LC 3-12B Flashcards
All pumps require what to function
energy in the form of ATP
Primary pump used in nervous system
Na+/K+ pumps
Passive channels that are always open, move substances with concentration gradient (high to low concentration) eg sodium and potassium ion channels
leak channels
Channels opened by binding of chemicals neurotransmitters
chemically-gated channels
Channels opened/closed by change in electrical charge
voltage-gated channel
With voltage gated channels, what opens and closes
open and close at two different voltages
Contrast voltage and chemically gated channels
chemically-gated open/close with presence/absence of chemical; voltage open/close at two different voltage numbers
Segment of neuron that receives signals
Receptive Segment
Segment of neuron that contains chemically-gated Na+ and K+ channels
receptive segment
Segment of neuron that starts signals
Initial Segment
Action potential initializes in what segment
Initial Segment
Segment of neuron that carries signals
Conductive Segment
Segment of neuron that contains voltage-gated Na+ channels, voltage-gated K+ channels, and conducts action potential
Conductive Segment
Segment of neuron that transmits signals
Transmissive Segment
Segment of neuron that contains voltage-gated Ca2+ channels, contains Ca2+ pumps
Transmissive segment
Pumps found throughout the entire neuron
Sodium (Na+) and Potassium (K+)
Leak channels found throughout entire neuron
Sodium (Na+) and Potassium (K+)
What type of channels will we find in the initial segment
voltage-gated K+ and Na+ channels, Na+ and K+ leak channels
What type of pumps are found in the transmissive segment
Ca2+ pumps, Na+/K+ pumps
A difference in electrical charge
Voltage (volts)
What creates voltage in a neuron
ions
Amount of movement (force) of charged particles
Current (amps)
Current is movement across what in a neuron
plasma membrane
Opposition to movement of charged particles
Resistance (ohms)
What creates resistance in a neuron
membrane
Current=voltage/resistance, greater current is possible with higher voltage and less resistance
Ohm’s Law
Principle that a neuron either fires or it doesn’t
all or none law
During depolarization, what is added inside the neuron to achieve a positive charge inside the cell
Na+ sodium
What type of channel is used during depolarization to move a large amount of Na+
chemically-gated Na+ channels in the initial segment
Voltage-gated Na+ channels open and sodium rushes in when
when the neuron reaches threshold
What causes depolarization
reaching threshold -55 mV
Occurs at -55mV, the point at which voltage-gated Na+ channels are activated
threshold
The process of Na+ rushing into neuron
depolarization
When do voltage-gated Na+ channels close
at +30mV, the peak of depolarization
When do voltage-gated K+ channels open
at +30mV, the peak of depolarization
The process of K+ potassium rushing out of cell
repolarization
The phase when too much K+ leaves cell and neuron activates Na+/K+ pumps to achieve RMP, uses ATP
hyperpolarization
When are Na+/K+ pumps most active
hyperpolarization
When do you need ATP in a neuron
to reset the neuron to fire again
