Lecture 1 Flashcards
What are the two cell types that make up the nervous system?
1) neurons
2) glia
what is the main function of a neuron vs a glia cell?
neuron = signaling
glia = support
How many neurons are estimated to be in the brain?
100 billion
What are 4 main parts of a mammalian neuron?
1) cell body
2) axon
3) axon hillock/axon initial segment
4) dendrites/ dendritic spines
the shape and size of the neurons ____________________ are unique to different cells
projections
____________ receive info, while __________________ send info
dendrites receive
axons send
what is the signal integrator?
axon hillock
what provides insulation for neurons
myelin sheath
each neuron can form thousands of synapses with other neurons at _______________________ _________________.
dendritic spines
Dendritic spines are _______________
dynamic (can move)
Perikarya size is poor indication of ___________________
total cell volume
neurites occupy a greater percentage of cell surface area than the ______________.
soma
neurons only have one axon, but what is an exception to this?
Golgi cell of cerebellum
level of branching of dendrites is good indication of ___________________________________________ (___________________)
how many connections cells make (functionality)
are neurons cells?
YES
What are some components of a neuron that are commonly found in other cells?
- rough ER
- golgi complex
- lysosome
- smooth ER
- nucleolus
- microtubules
- mitochondria
-nucleus - ribosomes
_________________ always dictates function. What structure for this?
structure
cytoskeleton
neurotubules/neuronal microtubules are made of _____________________ and they associate with molecular motors for molecular transport of ______________, ______________, etc.
tubulin
synapses, mitochondria
____________________________ are almost always in axons and rare in _______________________.
neurofilaments (neuronal intermediate filaments)
dendrites
what form a meshwork in axons and bundles in cell body?
neurofilaments
actin microfilaments are super tiny and change shape when __________________. They are dynamic and form a network under membrane of ENTIRE neuron.
signaling
actin microfilaments are heavily concentrated in _______________________
dendritic spines
What are the 3 types of glia cells?
1) macroglia (astrocytes and oligodendrocytes)
2) microglia
3) ependymal cells
What are composed of a lot of lipids (aka myelin)?
oligodendrocytes
What provide myelination to neurons?
oligodendrocytes
what produce myelin in the central nervous system? They also create the nodes of ranvier.
oligodendrocytes
oligodendrocytes can produce many internodes of myeline and it wraps around about ____ times and how many are there in the optic nerve?
6
30-50
what are vulnerable to myelin related diseases?
oligodnedrocytes
OLIGDENDROCYTES:
FAST/SLOW mitotic rate and GOOD/POOR regeneration capacity (functional significance?)
Have many proteins which respond to ______________ —responsible for immune system destruction
*Can be selectively stained with antibodies against myelin producing/related proteins
slow, poor
B and T ccells
B and T cells
What are analogous to oligodendrocytes but in created in the peripheral nervous system?
Schwann Cells
schwann cells provide myeline for ______ internodes. cell body IS/ISN’T related to an internode.
one
IS
what is special about schwann cells?
they respond vigorously to injury
How do schwann cells respond vigorously to injury?
*Divide and migrate
*Phagocytose damaged myelin *Provide new myelination rapidly *Complete cutting of axon results in schwann cells forming tubes (bungner bands) that regenerating axons can grow into
what are bunger bands?
tells axons to reattach when severe injury occurs
astrocytes provide _____________________ for other CNS components.
structural support
astrocytes maintain the __________________________________
extracellular environment
what wrap around synapses and thought to “chemically” isolate synapses to prevent cells damage and excitation of neighboring synapses?
astrocytes
astrocytes can transport _______________ and ___________________________. They are also involved in the _____________ ______________ barrier. Also they maintain local ________ and __________ balances.
water and electrolytes
blood brain
pH and ionic
are astrocytes disease resistant?
yes
how can you tell that astrocytes are different from other cell types?
they wrap themselves around dendrites and synapses
______________________ need to be prevented from phagocytosis when it isn’t needed (like in Alzheimers_.
microglia
what is involved with Phagocytosis and inflammatory response
microglia
what is Mobile, active macrophage and Major player in inflicting immune system-mediated damage in CNS (important in autoimmune disorders)
microglia
why is microglia different from other glia?
microglia= mesodermal orgin
others= ectodermal
what is microglia selectively stained with?
Hortega silver carbonate
what cells line ventricles and spinal cord central canal?
ependymal cells
what are usually ciliated with normal microtubules and PRODUCE CEREBRAL SPINAL FLUID?
ependymal cells
ependymal cells form junction with neighboring cells with __________________ and gap junctions
desmosomes
