Electrophysiology Flashcards
How did we find out that animals use electricity to control muscle
By electrocuting a frog. by Luigi Galvani
What has a massive concentration gradient out of the cell
K+
What has a massive concentration gradient into the cell
Na+
What supplies the energy for the sodium potassium concentration gradient
ATP
How many Na+ goes out per ATP
3 molecules
How many K+ goes in per ATP
2 molecules
What happens the more the pump occurs
The intracellular fluid becomes negatively charges and vice versa
What is the diffusion of ions determined by
Membrane permeability, concentration gradient, voltage gradient
What ions can go in easier than the other type
cations
What is a K+ leak channel
Lose the potassium
Is the membrane more permeable to K+ or Na+
K+
What also contributes to the -ve charge (NOT ATP)
Proteins
What is a leak channel
Always open, always leak a specific chemical
What is a ligand gated channel
Open or shut by a specific chemical messenger
What is a voltage gated channel
Open or shut by voltage
What is depolarisation
Make the cell less charged by adding Na+ to the cell
What is hyperpolarisation
Makes the cell more charged by removing K+ to the cell
What cells has the ability to amplify
Nerves and muscles
Why can they amplify polarisation
Because they have voltage gates
What is the action potential
Electrical excitability which is done via voltage gates
What happens at the start of depolarisation
Ligand gates which initially depolarise the cell
What happens after the ligand gates initially depolarise
The voltage gates open, letting sodium in
What happens after the voltage gates open
they lock for a few seconds then close
What happens with K+ channels
They do not lock, they only close
Which channel is faster (Na+ or K+)
Na+
What happens first
the Na+ comes in first then the K+ comes out
What happens when the K+ channels open
Repolarisation
How do we get the Na+ out and the K+ in after repolarisation
Through the Na+ K+ pump
What is the absolute refractory period
When the Na+ channel is locked
What is the difference between locked and closed (in this context)
locked = no input can open it, closed = a certain threshld can open it
What is the relative refractory period
Where higher stimulus is required
Are there varying sizes of action potentials
No
What is the difference between strong and weak stimulus
Strong stimulus has a higher quantity of signals than weak ones
What happens when one part is depolarised
It spreads through propogation
How quickly does the nerves move without myelin
2m/s
How do neurons speed up
through insulated myelin sheaths which jumps through the insulated schwann cells
What makes this speed up
Jumping
What is ogliodenedrites
central nervous system schwann cells
