Basic Neuroanatomy

Question 1

What is cytoskeleton and where are thy present ?

Answer 1

Network of filamentous structures
Present in all cells but complex structures of neurones mean certain specialities .

Question 2

What is the structure of a microfilament and what is its roles ?

Answer 2

STRUCTURE
- Diameter = 3-7nm
- Mostly polymer of globular protein, actin
- Two strands intertwine to form microfilaments
- prevalent at edge of cell = cell cortex

ROLES INCLUDE
SUPPORT
- Basic strength and shape of cells
- Pre and post synaptic specialisations
MOVEMENT
- Dendritic movements

Question 3

Whats a neurofilament and what are there roles ?

Answer 3

STRUCTURE

• Diameter = 7 - 11 nm
• Protein composition dependent on cell type
• Up to 85% of total protein in neurone
• Largest population in motor neurones.

ROLES
- Stabilise and strengthen axons
- Organise internal structure
- Neurodegenerative disorders

Question 4

Whats the structure of microtubules and its role ?

Answer 4

STRUCTURE
- Diameter = 20-28 nm
- Polymer of tubulin molecules
- Longitudinal arrangement in axons
- Neuronal shape altered by polymerization

ROLES
- Cell movement
- Axonal transport

Question 5

Whats organelle is absent in axons and nerve terminals and how are proteins transported ?

Answer 5

Ribsomes absent in axons and nerve terminals

Transport of proteins in vesicles

Question 6

Whats orthograde transport and how does it and what does it use to directs kinesis ?

Answer 6

Amino terminal = motor domain
Divergent tail = directs kinesin to a particular organelle
Uses hydrolysis of AYP to carry molecules along static microtubules.

Question 7

What are 4 types of neuroglia in the CNS ?

Answer 7

• Astrocytes
• Oligodenrocytes
• Microglia
• Ependymal cells

Question 8

What are 2 types of neuroglia in the PNS ?

Answer 8

• Schwann cells
• Satellite cells

Question 9

What are the 7 functions of astrocytes ( star cells ) ?

Answer 9

1. Guides neurones during development
2. Structural support for neurones and capillaries
3. Nourishment of neurones
4. Buffer extracellular ions
5. Uptake, store and release certain neurotransmitters
6. Participate in glia-glia and glia-neurone communication via chemical signalling.
7. Participate in formation of blood-brain barrier

Question 10

How do astrocytes mean capillaries are selectively permeable ?

Answer 10

Astrocytes maintain tight junctions between endothelial cells in capillary walls
Thus capillaries selectively permeable

Question 11

What is the blood brain barrier not effect for ?

Answer 11

Gases and fat-soluble substances

Question 12

What does the blood brain barrier maintain ?

Answer 12

1. Stable chemical environment
2. Immunological privilege of cns

Question 13

What is the function of a Microglia ?

Answer 13

• SPECIALIZED MACROPHAGES
• Important role in CNS immune response to infection or tissue damages
• Dramatic increase in number
• Phagocytic
• RELEASE GROWTH FACTORS

Question 14

Whats the function of Ependymal cells ?

Answer 14

• Line the ventricles and central canal of spinal cord
• Many ciliated - help produce and facilitate flow of CSF

Question 15

Whats the function of oligodendrocytes ( few branched cells ) ?

Answer 15

• Myelination of axons
• One can do whole axon
• several axons
• Function of Schwann cell in PNS
• one cell per myelin segment

Question 16

What is Multiple Sclerosis and what are the symptoms ?

Answer 16

Its the destruction of myelin in the CNS
About 100 000 people have it in the uk

SYMPTOMS
- fatigue
- loss of co-ordination and balance
-Numbness
-Blurred vision and blindness
- Paralysis