Micro Block 4

What are the two parts of the central nervous system?

Brain

Spinal Cord

What are the two cell types of nervous tissue?

Nerve cells

Neuroglia

What are the 2 types of nerve cells?

Neurons-in CNS

Ganglion-in PNS

What are the 4 neuroglia of the CNS?

Astrocytes

ogliodendroglia

microglial cells

ependymal cells

What are the two types of neuroglia of the PNS?

Schwann cells

Satellite cells

What are meninges?

A series of connective tissue sheaths that envelop the brain,spinal cord, roots of the peripheral nerve and optic nerve

Is the optic nerve considered CNS?

yes

What are the layers of the meninges in order from furthest outside to furthest inside?

Dura mater

Arachnoid

Pia Mater

what is leptomeninges?

the arachnoid and pia mater

What layer of the meninges contains cerebrospinal fluid?

subarachnoid space

What does pia mater adhere to?

brain and spinal cord

which layer of the meninges is highly vacular?

pia mater

when looking at meninges how tell which layer is the archnoid?

looks spider web like (and an arachnid is a spider)

Does the spinal cord have the same meninges layers as the brain?

Yes

what becomes the neural tube? what does it consist of?

The neural plate consisting of neuroectoderm

What does the neural tube give rise to?

-All cells of CNS (neurons,astrocytes,ogliodendrocytes,ependymal cells,choroid plexus cells)

-All the nerves that innervate skeletal muscle

what does the neural crest cells give rise to?

-Arachnoid and pia mater

-enteric parasympathetic ganglia

-schwann cells

-dorsal root ganglia

what does the mesoderm give rise to?

-dura mater

-connective tissue around peripheral nerves

what two terms for the forebrain embryonic brain division?

Telencephalon

Diencephalon

What derives from the Telencephalon?

Cerebrum

hippocamus

amygdala

basal nuclei

What derives from the Diencephalon?

Thalamus

Hypothalamus

what term for the midbrain embryonic brain division?

Mesencephalon

What derives from the Mesencephalon?

Midbrain

what two terms for the hindbrain embryonic brain division?

Metencephalon

Myelencephalon

What derives from the Metencephalon?

Pons

Cerebellum

What derives from the Myelencephalon?

Medulla oblongata

What are 3 structural elements of the cerebrum? describe each

Sulcus-grooves/pits

Gyrus-ridge

Fissure-deep clefts separating major regions, lobes or hemispheres

What are 2 structural parts of the cerebellum? describe

Vermis- narrow midline region

Folia-leaflike folds on cerebellar cortex

What are the 5 areas the spine can be functionally divided into?

C1-C5

C6-T2

T3-L3

L4-S1

S1-S3

What are cells of ectodermal origin very sensitive to?

Hypoxia

What are 3 neuronal cells of ectodermal origin?

neurons

astrocytes

ogliodendrocytes

what are 2 cells of mesodermal origin?

microglia

vascular epithelium

what is neuron?

Cells in CNS responsible for transmitting electrical signals throughout body

What is the general function of glial cells?

Support system in which neurons are embedded and serve many critical functions

What call neuron cell body?

Perikaryon or soma

What branch off neuron cell body?

dendrites and axon

What are 2 characteristics/properties that define neurons? describe each

irritability: the ability to generate an electrical impulse

conductivity: the ability to tansmit one such an impulse from one locality to another

what nucleus type do neurons have?

euchromatic with a prominent nucleolus

What call the basophilic cytoplasm of a neuron? what does it contain?

Nissl substance

-Rough ER and ribosomes

What is a synapse?

Specialized junction or gap where a neuron communicates with another cell

what 3 things can neurons synapse with?

nurons

muscle

glands

Because neurons are long living what can be seen inside some of them?

lipofuscin

what 3 ways can neurons be distributed?

Individually

layers

groups

where see neurons in layers?

the cerebral and cerebellar cortex

What stain use to see lipofusin?

PAS

What stains used to evaluate myelin? what do?

Luxol fast blue -stains myelin blue

Osmium tetroxide alpha naphthylamine method- stains normal myelin a brown/orange color and damaged myelin black

what call a groups of neurons in CNS? what about in PNS?

