The Neuronal Membrane At Rest Flashcards
(29 cards)
resting membrane potential
Membrane has a more negative electrical charge compared to the outside
What happens during an action potential?
During an action potential, there is a brief reversal of the membrane potential at rest, causing the inside of the membrane to become positively charged relative to the outside.
Fluid inside the neuron is
intracellular fluid or cytosol
fluid outise that bathes the neuron
extracellular fluid
What are ions, and why are they important in neurons?
Electrically charged atoms or molecules.
Carry electrical charge across the neuronal membrane, playing a key role in neuronal signaling.
What is a polar molecule, and how does it relate to water?
A polar molecule has an uneven distribution of electrical charge. Water is a polar molecule because its oxygen atom has a net negative charge, while its hydrogen atoms have net positive charges.
What is an ionic bond?
An ionic bond is the electrical attraction between oppositely charged atoms or ions, such as sodium (Na+) and chloride (Cl-).
cations
Ions with a net positive charge
anions
ions with
a negative charge
What are spheres of hydration?
Spheres of hydration are clouds of water molecules that surround ions in solution, effectively insulating the ions from one another.
What is the phospholipid bilayer?
The structure of the neuronal membrane, consisting of hydrophilic “heads” that face the inner and outer environments and hydrophobic “tails” that face each other, forming a barrier betweem cytosol of the neuron and the extracellular fluid.
What is the structure of a protein?
Proteins are made of amino acids connected by peptide bonds, and they have primary, secondary, tertiary, and quaternary structures that define their function.
What is an ion channel?
Ion channels are membrane-spanning proteins that form pores through which ions can pass, allowing the movement of ions across the neuronal membrane.
What determines ion selectivity in channels?
Ion selectivity is determined by the size of the channel pore and the nature of the amino acid residues lining the pore, allowing only specific ions to pass.
What are ion pumps?
Ion pumps are membrane-spanning proteins that use ATP to transport ions across the membrane, maintaining the necessary concentration gradients for neuronal function.
Diffusion
Net movement of ions from regions of high concentration to regions of low concentration.
concentration gradient
The difference in ion concentration across the neuronal membrane, which drives the diffusion of ions.
What is electrical current?
The movement of electrical charge repersented by symbol (I)
What is electrical potential?
Electrical potential, or voltage, is the force exerted on charged particles due to a difference in electrical charge across the membrane. (V)
What is electrical conductance?
ability of charged particles to migrate across the membrane. (g) in Siemens
determined by the number of available ions and the ease of their movement.
What is electrical resistance?
Electrical resistance is the relative inability of charged particles to move across the membrane and is inversely related to conductance. (R) in ohms
Inverse of conductance so R=1/g
Ohm’s law
I=gV
Current = conductance x potential difference
if conductance is 0, the current is 0.
If voltage is 0, the current is 0
membrane potential
voltage across the neuronal membrane at any moment, represented by the symbol Vm.
