Histology of the Nervous System Flashcards
The outer layer of the cerebellum is the cortex, composed of three layers. What are they?
- Outer layer is the molecular layer, composed of neuron cell bodies.
- Middle layer is the Purkinje cell layer, composed of large multipolar neurons called Purkinje cells that have important inhibitory functions.
- Innermost layer is the granular layer, composed of the smallest neuron cell bodies.
What is a perikaryon?
Neuron cell body.
Where are astrocytes located and what is their function?
Located in the CNS.
Important for blood brain barrier.
Star-shaped glial cells that have many projections.
What are oligodendrocytes?
CNS, important for myelination.
Extend several paddle-like projections from the cell body, each forming a myelin sheath around an axon.
What are microglial cells?
CNS, important for immune defence.
Small, oval-shaped cells with long slender processes that extend from the cell.
What are ependymal cells?
CNS, important for production of CSF.
Feature cilia to beat and circulate the CSF.
Why do myelinated axons have clear staining?
Due to the fatty myelin produced by Schwann cellls.
What is the central canal of the spinal cord?
Narrow tube-like space within the spinal cord, filled with CSF, lined by ependymal cells.
What is the endoneurium?
Basement membrane that surrounds each axon.
What is the perineurium?
Connective tissue surrounding a bundle of axons.
Provides vascular supply and nutrients.
What is the epineurium?
Dense connective tissue that surrounds an entire nerve.
What are satellite cells?
Glial cells that ensheath the surface of nerve cell bodies.
What are schwann cells?
Supportive glial cells within the PNS that provide myelination to individual neuron axons.
Each peripheral nerve contains thousands of ?
Axons
Nerve fibres are grouped into bundles called ?, each of which is surrounded by ?
Fascicles, perineurium
Compare and contrast unipolar/pseudounipolar, bipolar and multipolar neurons
unipolar/pseudounipolar - single dendrite. axon arises from a common stem of the cell body.
bipolar - single dendrite. axon arises from the pole of the cell body opposite to the origin of the axon.
multipolar - numerous dendrites project from the cell body.
Are sensory, motor and interneurons unipolar/pseudounipolar, bipolar or multipolar? What do they look like?
sensory neurons - unipolar/pseudounipolar
motor neurons - multipolar
interneurons - bipolar
What are the main components of a typical neuron and what are their functions?
What is the CNS composed of and what does it contain?
What is the PNS composed of and what does it contain?