CNS: nuclei

PNS: ganglia

What are 4 glial cells of the CNS?

Ogliodendrocytes

Microglia

Astrocytes

Ependymal cells

What is functions of ogliodendrocytes?

-Support neurons

-Form myelin sheaths for several axons at once

What are oligodendrocytes best visualized with? what do stain do?

Silver stains: stain them black

Osmium tetroxide alpha naphthylamine method

Immunohistochemical stain: detect Olig2

what are the resident macropahges of the CNS?

microglia

which glial cells are the smallest?

Microglia

what are 3 functions of microglia?

-immunosurveillance (includeing antigen presentation)

-immunoregulation

-phagocytic function during inflammation and repair

what call activated microglia cells? when do they activate?

Myelophages (gitter cells)

activate during conditions causing inflammation or cell death

How do gitter cells appear microscopically?

lobular and swollen after having phagocytized debris

what call it when myelophages in a myelin sheath?

digestion chamber

What is the CNS counterpart of a fibroblast?

Astrocytes

what are the 2 types of astrocytes? where found?

Protoplasmic-grey matter

Fibrillar-white matter

how visualize astrocytes?

Use IHC that reacts with glial fibrillary acidic protein (GFAP)

What is glial fibrillary acidic protein made in abundance by?

astrocytes

What are 4 functions of astrocytes? what are its biggest 2?

-Cell communication

-Crucial component of blood brain barrier

-Transport nutrients

-antigen presentation

Describe how astrocytes, microglia and ogliodendrocytes appear on slide?

astrocytes: large circular eucharomatic nuclei and can rarely see cytoplasam or cell membrane in Hand E

microglia: very very small basophilic nucleus with little cytoplasam

ogliodendrocytes: slightly larger than microglia and have dense round nuclei surrounded by clear zone so look like a fried egg

what is white matter? what called in greek?

Accumulation of myelinated axons along with other glial cells

-Leukos

are there neuronal cell bodies in white matter?

NO

why does white matter appear white?

myelin is lipid rich giving white appearance as lots of myelinated axons in white matter

what is gray matter? what called in greek?

Neuronal cell bodies along with glial cells

-Polios

what is neurophil?

axons,dendrites, and cytoplasmic projections of glial cells that form matrix of gray matter

in cerebrum where is white matter? where is gray?

gray outside

white inside

in spinal cord where is white matter? where is gray?

white outside

gray inside

does grey matter contain axons and dendrites of neurons?

yes

which layer of the meninges contains CSF?

Subarachnoid space

What cell in the CNS myelinates axons?

oligodendrocytes

How tell you are looking at cerebellum?

has 3 layers in grey matter

what is grey matter called in cerebellum?

cortex cerebelli

What are the 3 layers in cerebellum grey matter? describe each?

molecular level-outer most layer with neurons called basket cells

ganglionic layer-border between molecular layer and granular cell layer and has neurons called purkinje cells

granular cell layer-inner layer with neurons called granule cells

what is white matter in cerebellum known as?

corpus medullare or arbor vitae

what predominates in cerebeullum white matter?

myelinated axon tracts

How to tell if medullla oblongada on slide?

Can’t really tell if white matter is on inside or outside and can’t tell if gray matter is on inside or outside

what tells you that looking at neonatal cerebellum?

Has 4 layers with its outer layer being called the exterior cortical layer

Which has three layers the cerebrum or cerebellum?

Cerebellum

what found in ventral horns of spinal cord?

motor neurons whose axons make up the ventral roots of the spinal nerves

what found in dorsal horns of spinal cord?

sensory fibers from neurons in the spinal ganglia

when looking at spinal chord which are ventral horns?

longer wings of butterfly (on same side as longer fissure)

Are spinal cord nerves multipolar?

yes

what is ependyma?

thin epithelium that lines the fluid filled spaces of the CNA

what is ependymal cells?

the cells lining the fluid filled spaces residing on the ependyma

How do ependymal cells look?

cubordal or columnar with cilia and mircovilli

what is function of cilia on ependymal cells?

circulate CSF