Electrophysiology Of Neurons Flashcards
What is electrical potential?
Separation of charges on each side of the cell membrane
What is the current
The flow of charged particles
What does the resting potential membrane on an axon have for the distribution of electrolytes
It has an unequal distribution of electrolytes with some on the inside and some on the outside
In a resting potential membrane, what electrolytes does the intracellular fluid have and what electrolytes does the extracellular fluid have?
The intracellular fluid has high potassium
The extracellular fluid has high sodium
What is the action potential begin with
Stimulation of a neuron, specifically the dendrites
After the dendrites are stimulated what happens
Depolarization occurs where ions trade places
After depolarization what happens?
The voltage must reach a critical level called the threshold which is measured in millivolts
After the threshold is reached, what happens?
The neuron produces an action potential meaning it fires
After the neuron fires what happens
What the original segment repolarizes?
What is the refractory period and give two reasons why it happens
With a neuron cannot fire because
It’s already in action potential
It has just completed depolarization
Saltatory versus continuous conduction which is faster and why?
Saltatory is faster because
It fires with greater strength
It depolarizes fewer times
What are presynaptic and postsynaptic neurons?
A presynaptic neuron is the neuron before the synapse space
A postsynaptic neuron is the neuron after the synaptic space
How many synapses can a neuron have
Hundreds of thousands
What is a synaptic cleft?
The gap between two neurons
What is a chemical synapses?
Any synapse that requires the use of neurotransmitters?
There are over 100 neurotransmitters
Four characteristics of neurotransmitters
The chemical must be produced by a presynaptic neuron
It must be released in response to stimulation
It must bind to receptors on the postsynaptic cell
And must alter the physiology( function) of the postsynaptic cell
What is the small molecule neurotransmitter acetylcholine made of?
And what is the synapse called that uses it
Is made acetic acid plus choline
Any synapse that uses ACH equals cholinergic synapse
And small molecule neurotransmitters what are biogenic amines?
5 examples
They are made with nh2( the amine group)
Epinephrine and norepinephrine, released during fight or flight, together the equal adrenaline
Histamine equals allergic reaction such as watery eyes
Dopamine equals creating pleasure in the brain
Serotonin equals responsible for your mood and getting you to sleep
What are small molecule neurotransmitters that are amino acids?
Glutamate 50% of your brain’s neurons use this
Glycine
Gamma aminobutyric acid ( gaba)
Inhibitory meaning slows things down
What are small molecule? Neurotransmitters nitric oxide function
Nitric oxide or no is excitatory in the brain, spinal cord and the penis
It’s a vasodilator( what’s in Viagra)
What is the small molecule neurotransmitter Co function
It’s carbon monoxide
In your body it’s excitatory
Insulin release is stimulated by this
It’s anti-inflammatory
It constricts blood vessels
What small molecule? Neurotransmitters function are neuropeptides
They are composed of they are composed of 3 to to 40 amino acids
Endorphins your body’s natural pain reliever
Exercise releases, ease as does sex
Neuropeptides are linked to learning sex drive and mental illness
They are 200 times stronger than working
What are the three ways to remove neurotransmitters and why do you need to do it
They are left over when you stop a movement
Diffusion, moves from the synaptic cleft
Dissolved by astrocytes
Reuptake, neurotransmitter is taken back and recycled by the cell that released it
Degradation, acetylcholinesterase (aChase) breaks down ACH while it is still in the synaptic cleft
What is required for damaged neurons in the pns to regenerate
The Soma and a portion of the neurolemma need to still be intact
What is a neurolemma?
The outside wrapping with the organelles on the outside last wrap of the myelin sheath
What is the role of macrophages in the repair in the PNS
Macrophages remove debris of the damaged neuron and its myelin sheath
What is the regeneration tube?
The portion of the neurolemma that remains intact
And axon stump will put out several branches until one of them finds their way into the tube and the other branches will degenerate
The tube will guide the growth until the branch reaches its Target cell
Can damage cells in the CNS regenerate
No, they cannot
