ELM2 - Cells of the Nervous System Flashcards
What is Golgi’s role in the history of the neuron?
Reduced silver stain so we can look at individual cells
Believed neurites were fused together in a reticular network
What was Cajal’s role in the history of the neuron?
Used Golgi’s stain to do drawings
Neuron doctrine theory each neuron is a discrete cell
Principle of dynamic depolarisation
Principle of connectional specificity
What is Cajal’s principle of dynamic polarisation?
Neurons transmit information in a certain direction
What is the principle of connectional specificity?
The structure of the nervous system is organised not random
What are some advantages and uses of electron microscope?
High resolution
Examine cell ultrastructure
Prove synapses exist
What are some disadvantages of electron microscopes?
Can only examine dead cells
What is the process of immunofluorescence labelling methods?
- Prepare antibody or drug tagged with fluorescent label
- Add to tissue and allow to bind so the target protein is labelled
- Wash off free labelled antibody
- Look and see what is fluorescent to see target protein distribution
What are confocal microscopes?
Combine lasers and fluorescence
Focus laser at different layers of tissue
What are the advantages of confocal microscopes?
Look at live cells
What are the disadvantages of confocal microscopes?
Resolution of 0.1um
What is meant by Brainbow?
Genetically modify animals so cells show different colours
Can trace pathway of neurons
What is the role of glia?
Support neurons
Regulate nervous system
Mediate signalling
Can divide
What are the glia in the CNS?
Ependymal cells
Oligodendrocytes
Astrocytes
Microglia
What are the glia in the PNS?
Satellite cells
Schwann cells
What are ependymal cells?
Line ventricles
Direct cell migration in development
Produce CSF Reserve of cells
What are oligodendrocytes?
Myelinate axons
Insulate many axons
What are astrocytes?
Star shaped
Fill space between neurons
Regulate extracellular fluid
Direct proliferation and differentiation of neural stem cells
What are microglia?
Phagocytic/immune function
Can migrate
What are schwann cells?
Myelinate axons
One per axon
How does Huntington’s develop?
Huntingtin gene codes for a mutant protein which isn’t broken down
It builds up and kills the cell
Basal ganglia most effected
What causes Alzheimer’s disease?
- Amyloid beta misfold and form plaques around neurons which kills them
- Tau are phosphorylated and clump and make tangles which disrupts normal cargo movement 3. This kills the neurons
What components are common between neurons and other cells?
Cell body with cytosol and organelles
Cell membrane
What components are unique to neurons?
Can’t divide
Can make action potentials
What are some ways polarity is caused in neurons?
Differences in organelles
Differences in the membrane and cytoplasm
How are different molecules and organelles targeted to different parts of the neuron?
The neuronal cytoskeleton
What is the function of the neuronal cytoskeleton?
Structural support
Transport cargo to and from axon and dendrites
Tether components to membrane
What are the 3 components of the neuronal cytoskeleon?
Microtubules
Neurofilaments
Microfilaments
What are microtubules?
Structural support 20nm wide
Polymerise and depolymerise to change neuron shape
What are neurofilaments?
Mechanical strength
10nm wide
Filamentous protein threads
What are microfilaments?
Mediate strength change
5nm wide
Actin polymers
Tethered to membrane
What are the different ways of classifying neurons?
Structural and functional
What is the structural classification of neurons?
Based on morphology or number of processes (neurites) coming from cell body
What are the 3 types of structural classification of neurons?
One process = Unipolar = Sensory
Two = Bipolar = Interneurons
2+ = Multipolar = Motor
What are the different functional classifications of neurons?
Sensory (a) = start at sensory receptors
Motor (e) = conduct signals from CNS
Interneurons = Between sensory and motor
How are neurons repaired in the CNS?
Damaged area colonized by glial cells
Block regrowth of axons
How are damaged neurons repaired in the PNS?
Schwann cells promote axon growth
