Neuroanatomy basics Flashcards
Glial Cells
Astrocytes
Oligodendrocytes
Ependymal cells
Microglia
What is the largest glial cell?
Astrocytes
Functions of astrocytes:
Regulating interstitial fluid
Regulates blood flow based on neuron activity
Structural part of blood brain barrier
Nutritional support (glycogen storage)
Activates antioxidant pathways
How do astrocytes help remove excess glutamate and GABA from synapses?
Expresses the enzyme glutamate synthase
What does VEGF do?
Decreases the stability of the blood-brain barrier with inflammatory conditions and CNS tumors
What is the immunohistochemical staining for astrocytes?
Glial fibrillary acidic protein (GFAP)
What is the role of glial fibrillary acid proteins (GFAP)?
Makes up intracellular intermediate filaments located in astrocytic processes
Which cell is responsible for formation of myelin in the central nervous system?
Oligodendrocytes
What is the function of myelin?
Provides electrical insulation that allows for saltatory conduction
What is the stain to ID myelinated fibers?
Luxol fast blue (LFB) staining
Which disease process likely involves lytic infection of oligodendrocytes to induce demyelination?
Progressive Multifocal Leukoencephalopathy (PML)
Oligodendrogliomas have what classic appearance on histology?
Chicken wire
How do oligodendrocytes talk to astrocytes?
Direct cell-cell gap junctions
Which leukodystrophy is caused by mutations in GFAP gene?
Alexander disease
What is the pathogenesis of alexander disease?
Accumulation of abnormal filaments, Rosenthal fibers in astrocytes.
Leads to oligodendrocyte death and demyelination
What occurs at a cell level in osmotic demyelination syndrome?
Astrocyte death is observed before oligodendrocyte death and demyelination
What do ependymal cells do?
Produces and facilitates the movement of cerebrospinal fluid (CSF)
Lines ventricles
What is the primary immune cell of the CNS?
Microglia?
How do microglia function?
Activates in response to tissue damage and ischemic injury
Becomes a motile, phagocytic cell (adept for neuronophagia) which forms reactive oxygen species and secretes cytokines and proteases
All glial and neuronal cells are derived from neural tube cells except:
Microglia
What is the function of neuronal cells?
Receiving, integrating, and propagating information to other cells
What are the 3 parts of a neuron?
Dendrites
Cell body
Axon
Which part of the neuron receives information from other neurons at synapses?
Dendrites
Basophilic clumps of polyribosomes in the cell body of a neuron are called:
Nissl bodies
What is the function of an axon?
Conducts information to muscles, glands, or neurons
What is the prototype cerebral neuron that has large, triangular cell bodies seen in the cortex and hippocampus?
Pyramidal Cells
GABAergic inhibitory interneurons that control Purkinje cell activity in the cerebellum
Stellate Cells
Upper motor neuron cells that are the largest neurons of the cerebral cortex
Betz Cells
What cells are predominantly affected by motor neuron diseases such as ALS?
Betz cells
Large distinct neurons in the cerebellum with a prominent pink cell body and extensive dendritic tree
Purkinje cells
Which cells are lost in cerebellar degeneration syndromes?
Purkinje cells
What stain can be used to easily seen neurons?
Silver staining
What occurs when axons of nerve are damaged?
Wallerian degeneration
Where do neurofibrillary tangles occur generally?
Amygdala
Hippocampus
Temporal association cortices
Where do amyloid plaques occur generally?
Neocortex of the frontal, parietal, and temporal lobes
What does the integrity of the blood brain barrier depend on?
Close apposition of the astrocytic endfeet to blood capillaries, endothelial cells, and a thick basement membrane
What cells for the inner walls of blood vessels and right junction in the BBB?
Endothelial cells
Cytotoxic edema occurs due to…
Cellular swelling, membrane breakdown, and cell death
Which areas of the brain lack a blood brain barrier?
Area postrema
Pineal gland
Posterior pituitary
Choroid plexus
Where is the area postrema found?
Dorsomedial medulla
Where is CSF produced?
Choroid plexus
Where is CSF reabsorbed?
Arachnoid granulations
What location is most CSF absorbed through (venous system)?
Superior sagittal sinus
How much CSF is present in the ventricles and subarachnoid space at any given time?
150 mL
How much CSF is produced in a day?
500 mL
Path of CSF flow
Enters 3rd ventricle trough foramen of Monro, then cerebral aqueduct then 4th ventricle
What causes hydrocephalous?
Excess production of CSF
Blockage of CSF circulation
Deficiency in CSF reabsorption
What is the most common cause of hydrocephalous?
Obstruction
What are the common causes of non-obstructive hydrocephalous?
Subarachnoid hemorrhage
Venous sinus thrombosis
Meningitis
What is seen on MRI in ventriculitis?
Appears as fluid levels within the cortical sulci and within the posterior horns of the lateral ventricles
3 layers of the cerebellar cortex
Molecular layer
Purkinje cell layer
Granular layer
Which is the outmost layer of the cortex which consistent of inhibitory neurons?
Molecular layer
What cells are in the molecular layer of the cortex?
Stellate and basket cells
Which is the middle layer of the cortex with inhibitory neuros?
Purkinje layer
What locations does the purkinje cells inhibit via cerebellar output?
Deep cerebellar and vestibular nucleus
What is the innermost layer of the cortex?
Granular layer
What does the granular layer of the cortex consist of?
Granule cells
Golgi interneuronsWh
Which cells are the only cells that are excitatory in the corex?
Granular cells
