2_Neuroanatomy & Neurophysiology @ Cellular Level Flashcards
Neuron Doctrine
neurons are the basic signaling unit of the nervous system
Principle of Dynamic Polarization
signals flow in a predictable and consistent direction
Principle of Connectional Specificity
no direct cytoplasmic connectivity between neurons and the connections formed between neurons are specific (not random)
What are the two locations where gap junctions are sometimes located?
between dendrites in certain systems and between neurons and glial cells in other instances
What is one possible function of gap junctions?
The storage of extracellular calcium necessary for release of neurotransmitters
A neuron has a receptive area for _______; _______ and ________
localize input; dendrites and cell body
A neuron has a integrative area for _______; _______
triggering a response; axon hillock
A neuron has a conductive area for _______; _______
carrying a signal; axon
A neuron has a output area for _______; _______
secretory; axonal terminals
What are the various ways in which a neuron can be classified?
by size, number of processes, directions they project (but all have these regions in common
When 1 postganglionic neuron receives synaptic input from several preganglionic neurons, this type of connectivity is called _____?
convergent
When 1 preganglionic axon can form synapses on several postganglionic neurons, this type of connectivity is called ____?
Divergent
What type of cell can be supportive as well as reparative?
Astrocytes
In the CNS which cells are responsible for myelination of axons?
Oligodendrocytes
In the PNS which cells are responsible for myelination?
Schwann cells
What is the roll of microglia in the CNS
To function as macrophages
How many postganglionic neurons can a single preganglionic neuron synapse with?
multiple
Does the sympathetic or parasympathetic nervous system exhibit a greater degree of divergence?
sympathetic
What is the function of channels?
To selectively allow the flux of ions into or out of the neuron.
Non-gate channels ________________?
allow for diffusion of small ions
What are the three types of gated ion channels?
modality, ligand and voltage
Define a modality gated ion channel
A channel in which each receptor is sensory modality specific
Name two types of ligand (binding to the receptor) channels
ionotropic and metabotropic
What is the function of voltage gated-ion channels?
change the membrane potential
When the change in membrane polarity is graded and decays away from site of initiation (syanpse in the CNS, receptor in PNS), it is what kind of potential?
Electrotonic
A change in membrane potential along the axon of a neuron; requires the presence of voltage gate channels (only located on the axon of a neuron) is a _________ potential.
action
EPSP cause electrical activity or membrane polarity to become more ______ w/ respect to resting membrane potential.
positive
IPSP cause electrical activity or membrane polarity to become more ______ w/ respect to resting membrane potential
negative
The all or none response implies that there is _________________________________?
no decay in the amplitude or speed of an action potential once it has been generated.
What is the ultimate end of the action potential?
To generate the release of a neuroactive substance at its terminal end.
In the normal functioning system (an AP) is ______________, traveling from the axon hillock to all of the ___________________________
unidirectional
axon terminals of each neuron.
Transmitter release is always a response to what?
An action potential.
What does the amount of the transmitter released depend upon?
The frequency of action potentials traveling down the axon.
Can the amount of the transmitter being released be modified along the axon?
NO, it can only be modified at the terminal end.
What are two types of non-associative learning (temporary)?
sensitization and habituation
What are two types of associative learning (long lasting)?
long-term potentiation and long-term depression
When is LTP best modulated?
In explicit learning (facts)
What is LTP?
A sustained increase in synaptic strength elicited by brief, high-frequency stimulation of excitatory afferents.
axodendritic:
communication between an axon of one neuron (facilitory/ excitatory)
axospinous:
more complex type of axodendritic (more complex b/c of the learning nature of spine).
axosomatic:
communication between axon and cell body (inhibitory)
axosynaptic:
axon terminal ends at another terminal
dendrodendritic:
communication between dendrite of one cell to a dendrite of another.
axoextracellular:
Axon terminals that have no specific target but instead secrete their transmitter chemicals non-specifically into the extracellular fluid
axosecretary:
an axon terminal synapses with a tiny blood vessel called a capillary and secretes its transmitter directly into the blood
axoaxonic:
communication between the axon of one neuron and the axon of another neuron. (excitatory)
