Intro Lab - Anatomy CNS - Drg. Yuni

8/12/2019 Intro Lab - Anatomy CNS - Drg. Yuni

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Yuniarti

Department of anatomy

Faculty of medicine

UNISBA


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Organization of the nervous system

1.Central Nerve System

- Brain

- Spinal cord

2. Peripheral Nerve System

- Cranial nerve

- Spinal nerve


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Gyri: fold,which greatly increase the surface area of the cortex

Deepest groove between folds : fissure

Shallow groove between folds : sulci

The cerebrum is divided into left and right hemisphere by a longitudinalfissure

.


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The longitudinal fissure containsthe sickle-shaped fold of dura mater, the falx

cerebri, and the anterior cerebral arteries.

In the depths of the longitudinal fissure,the corpus callosum, connects the

hemispheres across the midline


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Each cerebral hemisphere is

divided into lobes:

~The Frontal lobe

occupies the area anterior to thecentral sulcus and superior to

the lateral sulcus

~The parietal lobe

occupies the area posterior to the

central sulcus and superior to thelateral sulcus

~The occipital lobe

occupies the small area behind

the parieto-occipital sulcus

~The temporal lobe

occupies the area inferior to the

lateral sulcus

~Insula lobe

Within lateral fissure


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Insula lobe


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Central sulcus : separate the frontal lobe from parietal lobe

Calcarine sulcus : between cuneus & lingual gyrus (Look at medial aspect) Parieto-occipital sulcus : separates the parietal lobe from the occipital lobe

Lateral sulcus : separates the frontal lobe from the temporal lobe.


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Internal Structure of the Cerebral Hemispheres

The cerebral

hemispheres arecovered with a layer of

gray matter, the cerebral

cortex.

Located in the interiorof the cerebral

hemispheres are the

lateral ventricles,

masses of gray matter,

the basal nuclei, and

nerve fibers. The nerve

fibers are embedded in

neuroglia and constitute

the white matter


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The Cerebral Cortex

Frontal (Forehead to top)Motor Cortex

Parietal (Top to rear)Sensory Cortex

Occipital (Back)Visual Cortex

Temporal (Above ears)Auditory Cortex


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The white matter is composed of myelinated nerve fibers ofdifferent diameters supported by neuroglia.

The nerve fibers may be classified into three groups

according to their connections:(1) commissural fibers

(2) association fibers

(3) projection fibers.


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1. Commisure fibers

Commissure fibers essentially connect corresponding regions of

the two hemispheres.

They are as follows:

- the corpus callosum*splenium

*genu

*rostrum

- the anterior commissure

- the posterior commissure

- the fornix

- the habenular commissure.


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2. Association fibers

Interconnect cortical regions within the same hemisphere

(a) Short association fibers

The short association fibers lie immediately beneath

the cortex and connect adjacent gyri; these fibers run

transversely to the long axis of the sulci.

-
http://3.bp.blogspot.com/_kaQ5P19FVgk/TVGN_s-LIhI/AAAAAAAAHhg/biiVZtW4SbA/s1600/Uncinate_Fasciculus.JPG


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(b)Long association fibers

Link one lobe with another

The superior longitudinal fasciculus

The arcuate fasciculus

The inferior longitudinal fasciculus

-The uncinate fasciculus

The cingulum

The fronto-occipital fasciculus


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3. Projection fibers

Contain axonsthat conduct nerveimpulses from the

cerebrum

Lower parts of the

CNS (thalamus,brainstem, spinal

cord)

Lower parts of theCNS (thalamus,brainstem, spinal

cord)

Cerebrum


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The cerebellum , the second-largest part of the brain

The cerebellum is posterior to the medulla and pons & inferior to the

posterior portion of the cerebrum


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In superior /inferior views,

the shape of the cerebellum

is somewhat like a

butterfly

The central constricted

area is the vermis

The lateral is cerebellar

hemispheres

Lobes :

- Anterior lobe

- Posrerior/middle lobe

- Flocculonodular


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Primary fissure :

Separated anterior

lobe & middle lobe

Horizontal fissure :Separated superior &

inferiot surface


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Have 2 part :- superfisial layercerebellar

cortex (gray matter)

- deep layerwhite matter

.

The cerebellar cortex has ridges

called folia.

The white matter of the medulla

resembles a branching tree and

is called the arbor vitae.


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Cerebellar Peduncles

The superior cerebellar peduncles connect the cerebellum to the midbrain

The middle cerebellar peduncles connect the cerebellum to the pons

The inferior cerebellar peduncles connect the cerebellum to the medulla

oblongata.


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Diencephalon isthe part of brain between the brainstem and the

cerebrum,surround the third ventricle


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Its main component are:

-Thalamus

-Subthalamus

-Epithalamus

-Hypothalamus


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epithalamus


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The hypothalamus is a small part of the diencephalon located inferior to

the thalamus


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Brainstem is the part of the brain between the spinal cord andthe diencephalon

It consist of three structurally and functionally connected regions :

1. Medulla oblongata2. Pons

3. Midbrain


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The midbrain extends

From the pons to the

Diencephalon

Is about 2,5 cm long


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The anterior part of the midbrain contains a pair of tract

called cerebral peduncles

Cerebral peduncle contain:

- axon of corticospinal, corticopontine, corticobulbar motor neurons whichconduct nerve impulses from the cerebrum to the spinal cord, medulla

and pons.

