4. Brain Mechanisms And Behaviours III Flashcards
(34 cards)
A message moves through a neuron by
Action potentials
What is the charge of the inside of a neuron
The intracellular fluid is NEGATIVELY charged
What is the charge of the outside of a neuron
POSITIVELY Charged
What ions are found inside the neuron
A- and K+ (organic ions/proteins and potassium ions)
Molecules of high concentration tend to move to areas of low concentration
Diffusion
What is electrostatic pressure
Same charges repel, opposite charges attract
a high concentration of potassium on the inside and low concentration on the outside means
Potassium ions will move from the inside of the cell to the outside; however because the inside of the cell is negative and potassium is positive the potassium stays attracted to the inside, hence it stays in
Why do the organic amines A- stay in even though there is low concentration of them outside the cell and they are being repelled by the negative inside
Because the amine molecules are too big
What ions are on the outside of a neuron cell
Na+ sodium ions
Cl- Chloride ions
Cl- is on the outside and due to the force of diffusion they are
Pushed into the cell because there is a low concentration of Cl- ions on the inside, however the electrostatic pressure pushes most of them back out because opposite charges repel (neg inside and neg chloride) and positive charges attract (positive outside and negative chloride.
How come sodium’s get pushed in
Because they are + so due to electrostatic pressure the negative inside attracts them, and because due to the force of diffusion Na+ will go from an area of high concentration (outside) to low conc (inside).
Not all of them tho most go in then get pushed back out because of the sodium potassium pump/transporter situated in the cell membrane.
For every 2 potassium’s sent into the cell from the outside through the pump, the pump will push out
3 sodium ions
So basically the pump is there to maintain
Equilibrium/ negativity on the inside and positivity on the outside
When there is no communication between neurons and they are working non their ion pumping/diffusion this is called the
Resting potential
The electrical charge on the membrane is called the
Membrane potential
The term potential refers to all the stored up source of energy and in the neuron cell this energy is
Electrical energy
The difference between charges on the outside and inside yields
Potential which is again a stored up source of nrg, specifically electrical nrg for the neuron cell
If we want to reduce membrane potential (depolarization)= reduce energy= reduce the exchange of charges then we
Reduce the difference between the outside and the inside charges by inserting positively charged ions inside the axon leading to depolarization
The difference between the inside and outside is __ milli volts
-70
Is we add positive charge on the inside (depolarization) the new difference is reduced and now less negative meaning the less
The difference between the outside and inside of the neuron cell, this way we reduce the membrane potential.
If we add enough positive charge to the inside of the neuron (stimulus applied) it will eventually stop going back down to -70 and start moving up toward action potential. This value from reduction that we reached that would cause it to go high up is called the
Threshold of excitation/ excitation point
The graph will go up to __ milli volts after excitation is reached
Almost +40
The whole process of neg becoming positive in the inside/the other way around is called action potential, its the way back down on the graph and it takes _ msec to complete
2
What stimulates the mechanism of action potential
When the pre synaptic neurotransmitter bind to the post synaptic cell and action potential goes through to the next cell