Nervous Tissue Flashcards
From where does the PNS and meninges derive from?
Neural Crest Cells
How does the CNS differ from the PNS?
CNS has:
- 4 types of glia
- Blood brain barrier
- No axonal basal lamina
PNS has:
- 2 Types of glia
- Weak BBB
- Axonal Basal Lamina
How are the CNS and PNS similar?
- Post mitotic neurons
- Invading cells
What are invading cells?
- Blood vessel endothelium
- Immune cells
What is the Nissle Body?
-The RER for the neuron
What protein is used for anterograde axonal transport?
Kinesin
What protein is used for fast retrograde axonal transport?
Dynein
What is contained within the arachnoid layer?
- Blood vessels
- Trabeculae
- CSF
What are the three layers of the cerebellar cortex?
- Molecular layer
- Purkinje Layer
- Granular layer
What is the intermediate filament of neurons?
neurofilament
What kind of intermediate filament will be found in satellite cells?
-Vimentin (Arise from neural crest cells)
What levels do the preganglionic sympathetic neurons arise from?
- T 1-12
- L 1-3
What levels do the preganglionic parasympathetic neurons arise from?
- CN III, VII, IX, X
- S 2-4
What is a euchromatic nucleus?
- Light staining areas of nucleas
- Indicate an active cell
Where do glia in the CNS arise from?
Neural tube
What is the intermediate filament of glia in the CNS?
- GFAP
- Gilial Fibrillary Acidic Protein
- Except Microglia!! (Vimentin)
Where do glia in the PNS arise from?
-Neural Crest
What is the intermediate filament of glia in the PNS?
-Vimentin
What are the types of glia in the PNS?
- Schwann Cells
- Satelite cells
What cells support neurons in the NS?
- Glia
- Endothelial cells
- Immune cells
What are the 3 CNS glial cells?
- Oligodendrocytes
- Astrocytes
- Ependymal cells
- Microglia (Non GFAP)
What do oligodendrocytes do?
- Mylenation
- One oligo insulates many neurons
- NO basal lamina
What do astrocytes do?
- Structural component of brain
- Forms part of blood brain barrier
- Repair (Scars)
- NT Pickup
- Most common tumor source
What do ependymal cells do?
- Circulates CSF
- No Basal Lamina
What is the most common tumor source in the CNS?
-Astrocytes
How do astrocytes act as the blood brain barrier?
-Feet on the capillary and feet on the neuron
What do microglia do?
-immune function
What intermediate filament is found in microglia?
-Vimentin
Where does the Dura, pia, and arachnoid develop from?
Neural Crest
What is the ratio of schwann cells to axons?
1 shwann cell : 1 axon : 1 internode
1 schwann cell per internode
How is the axon basal lamina continuous in the PNS?
-Schwann cells extend over nodes of ranvier
What is a schmidt-lanterman cleft?
Areas in the mylenation of axons where cytoplasm has percolated back into the layers of the membrane
What Surrounds axons in the PNS?
- Myeln
- Endoneurium
What surrounds fascicles in the PNS?
-Perineurium
What surrounds nerves in the PNS?
-Epinerurium
How are motor nerves repaired?
- Initial wallerian axonal degeneration
- Reorganization of proximal segment
- Macrophages clean up, Stim schwann cells
- Schwann cells proliferate (Neurotrophins)
- Schwann cells + BL guide neurons
What is a neuroma?
Lost axons that form a swelling when they cannot find their target, can be the source of spontaneous pain
In what time period must motor neurons reach muscle after damage?
-18 months
In what time period must sensory neurons reach target after damage?
-No time limit
What is the function of satellite cells?
- Form an intimate covering layer over the cell bodies in PNS ganglia
- Exert a supportive effect, nourishing and regulating the microenvironments of these neurons
What does endoneurium consist of?
- reticular fibers
- scattered fibroblasts
- capillaries
What is the function of the perineurium?
- regulated diffusion into the fascicle
- make up blood-nerve barrier to maintain fibers’ microenvironment