- axon s of sensory neurons that extend from the medulla to the thalamus


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The midbrain comprises two lateral halves, called the cerebral peduncles;

each of these is divided into :

-an anterior part, the crus cerebri

-a posterior part, the tegmentum

by a pigmented band of gray matter, the substantia nigra

O th l t l t f th idb i


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On the lateral aspect of the midbrain :

-The superior brachiumpasses from the superior colliculus to the lateral

geniculate body and the optic tract.

- The inferior brachiumconnects the inferior colliculus to the medial geniculate

body.


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The posterior part of the midbrain, called the tectum

Contains four rounded elevations :

- Two superior elevationssuperior colliculi (visual)

- Two inferior elevationsinferior colliculi (auditory)


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RESUME MIDBRAIN CONSIST OF

1. Cerebral peduncles crus cerebri & tegmentum DIVIDED by apigmented band of gray matter, the substantia nigra

2. Superior dan inferior brachium

3.Tectum (2 superior colliculi & 2 inferior colliculi)

4. Nuclei (red nuclei, substansia nigra, nuclei CN III & CN IV)


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The pons lies directly superior to the medulla and anterior to the cerebellum

Is about 2,5 cm long

Links cerebellum with mesencephalon, diencephalon, cerebrum, and spinal cord


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The anterior surface is convex from side to side and shows many transverse

fibers that converge on each side to form the middle cerebellar peduncle

There is a shallow groove in the midline, the basilar groove, which lodges the

basilar artery.


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Nuclei of the pons :

1. Pontine nuclei

are the sites at which signals for voluntary movements that originate inthe cerebral cortex are relayed into the cerebellum

2. Peumotaxic area & Apneustic area

together with the medullary rhythmicity area help control breathing

3. Nuclei associated with cranial nerve V(trigeminal),

VI(abdusent), VII(facial), VIII (vestibulocochlear)


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Medulla is a continuation of the spinal cord, it forms the inferior part

of brain stem


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On the anterior surface of the medulla is the anterior median fissure.

On each side of the median fissure, there is a swelling called the pyramid.

The pyramids are composed of bundles of nerve fibers, called corticospinal fibers

The pyramids taper inferiorly, and it is here that the majority of the descending fibers cross over to the

opposite side, forming the decussation of the pyramids


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Posterolateral to the pyramids are the olives, which are oval elevations produced by

the underlying inferior olivary nuclei.


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As in the spinal cord, the medulla oblongata consists of white matter and gray matter


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Nuclei of medulla :

1. The cardiovascular center

regulate the rate and force of the heartbeat and the diameter of blood vessels

2. The medullary rhythmicity arearespiratory center

3. Inferior olivaryrelay impulses from proprioceptors (monitoring joint &muscle positions)

to the cerebellum

4. Gracile & cuneatesensations of touch, conscious proprioception, pressure and vibration

5. Nuclei that receive sensory input from or provide motor output to

cranial nerve IX (glossopharyngeal), X (vagus), XI (accesorry) &

XII (hypoglossal)


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6. Solitary nucleus- receives

visceral sensory information

7 Olivary nuclei

lateral to pyramids. Receivesensory info from

proprioceptors (position) in

skeletal muscles & joints &

act as a relay point to the

cerebellum

8. Non-vital reflex centers

Vomiting, hiccough,

swallowing, coughing,

sneezing


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The brain is supplied

by the two internal

carotid and the two

vertebral arteries.

The internal carotid

arterybegins at the

bifurcation of the

common carotid artery

Enters the subarachnoid

space by piercing the

arachnoid mater and turns

posteriorly to the region of

the medial end of thelateral cerebral sulcus.

Here, it divides into the

anterior and middle

cerebral arteries


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The vertebral

artery

a branch of thefirst part of the

subclavian artery

ascends the neck

by passing

through theforamina in the

trasverse

processes of the

upper six cervical

vertebrae.

It enters the skull

through the

foramen magnum

The basilar artery


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The basilar artery

formed by the union

of the two vertebral

arteries, ascends ina groove on the anterior

surface of the pons.

At the upper border

of the pons,

it divides intothe two posterior

cerebral arteries.


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The circle of Willis lies in the

interpeduncular fossa at the

base of the brain.

It is formed by the

anastomosis between the two

internal carotid arteries and

the two vertebral arteries .

The anterior communicating,

anterior cerebral, internal

carotid, posterior

communicating, posterior

cerebral, and basilar arteriesall contribute to the circle.

Circle of Willis


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Th i l d b i ti ti


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The spinal cord begin as a continuation

of the medulla oblongata.

In adults, 42-45cm in long

Extend from the foramen magnum in theoccipital bone to the level of the L1 or L2

Enlarged in two regions :

1. Cervical enlargment (C4-T1 segment of

the spinal cord)

2. Lumbar/lumbosacral enlargment(T11-S1 segment of the spinal cord)

The medullary cone is tapering inferior end,

terminate as high as T12 vertebrae or

as low as L3 vertebrae

The spinal cord occupies only the superiortwo thirds of the vertebral canal


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Cauda equina is bundle ofspinal nerve roots

arising from the lumbosacral enlargment & the

medullary cone, caudal to the termination

of the spinal cord resembles a horses tail

Terminal filum :

-arising from the tip of the medullary cone,

descend among the spinal roots

in the cauda equina

-an anchor for the inferior end of spinal cord

and the spinal meninges


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Intro Lab - Anatomy CNS - Drg. Yuni