Neurons - Resting Membrane Potential Flashcards
Examples of neurological disorders
Alzheimers, motoneuron, Parkinson’s, autism
2 types of communication by neurons
Electrical (dendrites, cell body, axon)
Chemical signals (synapses)
What’s resting membrane potential
Electrical potential difference across cell membrane if neuron when it’s not sending signals. Almost all cells in body have negative RMB
What’s excitable tissues
Tissue able to generate and propagate electrical signals. Neurons and muscle fibres posses this and can rapidly change RMB to respond to stimuli
How are intracellular potentials measured
- Microelectrode recording technique
- Path clamp technique
What generates RMP
electrical potential difference due to seperation of charge.
More negative charges inside cell compared to extracellular fluid
What caused charge difference (2)
Unequal concentration of Na+ and K+ resulting in electrochemical gradient
Unequal permeability
K+ and Na+ concentration in and out of cell
K+ more in cell and Na+ more out of cell. Concentration gradient is maintained by Na+/K+ pump (3 Na out 2 K in)
2 ion channels that have selective permeability
Non gated (leak) channels - open at rest allows diffusion of ions
Gated channels- voltage, ion, mechanically gated (closed at rest)
There’s more K channels than Na for leak channels what’s the ratio
At rest Pk/Pna = 40/1
What’s equilibrium potential
Nernst equation. Where electrical potential difference across cell where net movement of ions is 0
according to electrical gradient
What can’t use Nernst equation
Neurons that are permeable to more than one ion (leak channel for specific ion)
Glia cells have one leak channel so
RMP=Ek-80mV
Higher permeability shifts ion RMO towards what
It’s own equilibrium potential
Wha happens to RMP if you give a drug that activates K+ leak channels
RMP lowers so a bigger stimulus gap is created
