Neurophysiology Flashcards
During it’s resting potential, the neuron is negative charged at ______
- 70mv
An electrically charged atom, or particle that has lost or gained an electron (which gives it a positive or negative charge) is called an
Ion
The inside of the neuron has
potassium ions
The outside of the neuron has
sodium ions
Embedded in the neuron membrane are a number of _________ that act as _________
specialised protein molecules, ion channels
What is meant by diffusion forces (gradient)?
high concentration of ions are attracted to areas of low concentration or vice versa.
What is meant by electrostatic forces (gradient)?
Positively charged ions are attracted to negative ones and vice versa.
What is the function of the sodium-potassium pump?
maintain the intra and extra cellular balance of ions by a complex protein molecule located in the membrane.
the sodium potassium pump forces out 3 sodium ions for every ______ it takes in.
2 potassium ions
The sodium potassium pump forces out _______ for every 2 potassium ions it takes in.
3 sodium ions.
What causes an action potential?
A sudden movement of sodium and potassium ions (+30mV)
What is the threshold potential?
Triggering event is when resting potential becomes more positive by about +15mV
Excitatory postsynaptic potential (EPSP) is when___
stimulation causes the voltage inside the cell to become more positive.
Inhibitory postsynaptic potential (IPSP) is when ____
the cell becomes more negative.
A neuron fires, or it doesn’t, this is called the
all-or-nothing principle
A neuron cannot fire again during the ______ period
refractory
When the neuron drops below -70mV after an action potential it is called?
refractory period
Stimulation of the axonal receptors causing less neurotransmitters to be released by the presynaptic neuron is called?
presynaptic inhibition
all neurotransmitters in the CNS are associated with ion channels in one of two ways:
- ionotropic recepetors 2. metabotropic receptors
When the receptor and ion channel form part of the same molecular unit it is called?
ionotropic receptors
When the receptor and ion channels are separate entities they are called?
metabotropic receptors.
Which cell is 10 times more common than brain neurone?
Glial cells
A glial cell is ____ the size of a neuron.
one-tenth
the Oligodendrocyte is a type of ____ cell.
Glial
What is the function of the Oligondendrocyte?
it provides the myelin that covers the axons of most nerve fibres in the brain and spinal chord.
In the peripheral nervous system, myelin is produced by the?
Schwann cell
A function of the glial cell astrocyte is to?
provide a covering to the blood vessels of the brain which forms the blood-brain barrier
What bars the entry of most larger molecules and toxins?
the blood-brain barrier
Na+ stands for?
sodium
K+ stands for?
potassium
The movement of an action potential along the axon is called?
Nerve impulse
Stimulation producing 2 EPSPs in quick succession illustrates?
temporal summation
What are two characteristics of the postsynaptic membrane?
Thickened appearance and receptor proteins
A key event in the release of neurotransmitter molecules into the synaptic cleft is the
influx of Ca++ions in response to the arrival of an action potential at the button or bouton.
Neurotransmitters are produced in the
soma and synaptic terminals
Dopamine, Serotonin and Norephinephrine are
Amine’s
Sympathetic neurons are
cholinergic and adrenergic
Parasympathetic neurons are
cholinergic
What is the function of GABA?
decreases the firing of cells
A chemical in the postsynaptic cell that is activated by a G protein (after receptor stimulation) is called?
A second messenger
Neurotransmitters are secreted from _________ in response to the arrival of an action potential.
axon terminal
The process by which similarly charged particles repel each other and are thus distributed throughout a medium is termed?
electrostatic pressure
What restores the membrane potential from the peak of the action potential back to its resting level?
Potassium ions move out of the cell
Whenever the membrane potential reaches threshold what happens?
an action potential
What prevents cross talk between adjacent neurone?
Myelin
movement of the axon membrane potential from -70mV to -65mV is called?
depolarization
