory post-synaptic potentials are due to the opening of what channel?
Non-specific cation channels
Which division of the nervous system is also called the craniosacral division?
Parasympathetic nervous system
What neurotransmitter binds to a1 receptors?
Epinephrine/Norepinephrine
What cells are responsible for making cerebrospinal fluid?
Ependymal Cells
What receptor is the M2 receptor?
Gi protein-coupled receptor
Post-ganglionic sympathetic neurons primarily release which neurotransmitter?
Norepinephrine
Pre-ganglionic parasympathetic neurons release what neurotransmitter?
Acetylcholine (ACh)
What is the primary inhibitory neurotransmitter in the spinal cord?
Glycine
Which receptors is on adrenal medulla cells?
Nicotinic receptors
Decreasing the concentration of potassium chloride inside a cell would cause the cell…
Depolarize
Increasing the extracellular sodium concentration would cause the membrane potential to…
Become more positive
Increasing the intracellular concentration of potassium and a non-permeable anion would cause the membrane potential to…
Become more negative
What would increasing the concentration of an enzyme do to the rate of reaction for a substrate?
Increase the rate of the reaction at all substrate concentrations
If the cell with a resting membrane of -80 mV does not actively regulate chloride concentrations in the cell, what would be the equillibrium potential (in mV) for chloride in this cell?
-80 mV
What is the equillibrium potential (in mV) for a monovalent anion that has an intracellular concentration of 330 mM and an extracellular concentration of 33 mM?
Eq = (62/-1) log(33/330) Eq = 62 mV
What are two ways to increase conduction speed in an axon?
Myelinate axons
Increasing axon diameter
What is the most effective way of increasing conduction seed in an axon?
Myelinating the axon
What cells make myelin in the peripheral nervous system?
Schwann Cells
