Cerebrum, Meninges, Neuroglia , Brain Barriers Flashcards
The axons of …..end in deep cortical layers
Granule cells
Mention the spindle shaped cells in cerebrum
Fusiform cells
Horizontal cell of Cajal
The cell of ascending fibers is…..
Cell of Martinotti
The nerve cell found in molecular layer is…..
Horizontal cell
Enumerate layers of cerebral cortex
- Molecular layer
- External granular layer
- External pyramidal layer
- Internal granular layer
- Internal pyramidal layer
- Plexiform layer
Inner granular layer contains……(fibers)
Outer band of Baillarger
…….. contains large pyramidal cells. It also contains….
Inner pyramidal layer
Inner band of Baillarger
The pleomorphic layer contains……
Spindle-shaped cells, granule cells, stellate cells
Describe fibers of the cerebral cortex
-Radial fibers, ascedning (corticothalamic), descending (corticospinal, corticopontine, corticoreticular)
-Horizontal fibers, tangential fibers in first layer , outer and inner band of Baillarger which are branches of afferent fibers that bend horizotally to synapse with cortical cells.
Compare motor and sensory cortices
M, thickest zone, small and medium pyramidal cells in layer III, large in layer V, granule cells are rare or absent
S, relatively thinner than motor cortex, contains closely packed granule cells, pyramidal cells are ill-defined
The dura is formed of ……., inner surface is lined by……
Dense fibro-elastic CT
Simple squamous epithelium
The archnoid is formed of….&….
Flat membrane adjacent to dura
A system of trabeculae which is composed of collagen fibers and fibroblasts
Function of arachnoid villi
These villi help in CSF circulation from subarachnoid spaces into the blood sinuses of the dura.
Pial cells are joined by……, and separated from brain tissue by…..
Desmosomes, gap junctions and few tight junctions
Astrocytic processes
Describe composition of choroid plexus villi, and function
Each villus is formed of a central core of pia mater with fenestrated blood capillaries and covered by colmnar ependymal cells which line the brain ventricles
F, secretion of CSF
Mention caises of hydrocephalus
- Decrease absorption of CSF
- Obstruction of CSF outflow from ventricles
Neuroglia can be detected using……
Silver or gold impregnation method
Types of oligodendrocytes and their function
Light cells: predominant in CNS of fetus and neonate. They have large euchromatic nuclei and pale cytoplasm, capable of division
Dark cells: predominant in CNS of adults. Heterochromatic nuclei and dense cytoplasm.
Func: form myelin sheath in CNS each cell can form several internodal segments on the same or different axons.
Support neurons
Insulation of nerve impulses
Function of the pool of adult progenitor
Differentiate into oligodendrocytes and remyelinate, pathologicallu demyelinated regions
Astrocye feet are in contact with…….., connected by ….
Blood capillaries, neurons or nerve fibers
gap junctions
Mention contents of cytoplasm of astrocytes
Microtubules
Intermediate filaments (glial filaments) which is formed of glial fibrillary acid protein which is used as marker for brain tumor
Thread-like mitochondria
Describe Types of astrocytes
Fibrous astrocytes in white matter having long, thin processes
Protoplasmic astrocytes found mainly in grey matter have short extensive processes
Müller cells in retina, pituicytes in post pituitary
Mention functions of astrocytes
- Regulate metabolic exchange between neurons and blood
- Secrete factors regulate neural functions
- Regulate the EC ionic conc arpund neurons
- Regulate diameter of b.v. within CNS
- Support neurons
- Form part of BBB
- Repair processes by proliferation and formation of glial tissue (glial scar)
Mention functions of microglia
Phagoctes of CNS
Have receptors for NTs thus function in synaptic transmission
Phagoctose apoptotic cells during development
Describe site & shape of epemdymal cells
Si, lines the ventricles of brain and central canal of spinal cord
Sh, squamous, cuboidal or columnar. They do not rest on BM. Apical surface have numerous microvilli and/or cilia
Describe the epedymal cells lining 3rd and 4th ventricles
Have numerous microvilli but rarely cilia
Flattened basal nuclei
Numerous mitochondria
Joined by tight junctions and desomosmes
Mention functions of tanycytes
Have basal processes that faciliatate passage of hypothalamic-regulating hormones to pars disitalis of pit. gland
Enumerate fuctions of ependyma
Play a role in circulation of CSF by cilia
Absorptive function by microvilli
Some ependymal cells may be stem cells in adult brain but their portential for neural regeneration is under inverstigation
Mention components of blood-brain barrier
- The endothelial cells of Continuous blood capillaries with tight junctions
- Complete basement membarne of capillaries
- Pericytes with perivascular microglia
- Layer of perivascular astrocytic feet
Mention areas where BBB is lacking
- The endocrine regions as posterior pit and pineal body
- Hypothalamus which mointors plasma contents
- Choroid plexus where CSF is produces
Function of BBB
Protects brain tissue against toxic drugs and other harmful substances as bacteria present in blood
Mm
Mention components of blood-CSF barrier
- Endothelial cells of fenestrated blood capillaries
- Basement mebrane of endo. cells
- CT on which epedymal cells are resting
- Epedymal cells joined by apical junctional complex
Mention components of brain-CSF barrier
- Ependymal cells connected by apical junctional complex
- CT on which epedymal cells rest
- The foot processes of astrocytes
