Week 2: Neurons and Glia Flashcards
What is meant by “the neuron doctrine.”
Each neuron is a structural and functional unit. Neurons adhere to cell theory. Thought of following use of Golgi stain
Distinguish between the Nissl and Golgi stains.
The Golgi stain shows a small percentage of neurons in their entirety and are good for neuronal morphology. Nissl stains bind to DNA and RNA and so show the nuclei and cytoplasmic Nissl bodies: they show cytoarchitecture.
List the major structural features of the soma of a typical neuron.
The soma is the cell body. It is roughly spherical and approximately 20 micrometers in diameter. It contains a prominent nucleus and the cytoplasm (cytosol and all organelles except the nucleus).
List the major structural features of the axon of a typical neuron.
Axon hillock
Axon proper
Axon terminal
Axons are highly specialized. They transfer information over distances. They begin at the axon hillock, which tapers away from the soma to the axon proper. Axons often branch - branches are called axon collaterals. Recurrent collaterals returns to communicate to the same cell it’s from of neighbouring dendrites. Axons end in the axon terminal. The terminal usually appears as a swollen disk.
List the major structural features of the dendrites of a typical neuron.
Dendrites branch (called dendritic branches). Some have dendritic spines. Dendrites from a particular neuron collectively called dendritic tree.
List and describe the main components of the neuronal cytoskeleton.
Internal scaffolding of neuronal membrane has three structures:
• Microtubules
• Microfilaments
• Neurofilaments
What are the two mechanism of axoplasmic transport.
Slow axoplasmic transport
Fast axoplasmic transport
List the main ways that neurons may be classified.
- Number of neurites
- dendritic and somatic morphology
- connections
- axonal length
- neurotransmitter type
- gene expression
List the major types of glial cells.
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal cells
- Schwann cells
- Satellite cells
What was Cajal’s major contribution to neuroscience?
• Cajal’s contribution – Neural circuitry – Neurons communicate by contact, not continuity. • Neuron doctrine • Neurons adhere to cell theory. • Use of Golgi stain
What are two differences between axon and soma?
Differences between axon and soma:
– Rough ER does not extend into axon.
– Protein composition: unique
What is the difference between anterograde and retrograde transport?
Anterograde is soma to terminal
retrograde is terminal to soma
What is the function of microglia?
Equivalent to macrophages in other tissues - like the immune system. Remove debris.
other potential roles of microglial cells:
• reuptake of neurotransmitters (especially Glu);
• synaptic plasticity (memory/ adaptation);
• control of chemical environment (including blood-brain barrier)
• release of cytokines.
List the glia cells found in the PNS.
Schwann cells
2. Satellite cells
List the types of glia cells found in the CNS.
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal cells
How many neurites in the following types of neurons:
a. Unipolar
b. Multipolar
c. Bipolar
Unipolar: Single neurite
• Bipolar: two
• Multipolar: more
than two
What is the role of oligodendrocytes?
They form myelin sheaths in the CNS.
If an axon in the PNS is damaged, what happens?
Wallerian degeneration leads to removal of damaged axons and stimulation of growth factors to promote axon regrowth back into the periphery.
What causes the following process?
- prolonged breakdown of damaged axons
– an increase in the proliferation of astrocytes at the site of injury
– inhibition of axonal regrowth.
CNS injury
What is atypical about the amacrine cell of retina?
It has no axon
Based on dendritic and somatic morphology, star shaped neurons are called…?
a. Spiny
b. Stellate cells
c. Pyramidal cells
d. Aspinous
b. Stellate cells
List three major differences between fast axoplasmic transport and slow axoplasmic transport.
- Slow is Unidirectional while fast is bidierectional (Anterograde and retrograde)
- Fast involves proteins being enclosed in vesicles that move along the microtubules by kinesin.
- Slow is mostly at a rate of 1mm/day; fast can be up to 300mm/day
Which neuroglial forms myelin sheaths in the PNS?
The Schwann cell.
What precedes the atrophy of the axons and neurons distal to an injury site.
Loss of transmission across the injury
Based on dendritic and somatic morphology, star shaped neurons are called…?
a. Spiny
b. Stellate cells
c. Pyramidal cells
d. Aspinous
b. Stellate cells
What precedes the atrophy of the axons and neurons distal to an injury site.
Loss of transmission across the injury
What is a primary sensory neuron?
a. Cells with connections to the sensory surfaces of the body
b. Cells that form synapses with muscles
c. Cells with connections only with other neurons
d. Cells with dendritic spines
a. Cells with connections to the sensory surfaces of the body
Cells with dendritic spines are called…?
a. Spiny
b. Stellate cells
c. Pyramidal cells
d. Aspinous
a. Spiny
The most numerous glia in the brain is?
Astrocytes
Golgi Type I neurons are also called:
a. Local circuit neurons
b. Interneurons
c. Pyramidal cells
d. Projection neurons
d. Projection neurons
They have long axons that extend from one part of the brain to the other
Pyramidal cells are usually: (Select all that apply)
a. Golgi Type I neurons
b. Golgi Type II neurons
c. Projection neurons
d. Local circuit neurons
e. Spiny
f. Aspinous
g. Pyramid shaped
h. Classified by their dendritic and somatic morphology
i. In the cerebral cortex
a. Golgi Type I neurons
c. Projection neurons
e. Spiny
g. Pyramid shaped
h. Classified by their dendritic and somatic morphology
i. In the cerebral cortex
Pyramidal cells are usually: (Select all that apply) a. Golgi Type I neurons b. Golgi Type II neurons c. Projection neurons d. Local circuit neurons e. Spiny f. Aspinous g. Pyramid shaped h. Classified by their dendritic and somatic morphology i. In the cerebral cortex
a. Golgi Type I neurons
c. Projection neurons
e. Spiny
g. Pyramid shaped
h. Classified by their dendritic and somatic
morphology
i. In the cerebral cortex
What are Golgi Type II neurons?
Neurons with short axons that do not extend past the vicinity of the cell body. They are also called “local circuit neurons”. Stellate cells are examples of these.
