Neuro A & P at the Cellular Level

Question 1

what is a neuron

Answer 1

the basic signaling unit of the nervous system

Question 2

what is the Principle of Dynamic Polarization

Answer 2

signals flow in a predictable and consistent direction

Question 3

what is the Principle of Connectional Specificity

Answer 3

no direct cytoplasmic connectivity between neurons and the connections formed between neurons are specific (not random)

Question 4

where are gap junctions present in the CNS

-what is their potential function

Answer 4

between dendrites in certain systems and between neurons and glial cells in other instances
function
-storage of extracellular calcium necessary for release of neurotransmitters

Question 5

a generalized neuron has what components?

Answer 5

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

Question 6

common characteristics of a CNS neuron

Answer 6

dendrite (receptive area)
soma (also a receptive area)
axon hillock, initial segment (integrative area)
axon (conductive area)
terminals (synapse; secretory area)

Question 7

types of glial cells in the CNS

Answer 7

astrocytes
oligodendrocytes
microglia

Question 8

astrocyte

-functions

Answer 8

supportive

reparative

Question 9

oligodendrocytes

• function
• PNS counterpart

Answer 9

mechanism of myelination
PNS counterpart
-Schwann cells

Question 10

microglia function

Answer 10

macrophage of the CNS

Question 11

what are the layers of connective tissue over neurons?

Answer 11

mesoneurium
endoneurium
perineurium
epineurium

Question 12

what are the synaptic types that we care about?

Answer 12

axodendritic
-axospinous (more complex type of axodendritic synapse)
axosomatic
axoaxonic

Question 13

what are different ways we classify gated ion channels based on what activates them?

Answer 13

modality - each receptor is sensory modality specific
ligand - binding to receptor
-ionotropic
-metabotropic
voltage - changes in potential

Question 14

what is electrotonic potential

Answer 14

the change in membrane polarity is graded and decays away from site of initiation

Question 15

where is the site of initiation for a change in membrane polarity in

• CNS
• PNS

Answer 15

CNS
-synapse
PNS
-receptor

Question 16

excitatory postsynaptic potentials (EPSP)

• what is it?
• what type of event does it cause?

Answer 16

electrical activity or membrane polarity becomes more positive with respect to resting membrane potential
depolarizing event

Question 17

inhibitory postsynaptic potentials (IPSP)

• what is it?
• what type of event does it cause?

Answer 17

electrical activity or membrane polarity becomes more negative with respect to resting membrane potential
hyperpolarizing event

Question 18

receptor or generator potentials

• stimulus allows for…
• _____ in nature

Answer 18

stimulus allows for opening of channels

excitatory in nature

Question 19

what is an action potential

-requires the presence of…

Answer 19

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)

Question 20

action potential all or none response

Answer 20

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

Question 21

transmitter release

• always response to…
• amount released depends on…
• where can the amount released by modified?

Answer 21

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

Question 22

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

Answer 22

temporary
-non-associative learning
-sensitization/habituation
long lasting
-associative learning
-long-term potentiation/depression