Lecture 1- Neurons Flashcards
(30 cards)
Constituents of grey matter
Neuronal bodies (soma)
Dedrites
Axons
Associated glia
Constituents of white matter
Myelinated axons
Associated glia
H&E stain
Cell nucleus stains blue
Cytoplasm and connective tissue stains pink
Nissl stain
Differentiates between somatodendritic areas and axonal regions
Allows for visualisation of layers and cell densities
Myelin stain
Differentiates between grey matter and white matter
myelin or no myelin
Luxol blue stain
Nissle bodies stain purple and surrounding myelin fibers stain blue
Impregnation techniques
Whole morphology of neurons and glia
Immunohistochemistry
Technique for identifying expression of specific proteins such as neurotransmitters
Electron microscopy
For studying ultrastructure, fine structures within a cell eg: layers of myelin sheath
Neuron characteristics
Large soma
Prominent, euchromatic nucleolus
Nissl bodies throughout cytoplasm
Cytoplasmic extensions (dendrites and axon)
Nissl bodies
RER Free ribosome + mRNA= polysomes Polysomes + ER = RER Presence indicates protein synthesis RER makes proteins for secretion or incorporation into cell wall
Euchromatin
Active genetic material
Stains lighter
Often under active transcription
Types of neurons
Bipolar
Pseudounipolar
Multipolar
Bipolar neurons
Sensory neurons
Olfactory epithelium
Retina of eye
Ganglia of vestibulocochlear nerve
Pseudounipolar
Consists of 1 process which bifurcates into 2
-central and peripheral processes
Found in craniospinal ganglia
Multipolar
Most common
Cytoskeleton purpose
Required for neurons to form projections while maintaining their structure and functions
Composition of cytoskeleton
Microfilaments
Neurofilaments
Microtubules
Microfilaments
Consist of 2 strands of actin twisted around each other
Found throughout neurons and glia
Enriched in areas near plasmalemma, presynaptic terminals, dendritic spines and growth cones
NB during development, regeneration and repair)
Neurofilaments
Heteropolymers, from from NFH, NFM + NFL for low, medium and high molecular-weight subunits
Make up the bulk of axonal volume in large, myelinated fibers
Represent a large fraction of total protein of the brain
Provide mechanical strength and a stable cytoskeletal framework
Regulate cellular and axonal volumes
Unusual degree of metabolic stability, therefore well suited for a role in stabilisation and maintenance
Microtubules
a- and b-tubulin subunits
The route to transport substances to different parts of cell
Several microtubule-associated proteins (MAP’s) are expressed only in neurons and be localised specifically to either axons or dendrites
Taupathies
Heterogeneous neurodegenerative disorders Alzheimers Progressive supranuclear palsy Corticobasal syndrome Frontotemporal dementias Chronic traumatic encephalopathy
Anterograde transport
process by which fresh components are continuously made in soma of neuron and moved into axon and dendrites
Neuron conduction process
Potential generated in somatodendritic region, action potential generated at axon hillock and propagated along axon towards axon terminal to effector organs or postsynaptic neuron
