3 - Nervous System Physiology Flashcards
Where are Na+, Ca2+, and Cl- concentrations higher?
extracellular fluid (than they are in the cytoplasm)
where is K+ concentration higher?
in the cytoplasm
what is the Na+/K+ concentration difference maintained by?
Na+/K+ ATPase (primary active transport)
what kind of organic molecules remain trapped inside the cytoplasm?
large, negatively charged organic molecules
what does the special permeability characteristic of the neuron cell membrane to ions occur because of?
ion channels located in the cell membrane
what moves from extracellular fluid into the neural cytoplasm (due to ion channels)?
Na+
what moves from the neural cytoplasm to the extracellular fluid (due to ion channel)?
K+
what kind of ion channels are always open?
non-gated ion channels
A neuron has a higher number of __ non-gated ion channels that __ ion channels.
a neuron has more K+ non-gated ion channels than Na+ non-gated channels.
what is there a greater permeability to when at rest, when only non-gated channels are operational?
there is a greater permeability to K+ than to Na+
why are only non-rated channels operational at rest?
their openness allows them to maintain the RMP.
what kind of channels are import in establishing the resting membrane potential (RMP)?
non-gated ion channels
what type of ion channels are NOT involved under resting conditions?
gated ion channels
what kind of ion channels require a stimulus to open?
gated ion channels
what kind of process do ions in gated ion channels move by?
diffusion, no energy needed (passive process)
what are the 4 reasons gated ion channels can open because of?
- voltage-gated ion channels
- chemically-gated ion channels
- mechanically-gated ion channels
- thermally-gated ion channels
what is it called when gated channels open in response to changes in membrane voltage?
voltage-gated ion channels
what is it called when gated channels open in response to binding of chemical such as neurotransmitters or hormones?
chemically-gated ion channels
what is it called when gated channels open in response to mechanical deformation?
mechanically-gated ion channels
what is it called when gated channels open in response to temperature changes?
thermally-gated ion channels
