Membrane potential Flashcards
What is membrane potential?
Difference in electrical charge between inside/outside of cell
What is polarisation?
One side +ve one side -ve (-70, at rest is resting potential = sodium in extra cellular/ potassium in intracellular)
Ion channels?
Ions?
Special pores for passage of ions.
=ve /-ve charged particles (remove /add electron)
What is an atom?
Nucleus with protons and neutrons
What two processes change ion concentration?
Concentration gradient and electrostatic pressure (polarised cell membrane)
What is the difference between depolarise and hyperpolarise?
Depolarise - reduce polarisation of membrane eg goes down 70..65..63
Hyperpolarise - increases polarisation of membrane (70, 73, 77)
What does excitatory/ inhibitory postsynaptic potential do?
E- increases possibility of neuron firing as excites neurons, reaches threshold - action potential)
I - decreases PSP (takes away from threshold level)
What 3 things happen in PSP?
1) Graded response (intensity determines amplitude)
2) Instantaneous
3) decremental (less amplitude as travels along axon)
What is action potential?
The reversal of membrane potential from -70 mv to +30 - 50 mv, lasts 1 millisecond. Depends on EPSP being enough to male cell reach threshold.
What is threshold of excitation?
When membrane depolarised enough to create action potential generation (all or nothing response UNLIKE PSP WHICH ARE GRADED
What are two integration possibilities?
1) Spatial summation - simutaneous PSP sum to form greater PSP OR cancel eahc other out.
2) Temporal summation - PSP formed rapidly, as same synapse for greater potential (hyperpolarise as more accumulate, no time for resting potential)
What are most common axons?
Somatic and dendritic
What are directed and non directed synapses?
What is dendritic spine?
1) Release of neuro and site of neuro reception are close by
2) Opposite to 1
3) Nodules located on spine of dendrite.
How do small Neurotransmitters travel?
To golgi complex, packed into vesicles, go and cluster near presynaptic membrane , until exocytosis
Have effect on IONOTROPIC and METABO receptors. Involved in brief, effects on neuron. Released over directed synapse.
(Large (created on ribosomes) - golgi - microtubules - terminal buttons
What are receptors and ligands ?
1) Proteins on surface of PS membrane
2) Molecule that binds to another molecule