Neuro 2 Flashcards
fast axonal transport
membrane bound proteins and organelles
anterograde fast axonal transport
cell body to axon terminal; up to 400 mm/day
retrograde fast axonal transport
axon terminal to cell body; 200 mm/day
slow axonal transport
cytoplasmic proteins (enzymes) and cytoskeleton proteins -slow due to frequent periods of pausing movement
anterograde slow axonal transport
up to 8mm/day
motor proteins for fast axonal transport
kinesins and dyneins
kinesins
anterograde transport
dyneins
retrograde transport
motor proteins for fast axonal transport are driven by…
ATP hydrolysis
synapses
chemical or electrical (majority chemical)
What is contained in synapses?
extracellular matrix (proteins and carbs) that hold pre and post synaptic cells
how do billions of neurons find correct targets during development?
depends of chemical signals
growth cones
sense and move towards particular chemical signals
glia
provide support for neurons
glial cells found in CNS
ependymal cells, astrocytes, microglia, oligodendrocytes
glia cells found in PNS
schwann cells, satellite cells
myelin forming glia
a substance composed of multiple concentric layers of phospholipid membrane wrapped around an axon that provides structural stability, acts as insulation around axon to speed up signals, and supply trophic (survival) factors
types of myelin forming glia cells
oligodendrocytes and schwann cells
myelin and oligodendrocytes
wrap the axons of multiple neurons (up to 50)
myelin and schwann cells
1 cell wraps a segment of 1 neuron
underlying mechanisms of MS
- autoiimune (immune cells attack myelin)
- reduce ability of myelin producing cells
- genetic and enviro factors
ganglia
bundles of cell bodies
satellite glial cells
form a supportive capsule around cell bodies and supply nutrients to ganglia in sensory and autonomic cells
astrocytes
highly branched glial cells in CNS believed to make up half of cells in brain
functions of astrocytes
- take up and release chemicals at synapses
- provide neurons with substrates for ATP production
- help maintain homeostasis in ECF
- surround vessels
- influence vascular dynamics
microglia
specialized immune cells that reside in the CNS that protects and preserve neuronal cells from pathogens and facilitate recovery from metabolic insults
ependymal cells
line fluid filled cavities in brain and spinal cord that help to circulate cerebral spinal fluid
-possibly a source of neural stem cells
When an axon (PNS) is cut, the section attached to the cell body….
continues to live
When an axon (PNS) is cut, the section distal to the cut…
begins to disintegrate
Schwann cells can create a tube to….
guide the regeneration of axons
