Nervous system Flashcards
Why is it impossible for axons to apply another saction potential when an axon is in its refractory period
This because they are already doing an action potential or they are locked so its not possible
Why is it possible for there to be action potential when a cell is in the relative refractory period
The cell is hyperpolarized so its gated channels are ready to be open however it needs a greater stimulus because weh cell is hyperpolarized, the voltage is further away from threshold
How do axons code for intensity
To increase the intensity we increase the number of action potentials within a certain time period.
How do nerves code for intensity
All the axons in nerves will have different thresholds and as the stimulus increases so does the frequency of any axons with low stimulus
Why does myelin increase action potential velocity
The cell membrane under the myelin will have mo voltage-gated channels because they wouldn’t be able to access the ICF so the axon doesn’t have to use as many voltage gates so the action potential is able to jump from node of Ranvier to node of Ranvier
What are the options for the postsynaptic cell in a synapse
Neuron, gland, or muscle
What is a synaptic vesicle
It is a piece of cell membrane within the axon terminal of the neuron that is filled with neurotransmitters
What causes more sodium to come in than potassium leaving the postsynaptic cell
The inside of the cell is negative so more of it comes
How do we hit a threshold
We use a positive feedback loop of allowing more sodium to come into the cell until we hit the threshold
What are the options for neurotransmitters after the action potential has been transferred
There is reuptake into the presynaptic cell, enzymes will break down the neurotransmitter, or they diffuse away from the synapse
What is an excitatory synapse
This is when an action potential is used to start action potential in a postsynaptic cell
What is an inhibitory synapse
This type of synapse is when an action potential is inhibited in the postsynaptic cell. Often this will cause potassium to leave the cell through certain channels or channels open that let chloride ions in. This is so that the cell potential can become more negative to prevent action potential from happening.
