NEUR 0010 - Chapter2 Flashcards
What does a Nissl stain do?
Stains the nuclei of all cells, as well as the clumps (Nissl bodies) surrounding neuron nuclei
Why are Nissl stains useful?
Distinguish neurons from glia, allows for study of cytoarchitecture of brain tissue (arrangement of neurons)
What does a Golgi staid do?
Stains a small percentage of neurons, but includes their neurites
What are the two main characteristics of an axon and its branches?
Uniform diameter, branches at right angles
How many axons does a cell body usually emit?
Just one!
What is Golgi’s view of the neuron organization
Reticular doctrine: neurites fuse into a network
What is Cajal’s view of the neuron organization?
Neuron doctrine: never connect and communicate by contact rather than continuity
What does it mean to alternatively splice a segment of mRNA?
To splice out some exons with the introns, which codes for a different protein; thus the same stretch of transcripted mRNA can lead to different proteins after splicing
What organelle “abounds” in neurons?
Rough ER, more than in glial cells or non-neuronal cells
How do we know there’s tons of RER in neurons?
They’re the Nissl bodies! They get stained.
What organelle comprises Nissl bodies?
RER
Where is the major site of protein synthesis in neurons?
RER
What is the difference between proteins synthesized on free ribosomes vs RER ribosomes?
Free = stay in cytoplasm; RER = used in cell membrane or organelles, woven into the RER membrane to be transported elsewhere
Why is there so much RER in neurons?
Because RER-synth proteins are used in membranes of cells or organelles, which make special membrane proteins that are so characteristic of neurons
How does some SER impact protein translation?
Helps fold proteins that jut from the RER into their 3D structures
What does the Golgi apparatus do?
Post-translational chemical processing of proteins; sorts and delivers
What are the characteristics of microtubules in neurons?
Big, longitudinally down neurites; thick-walled pipe; composed of tubulin stacked like pearls (polymer)
What are MAPs?
Microtubule-associated proteins: regulate microtubule assembly and function; anchor microtubules to each other and neuron parts
What is tau?
Pathological changes in axonal MAP, which plays a role in Alzheimer’s dementia
What are the characteristics of microfilaments in neurons?
Thin, numerous and longitudinal in neurites; two strands of actin polymers; changes cell shape; closely associated with and anchored to the neuronal membrane
What are the characteristics of neurofilaments in neurons?
Intermediate diameter; mechanically strong; multiple subunits (three woven protein strands) stacked
What distinguishes the axon hillock from the soma?
No RER, few free ribosomes, different membrane protein composition
What are axon collaterals?
Branches of the axon; often returns to communicate with the same cell that gave rise to it, or with neighboring dendrites (recurrent collaterals)
What are recurrent collaterals?
Axon collaterals that return to the axon, or to neighboring dendrites
