Cytology Flashcards
cell classification
polarity
functional
polarity classifications
number of poles:
1: multipolar
2: bipolar
3: pseudo-unipolar
bi-polar
specialized- seen in sensory systems
smell, sight, vestibular
multi-polar
most common
predominant kind of neuron in CNS and PNS
pseudo-unipolar
evolves for speed/faster conduction- bypasses cell body so it doesn’t have to travel through
seen for pain/pressure
self propagating
golgi I
LONG axon which projects from one subsystem to another (brain–>SC, SC–>foot)
Golgi II
(interneurons)
SHORT axons
make connections with other neurons in the same subsystem
most numerous; short or no axon;
neurons that integrate things (connect dorsal horn to ventral horn of C5 on the same side)
1: segmental
2: propriospinal
segmental golgi II
project only to the same segment
associative: same side (ipsilateral fiber)
commissural: opposite side (contralateral fiber)
Propriospinal golgi II
project to other SC segments
tract cells
similar to golgi I but reside only in the CNS
forms tracts- collections of axons carrying the same kind of information (project to higher or lower levels of communication; fasiculus)
Functional classifications
1: directional
2: action on other neurons
3: discharge patterns
4: neurotransmitter release
directional classifications
afferent
efferent
interneurons
point of reference is usually the CNS; when it is, then you can refer to them as sensory or motor neurons
afferent=
coming to the point of reference (CNS)
usually “sensory”
efferent=
leaves the point of reference (CNS)
usually “motor” in the sense that it innervates muscles
actions on other neurons
excitatory:
inhibitory:
modulatory:
modulatory=
changes how the system reacts to the next time the stimulus is introduced
endorphins- modulate system to feel less pain to same painful stimulus
discharge patterns
tonic or regular spiking
phasic or bursting
fast spiking
thin spike
tonic (or regular spiking) discharge pattern
firing- always firing at a rhythmic rate and changed by increasing or decreasing firing rate; slow adapting
stimulate a neuron, continue to fire for a long time
phasic (or bursting) discharge pattern
“dynamic”
only on when they are stimulated and go off quickly; quick adapting
stimulate a neuron, fires, stops when stimulus is removed
fast spiking discharge pattern
fast firing rates
neurotransmitter release
cholinergic neurons
GABAergic neurons
glutamatergic neurons
dopaminergic neurons
serotonin
cholinergic neurons
excitatory to muscle
inhibitory to PNS
acetylcholine- usually always excitatory, used to contract muscle and inhibit the heart
GABAergic neurons
primary inhibitors
glutamatergic neurons
excitatory