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17 Cards in this Set
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- Back
- 3rd side (hint)
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Neuron: organelles
Perikaryon: |
contains a large number of those organelles
forming a lot of products made of protein e.g. neurosecretory granules. These include |
E.R.,
Golgi apparatus, mitochondria. |
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Golgi apparatus
Only present in |
perikaryon
info |
Mitochondria
They are very numerous and lie between the Nissl substance and neurofibrils. They tend to be rather smaller than usual. Centrioles are rarely seen Primary and secondary lysosomes are common |
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Neuron: organelles
Cytoskeleton |
Neurofilaments
Neurotubules The cytoskeleton can be seen under the LM using silver staining techniques. It shows up as the neurofibrils. info |
The cytoskeleton can be seen under the LM using silver staining techniques. It shows up as the neurofibrils.
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Neuron: organelles
Cytoplasmic inclusions: |
Group 1-
vesicles concerned with neurotransmission e.g Group 2 - consists of pigments including: |
Group 1
Catecholamine Vasopressin oxytocin granules. A wide variety in the gastro-intestinal tract. Group 2 - Melanin- substantia nigra in the midbrain; spinal and sympathetic ganglia. Lipofuscin Iron occurs in various parts of the brain e.g. substantia nigra, globus pallidus. |
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Nerve cell processes
1, 2 or 3 ? = what are they ?= |
2
Dendrites - there are usually several. Axon - there is only one |
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Dendrites
Describe = |
Dendrites
Receive & integrate of axon terminal from other nerve cells. In neuroepithelium, they transduce one form of energy to nerve impulse. project directly from cell body and divide into a large number of spines (gemmules) the Purkinje cells of the cerebellar cortex there is a very extensive branching dendritic tree. |
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Describe physical charactristics of Dendrites:
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are thick at bases or origin and become thinner as they branch.
do not have Golgi apparatus are not myelinated |
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Dendrites have:
(in them 5ct =) |
rough E.R.
free ribosomes smooth E.R. mitochondria neurotubules and neurofilaments |
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Dendritic anterograde flow:
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acetylcholinesterase to degrade acetylcholine.
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Axon
The axon (also called |
axis cylinder
or nerve fiber is a single process of variable length The axon arises from a swelling on one side of the cell body called the = |
-axon hillock and forms initial segment
-which is not covered by myelin. |
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Axon
Sometimes side – branches, arise from the axon - they are always at |
right angles - and are called =.
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collaterals
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The axon contains =
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axoplasm which is directly continuous with the cytoplasm of the cell body
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Organelles in the axoplasm
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-Mitochondria - long and very thin
-Microfilaments provide support -Neurotubules – bundles and are active transport system -manufactured in cell body. -Smooth endoplasmic reticulum is present. -Nissl substance is not present |
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Axoplasmic Flow
The flow away from the cell body and down the axon is called = |
anterograde flow
whilst in the reverse direction it is called = |
retrograde flow.
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Anterograde flow - occurs at two speeds
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Fast: Kinesin mediated
(microtubule associated motor protein) requires ATP. 400 mm/ day Slow: 0.2 to 4mm/ day cytoskeletal components- |
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Axoplasmic Flow
Retrograde flow: occurs at about |
200 mm /day.
Cytoplasmic dynein (microtubule associated motor protein) mediated, requires ATP. |
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Note :
certain neurotoxins e.g. certain neurotropic viruses, e.g may enter the axon and reach the cell body by _________? flow. |
tetanus toxin
herpes and rabies retrograde flow |
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