Flashcards in Chapter 12 (Part 2) Deck (51):
Unequal charge distribution
Resting membrane potential
ECF has a high concentration of...
ICF has a high concentration of..
potassium ions and negative charged proteins
What is the resting potential of a neuron
Created by uneven concentration of the molecules across the membrane
Created by the attraction between opposing chargesand repulsion from similar charges
Actively move molecules against its gradient
What are the 2 pumps involved in the nervous system?
Na-K and calcium ion pump
Always open allowing ions to diffuse across the plasma membrane
Stimuli causes channels to open which changes the transmembrane potential
Open/close when bound with specific chemicals
Where are chemically gated channels found?
Soma, dendrite, muscle effectors
Open/close in response to change in transmembrane potential
Where are voltage gated channels found?
Membranes that generate action potentials
Open/close as a result of physical stimulation
Where are mechanically gated channels found?
Localized change in transmembrane potential
Change in transmembrane potential from a smaller negative value or positive value
What is depolarization caused by?
Na+ ions rushing into cell
Return to resting transmembrane potential
What is repolarization caused by?
Closing Na+ channels and opening K+ channels to let K+ out of the cell
Change in transmembrane potential making the cell more negative
What is hyperpolarization caused by?
Opening K+ (let out K+) and Cl- channels (let Cl- in)
Change in transmembrane potential that once initiated spread through the entire membrane
What is the threshold membrane potential?
If threshold is met, an action potential will be sent down, if it's not at -55mV, no action potential is sent
Membrane incapable of sending another action potential at this time
Absolute refractory period
Membrane can send another action potential, but with only a large enough stimulus
Relative refractory period
What are the 2 modes of action potential transmission?
Continuous propagation, saltatory propagation
Where does continuous propagation happen?
Where does saltatory propagation happen?
AP moves in tiny steps along the axolemma
Ions cross membrane at nodes
The larger the diameter the _____ AP propagation
Uses ATP to re-establish resting chemical gradients
Sodium potassium exchange pumps
Pups out ___ for every ___ brought back in
3 Na+, 2 K+
Site where neuron communicates with another cell
Presynaptic and postsynaptic membranes are locked together with gap junctions
Axon terminal releases neurotransmitters to communicate with postsynaptic cell
What is the most common type of synapse?
Cell sending signal
Narrow space between cells where neurotransmitters are released
Cell receiving signal
Graded potentials in postsynaptic membrane in response to a neurotransmitter
Cause localized depolarization making postsynaptic neuron closer to threshold
Excitatory postsynaptic potential
What do excitatory potentials open?
Cause localized hyperpolarization making postsynaptic neurons further from threshold
Inhibitory postsynaptic potential
What do inhibitory potentials open?
K+ or Cl- channels
Integration of effect of graded potentials on the postsynaptic membrane
Recurring activation of single synapse