3:L10 Flashcards
Difference in grey/white matter location in CNS and Peripheral
- White (inner)- myelinated fibres that extend to other areas
- Grey- cell body, nuclei
SP: - These grey centralised (protection as cell bodies inside, + easily located)
Difference between ventral and dorsal halves
dorsal half — sensory roots & ganglia
• ventral half — motor roots (auto and somatic to prephiery)
5 Types of glia cells
Astrocyte
ologiodendrocytes
ependymal
olfactory ensheathing glia
where do glia and neutrons service from
neuroectoderm
where are o Oligodendrocytes, astrocytes and ependymal cells derived from compared to o Schwann cells and satellite cells
o Oligodendrocytes, astrocytes and ependymal cells from ventricular zone of neural tube
o Schwann cells and satellite cells from neural crest
where are microglia derived from
derived from hematopoietic stem cells
6 major stags in neural development
- Neural precursor cells (NPCs) from ectoderm
- NPCs Differentiation into NEURONS and GLIA
- Migration to target site involving:
- Axon extension
- Synaptic connectivity (type, number and cellular location) (if non= rejected or non functional system)
- Modification of neural connections
Overall function for radial glial cells
• Act as a scaffold for migrating neurons and glial progenitors
What do radial glial cells turn into
astrocytes + neurons
Glial cell function in developmnent
o Guidance of neurogenesis, neuronal growth and migration
o Trophic influences (sustainance, molecules that maintain viablity)
o Synaptogenesis (formation of synapses)
o Myelination and formation of vasculature
Glial cell function in adult life
o Blood Brain Barrier (BBB)
o Regulation of blood flow
o Maintenance of neural environment (ion/pH buffering, role at synapses, neurotransmitter recycling, metabolism, etc.)
Glial cell function in injury
o Phagocytosis, proliferation and scarring, either -ve or +ve influence on plasticity and growth, immune mediation, etc.
how can someone identify astrocytes
multiple branches
fuses to other astro, blood vessels, synapses
GFAP +ve filaments
what is a syncytial network
- Fusing of astrocytes to form one system
what do astrocytes do during innjury
• When injured they change morphology + secrete molecules (=activated)
If not bad injury go back to non activated state
If bad injury= stay activated> form glial scar to seal of injury site
what is oligodendrocytes function
myeline ate
describe microglial function
- Small cells, resting and activated states
- Activated in pathological states and trauma
- Motile antigen expressing cells – role in immune responses
- Able to secrete factors that can influence angiogenesis and astrocyte proliferation (complex interactions)
what are olfactory ensheathing glia
- Persistent renewal of olfactory pathway throughout life
* Therefore OEGs may be able to support axonal growth and regeneration in adult brain
what are schwann cells equiv to
oligo but in PNS
function of schwann cells
- Myelination
- Phagocytic activity
- Trophic support
- Modulation of synaptic activity
- Presentation of antigens
what are growth and trophic factors
Soluble/diffusible factors - polypeptides
what is retro/anterograde transport of growth factors
- Retrograde (brain> periph) and anterograde transport (periphery > brain)
- Targets (need to find otherwise will die)
what is paracrine/autocrine fucnctions for growth factors
• Paracrine (between cells) and autocrine (within cells) functions
Describe link between retrograde + neuronal viability and phenotype
Target independency/dependency:
• If not connected yet and target removed= can survive and find new target
• If connected (dependent) and target removed= dies
Name 3 examples of growth and trophic factors in the neurotrophic family
• Nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3
4 types of cues for axon extension
graded axon guidance cues
homophobic adhesion cues
axon-axon recognition cues
sub-cellular adhesion cues
what are attraction and repulsive cues for growth cone
Attractive = leads to asymmetric synthesis of β-actin on side near to source of gradient > attractive turning of cone
Repulsive
activate axonal translation of actin-depolymerizing proteins RHOA and cofilin when uniformly applied in cell culture.
example of attractive and repulsive cues
Attractive cues, e.g. netrin 1 & BDNF,
Repulsive cues, e.g. SEMA3A and SLIT2
Describe attraction example in spinal cord
- As neuron develop: dorsal molecules heads towards netrin (target dependent) which is being produced at ventral
- TAG/NCAM (involved in this process) are then turned off and L1 at distal alters trajectory and neuron follows = development needs these intermediates to guide axon through terrain
what growth factors increase and decrease with age
o Increased GFAP espression with age in certain areas of brain
- BDFN decreases with age (in hippocampus)
