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the brain is made up many different cells the most important these is
the nerve cell this is because nerve cells are responsible for the processing of
information
Neurones have three important components dendrites
which are processes that conduct signals from sensory receptors
or other neurons to the cell body. The cell body
also known as the soma which is where the nucleus
and other organelles required to synthesize the proteins which make up
nerve cell
reside and axons which are processes that send
action potentials away from the cell body to other neurons or to other cells
such as muscles or glands the properties of a neurone
are all determined by its membrane this because the membrane of a neurone maintains a
charge across it
the member of a neurone is made up a bilayer of fat
which insulates and prevents charged ions moving through it freely
but dotted in the membrane are ion channels
which do allow movement of ions by controlling the opening/closing of
specific ion channels a relative different in charge
can be established across the membrane. The two most important
ions in this process are sodium Na+
and potassium K+ the cell membrane
is dotted with sodium potassium ATPases which actively pump three sodium ions
out for two potassium ions in
also inside cell
are large negative anions which cannot diffuse across the membrane
despite sodium being pumped out potassium being pumped in
some ions diffuse back across the membrane. eventually
all these factors balance out the membrane maintained a stable
equilibrium with the inside the cell negative relative to the outside
this is known as the resting potential and is usually
about minus seventy millivolts. An important part of a neurons information processing
capacity
is its ability to spike. when a nerve cell is stimulated
the stimulus will cause a rise in the charge inside the cell
inside the cell membrane are voltage-gated sodium channels
and if men in potential to sell reaches a certain value
known as the threshold voltage sadly many of the sodium ion channels become
open
so deep that puts down its concentration gradient
and its electrochemical gradient into the cell this leads to the inside the
cell becoming progressively more positively charged
as becomes more positively charged more and more false gated sodium channels
open
and purses a positive feedback continues into all the while skating channels are
open
after reaching a peak the cell becomes much less negative
this thing cause the voltage-gated stone pine channels to close
potassium channels to open sodium can no longer and the cell
millions be pumped up by the sodium potassium ATPs
potassium channels now open an apt asking to fly freely
this means the positive charge inside the cell then begins to fall again
some other potassium channels Open junior action potential
a slow to close missile advertising to keep flowing out of the cell
down its concentration gradient means up briefly becomes even more negative than
it was last resting
during this time many the ion channels are inactivated
and neon cannot fire again this is known as a fractured period
eventually the cell reaches stable equilibrium again
and the membrane is restored his resting voltage when an action potential because
its section membrane
Sony inflows in and the inside the cell that point because more positive
to these positive ions diffuse sideways mysteries in action potential
and Jason section the memory
this allows the ashford
will to propagate along the axle until it reaches an axe on terminal
at the end of the axle the action potential reach the signs
here there's a brief gap between the action won't sell dendrite another
this is known as the sign up tick left when the action potential reaches the
end up a sign ups
it reiterated chemicals could near transmitters there also a lecturer
senators
which won't talk about now these chemicals then diffuse across the
synaptic cleft
bind to receptors on the postsynaptic neuron the binding
these receptors modulates the time channels opening to closing them
and altering the flow lines through them
dismay excite the next year going positive ions deployment
moving the membrane voltage close to the threshold voltage possibly trigger an
action potential
or im inhibit an eqn bosnian plucks
negative ions such as chloride moving the membrane voltage
further away from specialty
in conclusion neurones the primary information processing sup the brain
much other information processing capacity is to use the alteration
voltage
across the membrane at rest the inside the cell is maintained at a slightly
negative voltage
due to the action sodium potassium pump
but if the voltage inside the cell rises above a threshold value
an action potential trade this propagate along in your own
to the rich is a sign ups richard is reason your judgment is
which diffuse across the synaptic cleft by interceptors in the post an afternoon
causing the process to repeat