Resting and Action Potential, Inhibition Flashcards
propagation
how a nerve will get less/more excited to send signals or messages (how it responds). The agitation of the nerve
Resting potential
static, not excitatory/inhibitory. The environment of a neuron that stops it from sending signals (-70mV)
Why is a neuron’s internal self negative?
because of the primary composition (protien)
concentration gradient:
the distribution of ions inside and outside. Equal distribution of exact substance (remember: neuron wants to maintain equilibrium)
All or nothing phenomenon
a nerve can send one of two things:
action potential (EPSP)
or send nothing (stop excitation, IPSP)
When is the neuron “big, fat, and juicy?”
when the neuron has too much sodium inside it, the neuron wants to have more potassium more than sodium. Following Sodium is water.
electrostatic pressure
more things pumped in the cell, the pressure against the cell wall increases
Ex: If the outside of a cell is more negative, nature wants to reach 0, causing K+ to exit the cell
Action potential (EPSP)
will always be less negative than resting potential.
EX: Adrenaline, threshold is -5mV
the neuron has to reach -5mV in order to release the neurotransmitter
Na+, K+, and Ca+ goes into the gated channels (first at the axon hillock), closing that channel once it reaches -5mV, and reposens another channel to allow the ions to polarize that specific part of the neuron.
-process takes 1/1000th of a second
-once the -5mV stimulates the terminal buton, it releases the neurotransmitter until it reaches its target tissue.
Repolarization
-getting rid of Na and works towards -70 (however, neuron does NOT need to reach resting potential, but it needs to be close)
REFRACTORY PERIODS:
-absolute refractory period: 1-2 ms
-relative refractory period: 1-5 ms+
-RRP (relative refractory period): differentiates people (some have less, other more)
-in order to have conductivity, need message from axon to have refractory period. Disease affects refractory periods
Na/K pump job?
to maintain K+ in neuron because the cell pushes out K+ (bc of net force).
passive transport
diffusion, no energy is required
Which ion is wanted inside the cell in a surplus?
K+ is wanted within the cell than Na+ (Na+ brings in water)
Homeostatic nature of neuron?
-70 mV
-more K+
-less Na+ inside
active transport
requires energy (Na/K pump, against nature)
inhibition
threshold of a greater negative charge than resting potential
EX: GABA, threshold is -110 mV, cell needs to go from -70 to -110
-instead of open gated channels, A CHLORINE PUMP IS OPENED. Cl-
-the more Cl- in, the more negative environment polarizing the section.
***sme thing with refractory period by the concentration gradient opens and kicks out Cl- (electrostatic)
-Na+, K+, Ca+ goes in (repolarization)
