Nuerons Flashcards
what is the cell membrane?
the semipermeable membrane surrounding the cytoplasm of a cell.
(double layer)
what is polarization of a cell?
difference in electrical charge between the inside and outside of a cell
what is voltage?
the difference in electrical charge between two points
what is resting potential?
A resting (non-signaling) neuron has a voltage across its membrane
what does resting potential charge come from?
ions
what are ions?
any atom or group of atoms that bears one or more positive or negative electrical charges.
- Positively charged ions are called cations; negatively charged ions, anions.
what is negatively charged?
chloride, proteins & amino acids
what is positively charged?
Na+ and K + (sodium and potassium)
why does resting potential occur?
because of the unequal distribution of +/- ions across membrane
what happens to Na+ and K+ during resting potential?
at rest, Na+ is outside the cell and K+ is inside, when nueron fires an abrupt reversal of electrical charge occurs (Na+ and K+ switch)
what is action potential?
A large, sudden and brief reversal in the polarity of a membrane. (an abrupt depolarization (becomes less negative) inside the cell membrane)
why does action potential occur?
when different ions cross the neuron membrane. A stimulus first causes sodium channels to open (Na+). Because there are many more sodium ions on the outside, and the inside of the neuron is negative relative to the outside, sodium ions rush into the neuron.
what are postsynaptic potentials?
a temporary change in the electric polarization of the membrane of a nerve cell (neuron).
what happens during postsynaptic potentials?
chemical transmission of a nerve impulse at the synapse, the postsynaptic potential can lead to the firing of a new impulse.
what do postsynaptic potentials look like?
they are graded (waves)
what are excitatory postsynaptic potentials?
small local depolarization (inside becomes more positive)
what are inhibitory postsynaptic potentials?
small local hyperpolarization (inside becomes more negative)
where do postsynaptic potentials take place?
axon hillock
what is the threshold of excitation?
a level above which any simulation produces a massive depolarization
what is a synapse?
The junction between the most distal (farthest from soma) part of an axon terminal and the membrane of a second neuron.
what are the postsynaptic receptors?
The particular effect of a neurotransmitter on the postsynaptic membrane depends on these
(ionotropic and metatropic)
what is a ionotropic receptor?
open channels directly produce fast action
- opens directly and rapidly when the
correct neurotransmitter molecule binds with it.
what is a metabotropic receptor?
open channels indirectly and slowly to produce longer lasting effects
- This type of receptor opens more slowly, and has longer lasting and more diffuse effects.
what are glial cells?
Cells in the CNS that can become malignant.
what is an axoaxonic synapses?
formed by one neuron projecting its axon terminals onto another neuron’s axon
The part of the neuron that brings information to the soma?
dendrite
what does an axon do?
takes information away from the soma.
This property of the neuron cell membrane creates polarization and the resulting resting potential voltage?
selective permeability
what does depolarization mean?
inside of cell becomes more positive
what does hyper-polarization mean?
inside of cell becomes more negative
what is the name of area in the soma where an action potential is generated?
axon hillock
what is glutamate?
The main “excitatory” neurotransmitter in the brain.
what is spatial summation?
The combination of post synaptic potentials occurring simultaneously at different locations on the dendrite and soma.
(a mechanism of eliciting an action potential in a neuron with input from multiple presynaptic cells)
what are three of the ways that synaptic activity is regulated?
axoaxonic synapses, autoreceptors on presynaptic terminals, and glial cells
What is the resting membrane potential voltage?
-70 millivolts
what are three ways that synaptic activity may be terminated?
reuptake, enzymatic degradation, absorption by glial cells
what is reuptake inhibition?
The pharmacological mechanism by which SSRI’s/SNRI’s work
what is summation?
The combination of potentials in a postsynaptic neuron.
what are microtubules?
This structure of the neuron is involved in transporting molecules and helps the axon maintain its shape
what are autoreceptors?
Receptors found in the presynaptic axon membrane.
