Transmitters and excitability Flashcards Preview

Building the nervous system > Transmitters and excitability > Flashcards

Flashcards in Transmitters and excitability Deck (9)
Loading flashcards...

How does the resting potential change as development progresses

Becomes more negative - result of expression and insertion of new channels and pumps


What work to glia do in order to change the resting potential

Removal of extracellular potassium - from 35mM to 4.5


What happens to input resistance as development continues

Goes down - more current can flow across the membrane due to the increased number of ion channels


What causes the depolarization in an immature neuron

Calcium - action potentials are infrequent and last longer as a result - their delayed action results from the delayed expression of K channels for repolarization


What are delayed rectifiers

A rectifier is a channel that only allows current through one way
Delayed - opens sometime after its voltage threshold has been reached
Outward delayed K rectifiers allow positive charge out of neurons after an action potential
Appearance of these channels shortens the action potential


How do neurons refine the way they respond to activity

By incorporation of different channel types


How do calcium channels change as the neuron develops

Initially are low voltage activated Tcurrents and are rapidly inactivated
Mature channels are high voltage activated N and L currents and remain open for much longer


Where is N-current found

Axon terminals and travel down - control neurotransmitter release


How do GABA receptors change during development

Initially receptors are excitatory - Cl concentrations are higher inside the cell sue to NKCC1 - when the cell depolarizes the Cl moves out instead of in - depolarizing the cell - activates calcium ans sodium channels