Cellular organisation of the nervous system Flashcards
(65 cards)
What did Golgi invent, and what did this allow?
a silver stain that allowed the staining of entire neurons (before this point only the cell bodies had been visualised under a microscope). It therefore allowed visualisation of neurites (processes)
What was the name of Golgi’s theory?
reticular theory
what was reticular theory?
that neurites (dendrites and axons) were fused together
Is reticular theory correct?
no (we now know that it is false)
Who used Golgi’s stian to make big discoveries?
Cajal
What was the name of Cajal’s theory?
the neurone doctrine
what did the neurone doctrine state?
that neurones are distinct cells (not fused together) which communicate by contact
Has well as the neurone doctrine, what else did Cajal find? (2)
neurons have a preferred direction in which they transmit information and that they don’t make connections at random (they only contact certain other neurones at particular points)
In more recent times, what 3 new technologies have allowed better understanding of the cellular structure of the nervous system?
- electron microscope
- fluorescence labelling techniques
- confocal microscopes
what did the development of the electron microscope allow?
the visualisation of cell ultrastructure (confirmed the existence of synapses)
What’s the disadvantage of Electron microscopes?
cells have to be dead to use this technique
What’s the principle of fluorescence labelling techniques?
- a selective antibody/ drug is tagged with a fluorescent label
- add tissue and allow to bind strongly to target protein
- wash off any free, labeled antibody/drug
- imaging to show fluorescence- distribution of binding
What’s the disadvantage of fluorescence labelling techniques?
it’s limited by the range of antibodies available
What is a confocal microscope?
uses lasers, high sensitivity cameras and imagine software to examine live cells/ physiology
what’s the disadvantage of a confocal microscope?
its resolution isn’t very high
What are the 2 major cell types of the nervous system?
Glia and Neurones
are there more glia or neurones in the brain?
it varies- they outnumber eachother at different regions
what’s the primary role of the glia?
to support neurons
what’s a major difference betwen glia and neurons?
glia can divide- neurons can’t
What are the 5 types of glia?
Astrocytes Oligodendriocytes Schwann cells Microglia Ependymal cells
What type of glia are the majority of glia?
astrocytes
What shape are astrocytes?
star
spatially what do astrocytes do?
fill space between neurons
what’s the role of astrocytes?
regulation composition of Extracellular fluid (may also have an important role in directing the proliferation and differentiation of neural stem cells)
