Flashcards in DLA 27 +DLA 28 Deck (19)
What is the BBB?
Protects the CNS from imbalances in surrounding
environment- electrolytes, hormones, metabolites
complex tight junction, continuous basal lamina
surrounded by foot processes of astrocytes
can lose effectiveness during certain diseases
some parts have no barrier (homeostatic reasons)
What is multiple sclerosis?
autoimmune disorder that targets myelins basic protein
What are the three stages of the demyelinating process?
1) Myelin breakdown associated with lymphocyte and macrophage infiltration of affected area- plaque
2) Proliferation of astrocytes – gradual infiltration of astrocytes intodemyelinating area
3)Reduced cellularity, astrocyte reduce in size
response to injury in CNS?
Absent/slow regeneration-blood brain barrier
• Ineffective phagocytosis
• Myelin debris persists
• Astrocyte scarring
response to injury in PNS?
• Macrophages migrate from blood
• Complete interruption of blood nerve barrier
Wallerian degeneration (anterograde)?
degeneration of axon distal to site of injury
PNS anterograde degeneration?
degeneration takes a few days
-Dedifferentiation of Schwann cells and alignment.\
CNS anterograde degeneration?
degeneration takes several weeks
-Loss of axon contact initiate apoptotic cell death
loss of Nissl substance from cell
• 1-2 days after injury
– Changes in cell body are
• amount of axoplasm lost
– large amount =CELL DEATH
damage to the schwann cells
Nerve fibers - Large,accumulation of
lymphocytes,,macrophages and,plasma cells
Ascending muscle,loss of muscle co–ordination &
The autonomic nervous system innervates what tissues?
1. smooth muscle
2. cardiac muscle
What are the two major divisions of the autonomic nervous system?
the sympathetic and parasympathetic
functions of the sympathetic nervous system?
fight, flight, or freight mode
function of the parasympathetic NS?
rest and digest mode
What are somatic motor neurons?
One long, heavily myelinated axon extending from the CNS to the effector
autonomic motor neurons?
Two Neuron System
•A lightly myelinated preganglionic neuron with the cell body in the CNS
•An unmyelinated postganglionic neuron with the cell body in autonomic ganglion in the PNS
Where are parasympathetic ganglia found?
near or in the walls of target organs
Where are the sympathatic ganglia found?
lateral to the spine
skull to the coccyx