Neuronal Physiology Flashcards
What are excitable Tissues
Tissues that produce electrical signals by drastically altering their resting membrane potential briefly
Depolarization
decrease in potential; membrane less negative
Repolarization
return to resting potential after depolarization
Hyperpolarization
increase in potential; membrane more negative
What affects the strength and length of graded potentials?
Stimulus strength
What affects the degree to which a graded potential will spread? Do they spread far?
Resistance, they do not spread far
What are some features of action potentials?
Self-propagating, Nondecremental, may be initiated by graded potentials
Do Sodium and Potassium pumps maintain the concentration gradient?
Yes
What happens once AP is initiated at the Axon Hillock
It travels down the Axon away from the cell body
How can action potential travel ?
Contiguous Conduction, Continuous movement, Saltatory Conduction, AP jumps along Axon because of myelin
What occurs during contiguous conduction?
it is the second way of nerve impulse transmission
Where does contiguous conduction occur?
Unmylinated axons
How is it possible for AP to form on the axon?
Due to the opening of sodium and potassium channels
Do graded potentials spread passively?
Yes
What is saltatory conduction
an electrical impulse skips from node to node down the full length of an axon, speeding the arrival of the impulse
Synapse
the junction of two neurons, the junction between a neuron and a target cell
Excitatory Post-Synaptic Potentials
synaptic inputs that depolarize the postsynaptic cell, bringing the membrane potential closer to threshold and closer to firing an action potential.
How are Excitatory Post-Synaptic Potentials produced
by opening Na+ and K+ channels, similar to the nicotinic ACh receptor.
Inhibitory Post-Synaptic Potentials
temporary hyperpolarization of postsynaptic membrane caused by the flow of negatively charged ions into the postsynaptic cell
When is a IPSP received
When an inhibitory presynaptic cell, connected to the dendrite, fires an action potential.
Grand postsynaptic potential
the total potential in the postsynaptic neurons.
Temporal Summation
the summation in the nervous system in which a single presynaptic neuron involves in the production of multiple subthresholds over a period of time.
spatial summation
sensory summation that involves stimulation of several spatially separated neurons at the same time.
presynaptic inhibition
an inhibitory neuron provides synaptic input to the axon of another neuron (axo-axonal synapse) to make it less likely to fire an action potential.
Convergence vs divergence
Divergence allows one neuron to communicate with many other neurons in a network. Convergence allows a neuron to receive input from many neurons in a network
