Neuro Specimens

7/31/2019 Neuro Specimens

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Neuroscience Practical Exam:

Reviewer

SY 2011-2012

Prepared by: Subsection C3 + C4


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Prayer Before Study

Lord, true source of light & wisdom

Give us a keen sense ofunderstanding, a retentive

memory & the capacity to grasp

things correctly.

Grant us the grace to be accurate in

our expositions & the skills to

express ourselves with

thoroughness and clarity.

Be with us a the start of our study,

guide its progress & bring it tocompletion

Grant this, through Christ our Lord

AMEN


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SPECIMEN: Notochord

-Involved in primary

neurulation

-Source ofinducer

substance to stimulate

underlying ectoderm tothicken & form the neural

plate

-Defines the long axis of

the embryo; determines

orientation of the

vertebral column


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SPECIMEN: Notochord

POINTED STRUCTURE:

Neural tube

-Gives rise to the CNS

-Rostral 2/3 -> brain

-Caudal 1/3 -> spinal

cord up to the lumbar

area

-After induction of the

notochord:

Neural plate -> [from day 18

to 25] neural groove

(indentation) & neural folds

(flap) -> neural tube (fusion

of neural folds)


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SPECIMEN: Primary brain

vesicle

POINTED STRUCTURE:

Anterior neuropore

Primary brain vesicle

-made up of forebrain

(prosencephalon), midbrain

(mesencephalon), and

hindbrain(rhombencephalon)

-Failure of fusion of anterior

neuropore will result to:

-Anencephaly ->absence of calvaria in

the skull

-Microcephaly ->

abnormally small skull

-Abnormal fascies


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SPECIMEN: Secondary

brain vesicle

POINTED STRUCTURE:

Telencephalic vesicle

Derived from the

forebrain:

- telencephalon

- diencephalon

Derived from the

hindbrain:

- metencephalon

- pons &cerebellum

(adult)

- myelencephalon

- medulla (adult)


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POINTED STRUCTURE:

Somite

-Adult derivations:

-Dermatome -> skin

innervation

-Sclerotome ->vertebra

-Myotome ->

muscular

innervation


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SPECIMEN: Substantia

nigra (midbrain)

POINTED STRUCTURE:

special pigmented

neuron


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SPECIMEN: Cerebral

cortex

POINTED STRUCTURE:

Cortical neuron

surrounded by

neuroglia/glial cells


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SPECIMEN: Cerebellum

STAIN: H&E

POINTED STRUCTURE:

Purkinje Cell

Layers of Cerebellum:

1. Molecular Layer

2. Purkinje Cell Layer

3. Granule Cell Layer

4. Deep White Matter

-according to length,Purkinje cell is:

-golgi cell type 1

(projection neuron)

3 1

2


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SPECIMEN: Spinal Cord

STAIN: H&E

POINTED STRUCTURE:Anterior Horn Cell / Neuron

-Multipolar neuron

-Motor function

-Intermediate sized Nissl

bodies at the periphery

-Fewer satellite cells

-Associated with

unmyelinated nerve fibers-Presence of synapse


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SPECIMEN: Spinal Ganglion

STAIN: H&E

POINTED STRUCTURE:

Ganglion Cell or Neuron

-Pseudounipolar

-Sensory function

-Fine Nissl bodies uniformlydispersed

-Presence of numerous

satellite cells

-Associated with myelinatedfibers

-No synapse


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SPECIMEN: Skeletal

muscle

STAIN: NADHPOINTED STRUCTURE:

type 1 fiber (dark staining)

-Type 1-more mitochondria

-lesser glycogen

-Type 2 (light staining)

-lesser mitochondria

-more glycogen


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SPECIMEN: Muscle

STAIN: modified

Gomori TrichomePOINTED STRUCTURE:

Muscle fiber

1. Tiny red dots -MITOCHONDRIA

2. Stained red or

purple - NUCLEI

2

1


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SPECIMEN: Muscle

STAIN: H&E

POINTED STRUCTURE:nuclei (peripherally

located)


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SPECIMEN: Muscle

STAIN: H&E

POINTED STRUCTURE:

Perimysium

Connective tissue coverings

of the skeletal muscle:

-Epimysium (outermost)

-Perimysium (in between

each fascicle)

-neurovascularstructures are found here

-Endomysium (each

muscle fiber)


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SPECIMEN: Osmicated teased

nerve fibers

STAIN: Osmium tetraoxide

(stains myelin black or brown)POINTED STRUCTURE (with the

arrowhead): Nodes of Ranvier

-Myelinated nerve fiber

-covered by myelin(whitish lipoprotein complex)

-produced by:

-PNS: Schwann cells

(one axon at a

time)-CNS:

Oligodendrocytes

(multiple myelination)


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SPECIMEN: Nerve

STAIN: H&E

POINTEDSTRUCTURE: Node

of Ranvier

Function: saltatory

nerve conduction


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SPECIMEN: Nerve

STAIN: Methylene blue

POINTED STRUCTURE:

Perineurium

-plays a role in the

formation of the blood-

nerve barrier-vasa nervorum

supplies blood to the

peripheral nerves


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DORSAL

VENTRAL

ventral median fissure

ventral gray horn

dorsal gray horn

dorsal median

sulcus

ventral funiculus

(white matter)

intermediate

zonelateral

funiculus

dorsal

funiculus

SPECIMEN C i l


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SPECIMEN: Cervical

spinal cord

-from C1 to C7

-passes ABOVEtheir corresponding

vertebra

-C8

-passes BELOW

CV7

Features:

-Relatively small dorsal

& ventral horns

-Thicker dorsal, lateral& ventral funiculi

-Due to thicker

white matter

-No intermediolateral

horn

SPECIMEN Th i i l


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SPECIMEN: Thoracic spinal nerve

POINTED STRUCTURE: Lateral

horn/Intermediolateral horn

-where the nucleus of the preganglionic

sympathetic nerve fibers are found

-located only in the lumbar spinal nerve

-Dorsal columns

-purely ascending fiber tracts

(sensory)

-responsible for conscious

proprioception

-2 types:

-Fasciculus cuneatus

-Laterally located

-Cervical to mid-thoracic level

-Upper extremities

-Fasciculus gracilis

-Medially located

-Lower extremities


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SPECIMEN:

Lumbar spinal

nerve

Feature:

-thicker gray horn-wider ventral

horn -> more

innervation->larger muscles

of the LE


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passage of

vertebral arteries

(O: subclavian

artery


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bifid spines


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pointed downwards

heart-shaped


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pointed horizontally

where the spinal nerve exits

kidney

shaped


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Neuro Specimens