2. Cell excitability: resting membrane potential Flashcards
What is meant by an excitable cell?
A cell capable of generating an action potential at its membrane in response to depolarisation and may transmit an impulse along the membrane
What is a seizure?
A sudden burst of intense electrical activity in the brain.
What is hyperkalaemia?
High level of potassium
What are some causes of hyperkalaemia?
Acute kidney failure
Chronic kidney disease
Type 1 Diabetes
What are some symptoms of hyperkalaemia?
Weakness Paralysis Abnormal heart rhythms Nausea Muscle fatigue
What are some symptoms of hyperkalaemia?
Weakness Paralysis Abnormal heart rhythms Nausea Muscle fatigue
What is a resting membrane potential?
When a nerve fibre is not transmitting electrical signals
What is the nerve resting potential?
-70mV
What is a diffusion potential?
[CONC] inside > [CONC] outside Membrane is permeable to the cation Cation diffuses outwards - anions cannot flow as membrane impermeable Imbalance of charge across the membrane Potential difference Inside negative v outside
What is the equilibrium potential?
Voltage gradient oppposes further diffusion of cations
Difficult for cations to leave cell
Diffusion potential increases until EQUILIBRIUM state reached
Conc gradient = voltage gradient
What is Ek?
Conc gradient = to the voltage gradient
What is the Nernst equation?
be able to write this down MUST LEARN
know what each of the terms mean
What is a selective ion permeability?
****CHECK THIS*******
What is an electrogenic pump?
An ionic pump which maintains normal transmembrane conc gradients
What is the RMP of the K+ dffusion potential?
-90mV look at the underyling mechanisms
