Untitled Flashcards Set

basic structure and organells and function

What is the basic structure and function of neurons? What are the different organelles in the neuron and functions?

The neuron

• structure

  • unipolar

  • bipolar

  • multipolar

• functions

  • afferent

    • The sensory/receptor neurons

    • Carry impulses towards the CNS

  • efferent

    • Conduct impulses away from the CNS

  • interneurons

    • Facilitate interaction between neurons

• Basic characteristics of a neuron

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neurogenesis

• Developmental neurogenesis

  • Most stem cells die by the age of 13

    • Can not be replaced

    • Can not go back to the previous developmental stage

• Adult neurogenesis

  • Confined in 2 regions in the brain

    • Subventricular zone

      • Glia and neurons in olfactory bulb

      • Cell grow during pregnancy

        • Potentially due to hormonal change

    • Subgranular zone

      • hippocampus

• Vulnerability of cells

  • Terminally differentiated

    • Can not de-differentiate/divide to replenish

    • Only can regenerate in 2 sections once developed

    • Trigger axon sprouting, stem cell replacement as therapies

  • Reply on a continual supply of glucose and oxygen for energy

    • Lack energy storage, and rely on neighbouring cells

      • 60% of all glucose in the body is used in the brain

      • 60-70% of that is used to maintain membrane potential

specialised structure and types

What are specialized structural characteristics of a neuron and the different types?

signal transmission

How are signals transmitted between neurons?

glial cells types and functions

What are the different types and functions of glial cells ?

• 90% of the cells in the CNS

  • Modulatory role

  • Participate in neuronal signalling and survival

  • Communicate in a plastic bidirectional manner

  • Display cellular memory akin to neuronal plasticity

• Can cause damage to other glial cells and other neurons

• macroglia

• Oligodendrocytes

  • Terminally differentiated

• Schwann cells

• astrocytes

  • High reactive

  • Not terminally differentiated

  • Can proliferate to damage/injury

• Ependymal cells

• Radial glial

• Satellite cells

• Microglia (immune system)

  • High reactive

  • Not terminally differentiated

  • Can proliferate to damage/injury

  • Innate immune cells of the CNS

    • Goes into the CNS in the embryonic development

    • 15% of the glial cells in adult CNS

    • Average of 4.2 years

      • ⅓ are replenished annually by local division

  • Macrophages: innate immune response

    • In the PNS

      • Only gets into the VNS when there are BBB damage

    • Derived from bone marrow

  • neuroinflammation

    • Increased activity in many NDD

      • Respond to deposition in local environment or deposition of mutant proteins

        • α synuclein, amyloid β, prion proteins

  • In healthy individuals

    • Normal brain microglia

      • Ramified long, branched processes

      • Quiescent, surveillant, homeostatic

      • Downregulate protein expression of iNOS

      • Comprised 10-20% of total population of glial cells

    • Reactive microglia

      • rounded , “fried-egg” morphology

      • Lysosome and phagosomes

      • Proliferative, phagocytic

      • Upregulated

        • protein expression of iNOS

A protein that catalysis the production of NO

Overproduction of which leads to DNA change

• membrane receptors

  • Cytokine secretion

IL1, IL6, TNFα, IFNγ

• phagocytosis

  • Clear debris, viruses, bacteria

  • Synaptic pruning

    • In development

    • In adults

Synaptic remodeling

Plasticity

• Involved in inappropriate synapse loss in NDD

  • Respond very quickly

    • Upregulated in acute situations

    • Downregulated in chronic conditions

  • In disease brain

    • Relates to the form

      • active/reactive

      • Amoeboid

      • ramified

    • Function

      • Anti-inflammatory v pro-inflammatory

      • M1 v M2

        • M1: induce inflammation and neurotoxicity

        • M2: anti-inflammation

      • Classical v alternative

      • Diseased associated microglia

neuron and glia interaction

How do neurons and glia interact in the brain? How do these benefit neurons? How may they be detrimental to neurons in relation to neuronal disease ?

genetic variations

What is the difference between genetic variations and what are the biological consequences of them?

medical conditions w genetic varients

What medical conditions are associated with specific types of genetic variants?

methodologies to identify variants

What methodologies are used to identify

Positron emission tomography (PET)

gene therapy

What is gene therapy