neurons & glia
Neurons send information through ___ and receive input through ___.
Axon, dendrites
What is the threshold potential and what does it do?
-55mV, initiates AP
Define net driving force.
Combination of diffusional and electrostatic forces on a particular ion, drives ion movement
What type of postsynaptic potential INCREASES the possibility of another action potential at the postsynaptic neuron?
EPSP (Excitatory Postsynaptic Potential increases it because it depolarizes the cell)
What kind of receptor results in a cascade of events and can indirectly generate a PSP with a slow response?
Metabotropic receptor
Which glia is responsible for maintaining the blood-brain barrier?
astrocytes
Depolarization is seen in the ___ phase.
Rising
When a neuron is at rest, which direction is sodium’s driving force?
Into the cell
Name 3 characteristics of IPSP.
Polarizing
Flow of NEG ions
Generated by GABA
Makes an AP is less likely
Which neurotransmitter cannot be removed from the synaptic cleft via reuptake or uptake?
acetylcholine
Why do some people compare a neuron to a banana in a salty, milky pool?
CSF filled with Na+, Cl-, Ca++
Lot of K+ inside cell
The _____ ______ period prevents an AP from immediately being triggered again because the cell is hyperpolarized. Another AP is unlikely, but technically possible.
Relative refractory period
Explain the electrostatic and diffusional forces on a potassium ion when a neuron is at rest.
Electrostatic: enter neuron (bc cation and neuron is -65mV)
Diffusion: exit neuron
The flow of what 2 ions cause the initiation of an EPSP?
Na+ and Ca++, because EPSP involves the flow of POS ions due to the generation of glutamate
How does communication of chemical synaptic transmission differ from electrical synaptic transmission?
Electrical: fast and simple (direct electrical current) communication
Chemical: Communication through neurotransmitters
What did Santiago Ramon y Cajal contribute to neuroscience?
Drew neurons, believed brain made of individual neurons that connect to each other
Explain the role of nodes of ranvier in AP propagation.
Points of regeneration
High [ ] of Na+ channels
Gaps in myelin
What would drive chloride to enter the cell if the potential is at -20 (hypothetical situation)?
Diffusion force
What are the two main differences between spatial and temporal summation?
Spatial:More efficient, Multiple neurons
Temporal:Less efficient, Multple inputs from a single neuron
Name the NTs synthesized from tyrosine.
Dopamine, epinephrine, norepinephrine (catecholamines)
Name 3 differences and 1 similarity between schwann cells and oligodendrocytes.
Similarity:both provide myelin.
Schwann cells: PNS, each cell is just 1 myelin segment, repair
Oligodendrocytes: CNS, 1 oligodendro. produces myelin sheath for many axons, CANT repair
A person takes a pill that inhibits their sodium channels, so they cannot open. How does this affect the brain?
An action potential cannot be initiated/it would affect the rising phase
If the cell potential is at HYPOTHETICALLY –80 mV and K+ channels were to open, what would be the driving force of the K+ ions?
NONE bc they’re at equilibrium
There is an influx of Cl- in the postsynaptic membrane. Explain what PSP occurred, the neurotransmitter(s) was involved, polarization of the cell and effects on further AP.
- IPSP
- GABA
- Polarized
- Less likely for an AP to occur.
If the same amount of Na+ and Cl- are on the OUTSIDE of the cell, explain the forces acting on Na+.
Hint: A little bit of both forces, but in what ways?
Diffusional: Na+ wants to go inside the cell through diffusion
Electrostatic: Since the # of Cl- is equal its negative charge pulls Na+ outside of the cell