Nerve And Muscle Flashcards
What is an afferent nerve?
Transmits information from the body to the CNS
What is an efferent nerve?
Transmits commands from CNS to all areas of the body
What does the autonomic system relate to?
Supplies the internal organs
Involuntary issues- has both parasympathetic and sympathetic functions
What direction does an impulse travel along a neuron?
From dendrites towards axon terminals
In the phospholipid bilayer which is hydrophobic and which is hydrophillic?
Tails are phobic, heads are phillic
What is depolarisation?
Polarity inside the cell becoming more positive
What is hyperpolarisation?
Polarity in the cell becoming more negative
what is potassium diffusion potential?
K+ diffuses down the concentration gradient via leaky channels, as positive charges leave the cell becomes more negative compared to outside causing some K+ to diffuse back, eventually hits equilibrium where inflow=outflow
Sodium potassium pump
Electrogenic pump
Pumps 3 Na+ ions out in exchange for 2K+, inside of cell loses 1+ ion maintaining negative potential inside
What happens inside a resting cell?
Potassium leak channels open- diffusing down the conc gradient
Voltage-gated sodium channels closed- no free movement of sodium across the membrane
Sodium-potassium pump working- effective loss of +ve charges from inside the cell
What is the resting membrane potential?
Electric potential that exists across the cell membrane in the resting cell, normally around -70mV
What is an action potential?
All or nothing events
Process of neuronal signal transmission, rapid changes to membrane potential allowing electricity to flow along the neurons
What is an action potential stimulated by?
Depolarisation of the cell which leads to the opening of voltage gated sodium ion channels, depolarising the cell further, when membrane potential hits -55mV permeability increases as more sodium channels open.
What is the threshold potential of an action potential
-55mV! If not hit the action potential can’t go through
What is the absolute refractory period?
Voltage gated sodium channels will not respond to any amount of stimulus so no action potentials possible.