Cytology Flashcards
Which system is associated with decreases in reflexes?
PNS (hyporeflexia)
What system is associated with increases in reflexes?
CNS (hyperreflexia)
which nerve cell is excitable?
neurons
which nerve cells are non-excitable?
glial cells
function of an axon?
Action potential is propagated down it
function of the axon hilock?
contains a high density of gated sodium channels, where AP is generated
what is average range of axon diameter?
.2 micons to 20 micros
Describe the neural doctrine
each neuron is a distinct cell whose processes begin at cell body. no continuity
describe the principle of dynamic polarization
information flows in a precise and consistent direction
Describe principle of connection specificity?
no cytoplasmic continuity, only connect to specific things, precise and specialized contacts
what are the three different shapes of a neuron?
unipolar: one neurite, bipolar: two neurites, multipolar: more than two
three functional classifications of neurons?
Afferent, efferent, interneurons
7 functions of glial cells?
provides firmness, myelin, remove debree, buffer ions, guide neurons to terminal sites, blood brain barrier, shuttle particles from blood to nerves
function of microglia?
mobilized after injury, infection or disease. small enough to cross the blood brain barrier
what are the three types of macroglia?
oligondendrocytes, schwan cells, astrocytes
function of oligodendrocytes?
provide myelin to CNS
function of schwann cells?
provide myelin in PNS
function of astrocytes?
Complete all of the function of glial cells
T/F glial cells replace neurons that have died
True
which direction does fast anterograde transport move?
from cell body to axon terminal
which direction does slow anterograde move?
from cell body to axon terminal
which direction does fast retrograde axoplasmic transport move?
from axon terminal to cell body
Does fast anterograde transport require energy?
yes
motor proteins needed for fast anterograde?
kinesin
rate of transport with fast anterograde?
400- 1000 mm/day
what elements are transported by slow axonal transport?
cytoskeletal elements (proteins used for fibrillar elements) and soluble proteins (neurofilaments and microtubules)
rate of transport with slow axonal transport?
.2-3 mm/day
does the slow axonal transport require energy?
no
which transport systems require the use of microtubles?
fast anterograde and retrograde
Does fast retrograde require energy?
yes
molecule needed for fast retrograde?
dynein
function of fast anterograde?
vescicles carry aged organelles to the cell body for repair or degradation
somatic efferent neurons are classified as…?
multipolar cells
which functional type of neuron is prevalent in the nervous system?
interneurons