NP1D Flashcards
(true/false) Tighter control in the central nervous system is needed, particularly because of the need for impulse conduction
true
What are some resident cells that can function like macrophages?
the microglia
When eliminating the extracellular space and replacing it with a glia cell known as the:
astrocyte
What part of an astrocyte will you see in an H&E stained tissue section?
you will only see the nuclei of these cells, everything else being a pink tangle of cell processes of neurons, oligodendrocytes and astrocytes that is collectively known as neuropil
Metabolic support:
How are astrocytes in simultaneous communication with sources of nutrition and waste removal and the cells they serve?
Astrocytes form a syncytium with other astrocytes via gap junctions in their cytoplasmic processes
How do astrocytes balance their cytoplasmic osmolarity?
with that of plasma, so that there are no fluid shifts into or away from the CNS
What happens when plasma becomes hyperosmolar?
astrocytes generate small molecules known as idiogenic osmoles that increase cytoplasmic osmolarity and prevent fluid shifts into plasma
What can lymphocytes do as part of their immune surveillance function?
can push between cells
an excitatory neurotransmitter
Glutamate
GABA, an inhibitory neurotransmitter
gamma-aminobutyric acid
astrocytes terminate ________________ signaling
neurotransmitter
Glutamate and GABA are converted to glutamine by _________
astrocytes
the glutamine can be transported back into neurons, converted to glutamate and/or GABA which is then packaged into secretory vesicles at the ____________________.
axon terminus
(true/false) Astrocytes posses receptors to most neurotransmitters, attesting to their central role in supporting signal transduction
true
Astrocytes also reverse the extracellular electrolyte imbalance which result from neuronal membrane ________________
repolarization
Neuronal membrane repolarization releases high levels of ______ into the extracellular space. Regions of high extracelular _____ induce electrical currents within astrocytes, the effect being that ____ is transported away from its site of release
K+
(true/false) There are resident fibroblasts deep within the CNS
False
Fibroblast are restricted to the_____________ and adjacent to large penetrating blood vessels
meningeal
What do astrocytes do in response to tissue injury?
Astrocytes will strengthen and extend their cytoplasmic processes by increasing synthesis of cytoskeletal intermediate filaments
These cells are of mesodermal origin whereas everyone else in the nervous system is of neuriectoderal origin
Microglia
Are like monocytes and resident macrophages elsewhere in the body
microglia
the delicate branches of microglia blend with the ________. these branches have sensors for signals that something is wrong in the enviroment.
neuropil
These are molecules thatare released only when there is tissue damage. A prominent example is cellular heat shock proteins. Heat shock proteins normally function within the cell, supporting protein homeostasis. But when released from cells, they are viewed as a danger signal. They bind Toll-like receptors on microglia, causing microglial activation and an inflammmatory response.
Damage Associated Molecular Pattern (DAMPs)
These molecules are specific to microorganisms, such as lipopolysaccharide (LPS) that is found in the outer membrane of Gram negative bacteria. LPS binds the same Toll-like receptors of microglia that are triggered by heat shock proteins.
Pathogen Associated Molecular Patterns (PAMPs)
Is produced by monocytes and lymphocytes when activated. If _____________is in the enviroment, microglia respond in turn by becoming activated to address - whatever the heck is going on. It’s an amplifier effect.
interferon
Tell me about activated microglia
- lose the branches, migrate to the source of the problem
- become phagocytic
- become active participant in the inflammatory response
- produce nitric oxide and interferons that promotes the activity of any incoming immune cells
- become active antigen presenting cells, supporting both cell mediated (MHC-I) and humoral (MHC-II) immune responses
Contains a lot of fat and fat is hard to digest - __________
CNS
Microglia are removing myelin, or dead neurons with their tremendous membrane surface area, they become _________
engorged
In tissue sections, engorged microglia have the appearance of macrophages with expanded foamy cytoplasm. This are known as ___________
glitter cells
What can be a powerful clue that something is wrong?
recognition of microglial activation and particularly gitter cell formation
If we encountered a disease of the astrocytes, which processes would be affected?
neuronal signal transduction
myelin formation by oligodendrocytes
tissue water balance in the CNS
