Term
| Why do neurons need a high metabolic activity and lots of ATP? |
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Definition
| to maintain membrane potential during action potentials |
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Term
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Definition
| Nerve cell body - often triangular |
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Term
| Describe the nucleus of a nerve. (7 things) |
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Definition
- uncoiled chromosomes (euchromatin)
- large nucleoli for active transcription of lots of protein
- nissl substance (ER clusters0
- RER (not found at axon hillock)
- lots of Golgi
- mitochondria
- neurofilaments (intermediate) that are argyrophilic
- lipofuscin - junk accumulating in long lived cells |
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Term
| Describe dendritic structure of a nerve |
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Definition
it is an input structure
- microtubules and neurofilaments for transport
- dendritic arbor to increase SA and increase inputs (1000 per neuron)
- sparse ribosomes |
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Term
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Definition
it is the output structure
- microtibules (polymers of tubulin) and neurofilaments for transport
- plasma membrane
- axon sheath
- may be myelinated or not
- branch at terminal forming preterminal axons before synapsing |
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Term
| What are the components of the plasma membrane of an axon? (3) |
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Definition
1. axolemma
2. cytoplasm
3. axoplasm |
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Term
| How is the axon sheath formed? |
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Definition
| oligodendrocytes in CNS and Schwann cells in the PNS |
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Term
| Anterograde axoplasm transport flow |
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Definition
macromolecules are transported from the cell body to the axon terminal
- requires kinesin which is ATP dependent and microtubule dependent
- |
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Term
for anterograde flow:
- proteins and microfilaments move at a ___ speed at ___ mm/day
- organelles, vesicles for neurotransmission move at a ___ speed at ___ mm/day |
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Definition
slow - 1 mm/day
fast - 100 mm/day |
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Term
| Which proteins are used in anterograde v. retrograde axoplasm transport? |
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Definition
Kansas Awaits Dorothy's Return
kinesin - anterograde (away)
dynein - retrograde (towards the body of the nerve) |
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Term
| Retrograde axoplasm transport flow |
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Definition
fast flow towards the cell body with products of endocytosis such as toxins, viruses (useful in neuronal tracing experiements)
- uses Dynein which is ATP and microtubule dependent |
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Term
| What are the three types of neuronal morphologies? Where are they found? |
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Definition
1. mutlipoloar - most common - lots of processes, examples include the pyramidal and satellite cells
2. bipolar - rare - 1 axon and 1 dendrite - found in the retina, spiral ganglia of the ear
3. pseudounipolar - only sensory - 2 processes come together and fuse - found in the sensory cells of the DRG |
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Term
| How does the information flow in a nerve (impluse conductance)? |
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Definition
| dendrites to soma to axon to axon terminal |
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Term
| What contributes most to the blood brain barrier? |
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Definition
| nonfenstrated endothelial cells |
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Term
| Which type of glial cell derives from bone marrow? |
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Definition
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Term
which statement is false?
1. sympathetic neurons are efferent
2. postganglionic cells in the parasympathetic system are cholinergic
3. lipofuscin refers to vesicles containgin pigmented particles that are undegraded products from lysosomes
4. sensory neurons synapse in the DRG
5. the molecular layer of the cerebellum is mostly filled with large dendritic arbors of Purkinje cells, which accounts for the small number of nuclei here. |
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Definition
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Term
| Which type of glial cell is associated with gray matter? |
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Definition
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Term
| What makes up the presynaptic component of the synapse? post synaptic component? what do synaptic vesicles contain? |
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Definition
presynaptic - axon terminal with mitochondria, synaptic vesciles, and clathrin coated pits
postsynaptic - soma (axosomatic), dendrite (axodendritic) or another axon (axoaxonic)
synaptic vesicles contain neurotransmitters |
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Term
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Definition
| aggregates of receptors, signaling molecules and cytoskeletal proteins |
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Term
| where are electrical synapses found? What kind of synapses are found in humans? |
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Definition
they are gap junctions that are electrically coupled
- found in invertebrates
We have chemical synapses |
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Term
| What increases the SA of axon? |
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Definition
| dendritic number and spines |
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Term
| What do neurotransmitters do? |
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Definition
| they cause ion channels to open or close or initiate second messenger cascades |
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