Neuro A & P at the Cellular Level Flashcards
what is a neuron
the basic signaling unit of the nervous system
what is the Principle of Dynamic Polarization
signals flow in a predictable and consistent direction
what is the Principle of Connectional Specificity
no direct cytoplasmic connectivity between neurons and the connections formed between neurons are specific (not random)
where are gap junctions present in the CNS
-what is their potential function
between dendrites in certain systems and between neurons and glial cells in other instances
function
-storage of extracellular calcium necessary for release of neurotransmitters
a generalized neuron has what components?
receptive areas (for localized input) -dendrites and cell body integrative area (for triggering a response) -axon hillock conductive area (carrying a signal) -axon output area (secretory) -axonal terminals
common characteristics of a CNS neuron
dendrite (receptive area) soma (also a receptive area) axon hillock, initial segment (integrative area) axon (conductive area) terminals (synapse; secretory area)
types of glial cells in the CNS
astrocytes
oligodendrocytes
microglia
astrocyte
-functions
supportive
reparative
oligodendrocytes
- function
- PNS counterpart
mechanism of myelination
PNS counterpart
-Schwann cells
microglia function
macrophage of the CNS
what are the layers of connective tissue over neurons?
mesoneurium
endoneurium
perineurium
epineurium
what are the synaptic types that we care about?
axodendritic
-axospinous (more complex type of axodendritic synapse)
axosomatic
axoaxonic
what are different ways we classify gated ion channels based on what activates them?
modality - each receptor is sensory modality specific ligand - binding to receptor -ionotropic -metabotropic voltage - changes in potential
what is electrotonic potential
the change in membrane polarity is graded and decays away from site of initiation
where is the site of initiation for a change in membrane polarity in
- CNS
- PNS
CNS
-synapse
PNS
-receptor
excitatory postsynaptic potentials (EPSP)
- what is it?
- what type of event does it cause?
electrical activity or membrane polarity becomes more positive with respect to resting membrane potential
depolarizing event
inhibitory postsynaptic potentials (IPSP)
- what is it?
- what type of event does it cause?
electrical activity or membrane polarity becomes more negative with respect to resting membrane potential
hyperpolarizing event
receptor or generator potentials
- stimulus allows for…
- _____ in nature
stimulus allows for opening of channels
excitatory in nature
what is an action potential
-requires the presence of…
change in membrane potential along the axon of a neuron
requires the presence of voltage gated channels (only located on the axon of a neuron)
action potential all or none response
there is no decay in the amplitude or speed of an action potential once it has been generated
ultimate end is to generate the release of a neuroactive substance at its terminal end
in the normal functioning system it is unidirectional, traveling from axon hillock to all of the axon terminals of each neuron
transmitter release
- always response to…
- amount released depends on…
- where can the amount released by modified?
response to an action potential
amount released depends on frequency of action potentials traveling down the axon
can be modified at the terminal end, not along the axon
learning types
- what do we call temporary learning and what are the two types?
- what do we call long lasting learning and what are the two types
temporary -non-associative learning -sensitization/habituation long lasting -associative learning -long-term potentiation/depression
