Properties of the Neuron
What structures are part of the CNS?
brain and spinal cord
What does the equilibrium potential of a neuron describe?
the membrane potential at which the ion has no driving force
What type of molecule binds to a receptor?
Ligand (ex: drugs, neurotransmitters)
What type of drug increases the function of a receptor?
Agonist
Draw a neuron and identify its key structures
(show picture)
After hyperpolarization of the neuron during the undershoot of an action potential, how does the neuron return to rest?
the sodium-potassium pump continuously moves three Na+ ions out of the cell and two K+ ions into the cell
What allows calcium to enter axon terminals?
An action potential depolarizes the membrane and opens the voltage-gated calcium channels
Which drug reduces the function of the NMDA receptor?
Ketamine
How does DNA result in a protein? List the two main steps and provide brief descriptions
transcription (where a copy of DNA called mRNA is created in the nucleus) and
translation (where mRNA is read by a ribosome to create a protein)
When voltage-gated Na+ channels open during an action potential, which way does Na+ flow and why?
Na+ flows into of the cell because of strong electrostatic and diffusional forces
What distinguishes electrical transmission from chemical transmission?
In electrical transmission, ions flow faster, no NT release occurs, the separation between the pre and post neuron is smaller, and there is direct passing of electric current
If a drug is referred to as a positive allosteric modulator of glutamate receptors, what would its effect be?
It would enhance the effects of glutamate without directly binding to the receptor site
If a neuron became unmyelinated, how would its neurotransmission be impacted?
the conductance of an action potential would be slowed down
In a neuron resting at +30 mV, how would diffusion and electrostatic force act on potassium?
Both forces would be driving K+ out of the cell. Since K+ is more concentrated inside a resting neuron, diffusion would drive K+ out of the cell. Because the current membrane potential is +30 mV, and K+’s equilibrium potential is -80mV, the electrostatic force pushes K+ outside the cell to “balance” out the charge.
What is the difference between spatial and temporal summation?
Spatial summation is when EPSPs from multiple sources add together, while temporal summation is when a single source transmits multiple EPSPs
What neurotransmitter relies on the enzyme tyrosine hydroxylase, only binds to metabotropic receptors, and is key for motivation?
Dopamine
Name the five main glia types and their functions
Astrocytes- insulate synapses, BBB support, reuptake, ion concentrations
Oligodendrocytes- produce myelin sheath in the CNS
Ependymal Cells- produce CSF, line ventricles
Schwann Cells- produce myelin sheath in PNS, cell regrowth
Microglia- breakdown neurons, inflammatory response
What would happen to the action potential if the extracellular concentration of sodium was greatly reduced?
Less sodium would enter the neuron because the concentration gradient would be reduced, so the depolarization would be smaller
What would happen if neurotransmitters were NOT removed from the synaptic cleft?
Neurotransmitters would continue to activate/stimulate receptors on the postsynaptic neuron
What are the two ways GABA gets cleared from the synaptic cleft?
uptake by astrocytes and reuptake by GABA transporters