Lecture 2 - cells of the nervous system Flashcards
What are the 2 types of cells in the nervous system?
- Neurons
- Glia
What are neurons?
excitable cells that conduct impulses
What are the purpose of neurons?
integrate & relay information within a neural circuit
What are glia cells?
supporting cells - the ‘glue’
What is the purpose of glia cells?
maintain homeostasis, protection, assist neural function - assist in rapid transmission
How many neurons and glia cells are there?
85 billion of each cell type
What are neurons & glia cells both?
part of the neural circuits that make up the neural system
What does Nissl staining do?
- allows us to distinguish between neurons & glia
- nucleolus of all cells stained - this is because staining binds to negatively-charged molecules (RNA in the nucleolus)
Do neurons have Nissl bodies?
Yes, as well as a stained nucleolus
Do glia have Nissl bodies?
No, but they do have a stained nucleolus
How large are cell bodies?
Up to 50um
What is the purpose of Nissl staining?
allows visualisation of variation in size, density & distribution of neurons
What is the soma?
cell body (perikaryon)
What organelles are used for protein synthesis & processing?
- ribosomes
- rough ER
- Golgi apparatus
What is the function of mitochondria in neurons?
found in high quantity used by neurons to affect membrane potential
What are the 4 compartments of the neurons?
- Cell body, soma, perikaryon
- Dendrites
- Axons
- Presynaptic terminal
What are the neurites?
term for any process coming off neuronal body:
- dendrites
- axons
What is the Golgi (Camillo) stain?
this stain showed that neurones are more than just cell bodies, however doesn’t pick up all neurones
- silver chromate
- small%
Who used the golgi stain?
Santiago Ramon y Cajal - used Golgi stain and did drawings of the brain of different neurons.
What doesn’t the Golgi stain show?
synaptic terminal
Describe the cytoskeleton of a neuron
Microtubules - longitudinally down neurites & a hollow tube composed of polymers of tubulin
What is the axon hillock?
where the cell body transitions into the axon
What is the axon initial segment?
important for generation of action potentials (specialised area for action potentials)
What are axon collaterals?
(branches - often at right angles) - each collateral ends with a terminal