Neurons & Glia Flashcards
Differentiate between neurons & glia
- Neurons do the “doing” (process information, sense environmental changes, communicate changes to other neurons, command body responses)
- Glia is the “glue” (insulate, support and nourish neurons)
What is meant by “the neuron doctrine”
The theory of a neuron as a structural & functional unit of the nervous system, adhering to cell theory & communicating by contact (in opposition to the previously held view of a continuous reticulum)
What are the features of a Nissl stain and what are it’s uses?
- stain that binds to ribosomes (found in nucleus & cytoplasm)
- pretty much just cell bodies - good for cytoarchitecture of CNS. Not good for morphology
What are the features of a Golgi stain & its uses?
- metal-based stain
- Stains entire cell membrane including dendrites/axons
- Only a small % of cells stained will take up the stain (we don’t know why)
- So v good for cell morphology
What are the major structural features of the soma?
Soma (cell body)
* large nucleus & lots of mitochondria
What are neurites?
combined name for dendrites & acons (branches coming off the neuron)
What are the 3 components of the cytoskeleton and their function?
- Microfilaments & Microtubules - give structural integrity
- Microtubules - highways to get stuff from soma to terminal & back
What are the 3 regions of an axon?
- Axon hillock - beginning, important for AP generation
- Axon proper - middle bit, carries AP
- Axon terminal - end, release of NT in response to AP
What are the differences between the axon and soma?
- ER does not extend into Axon
- axon has unique proteins to assist in AP conduction
What are the properties of the axon terminal cytoplasm?
- No microtubules in terminal
- Presence of synaptic vesicles
- abundance of membrane proteins
- lots of mitochondria (lots of processing happens at the terminal)
What are the 2 directions of axoplasmic transport?
- Anterograde (soma to terminal)
- Retrograde (terminal to soma)
What products get moved down the axon by axoplasmic transport?
- NT
- cellular machinery
- neuropeptides
- cytoskeletal structures
Differentiate between fast and slow axoplasmic transport
Fast:
* both directions
* movement of proteins within vesicles
* 100-400mm/day
* movement along microtubules
Slow:
* anterograde only
* movement of cytoskeleton/cytoplasmic components
* much slower - transport motor dynein
* for growth & maintenance
What are the major structural features of dendrites?
- dendritic spines - point of communication with other neurons.
- post-synaptic density on dendritic spines
What are the different ways neurons can be classified?
- # neurites (unipolar, bipolar, multipolar)
- morphology (stellate [star], pyramidal, spinous vs aspinous)
- CNS connection (sensory, motor, interneuron)
- axonal length (Golgi type I [long projection neuron], Golgi type II [short local circuit neuron])
- NT type (e.g. dopaminergic)
- by gene expression
