Neuroanatomy Flashcards
What makes up the cytoskeleton?
Microfilaments, neurofilaments, microtubules and proteins
Properties of microfilaments
- 3-7nm in diameter
- Mostly polymer of actin
- Formed by 2 strands
- Found at the edge of the cell (cell cortex)
- Provides strength and shape, synaptic specialisation and learning and memory
Properties of neurofilaments
- 7-11nm in diameter
- Protein composition varies
- Provides up to 85% of total protein in the neurone
- Largest population in motoneurons
- Stabilises and strengthens axons, organises structure, can cause ALS when things go wrong
- Also known as intermediate filaments
Properties of microtubules
- 20-28nm in diameter
- Polymer of tubulin molecules
- Longitudinal arrangement in axons/dendrites
- Shape altered by polymerization
- They have microtubule-associated proteins (MAPs)
- Provide cell movement and axonal transport
How fast can axonal transport be?
100-400mm/day or 1mm/day
Orthograde vs retrograde axonal transport
Orthograde is from cell body to axonal terminal. Retrograde is from axonal terminal to cell body
Name the 2 molecular motors
Kinesin and dynein
What are the properties of kinesin?
- Orthograde transport
- Has amino terminal for ATP activity
- Divergent tail for movement
- Hydrolyses ATP to carry molecule along microtubules
What is dynein?
The same as kinesin but is used for retrograde transport
Name the glial cells in the CNS
Astrocytes, oligodendrocytes, microglia and ependymal
Name the glial cells in the PNS
Schwann cells and satellite cells
Properties of astrocytes
- Guide neurones during development
- Support neurones and capillaries
- Buffer extracellular ions
- Store and release neurotransmitters
- Allow glia-glia and glia-neurone communication
- Help the formation of the blood-brain barrier (BBB)
What is the blood-brain barrier (BBB)?
Maintains a stable chemical environment and immunological privilege of CNS
Properties of microglia
- Role in CNS immune response to infection or tissue damage
- Increases in numbers
- Releases growth factors
What do ependymal cells do?
Line the ventricles and central canal of spinal cord to help produce and control flow of Cerebrospinal Fluid (CSF)
Properties of oligodendrocytes
Myelination (insulation) of axons
What is the oligodendrocytes equivalent for PNS?
Schwann cells
What is multiple sclerosis?
An autoimmune disease which causes the destruction of myelin in the CNS
What are the symptoms of multiple sclerosis?
Fatigue, numbness, blurred vision and blindness
What is the PNS equivalent of multiple sclerosis?
Guillain Barre syndrome