the brain 2 e-learning (1)

8/2/2019 The Brain 2 E-learning (1)

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The Brain II

Hindbrain, Ventricular System & Vasculature


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The Hindbrain

Made up:

Pons

Medulla oblongata

Cerebellum

Brain Stem?


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Pons

Middle part of brainstem

Ant. To cerebllum

Fxn.:Contains bundles of axons thatconnect the 2 halves of cerebellum

Contains the nuclei of cranial n. ??

Controls arousal


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Medulla Oblongata

Lower part of brainstem

Connects?

Important features:median fissure

2 lat. Pyramids:contain bundles of motor neuronslocated in precentral gyrus

2 olives

* Motor bundles cross over to opposite side atlower part of the medulla

* Contains nuclei of which C.N.??


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Cerebellum

1/10 of brain mass, yet of

neurons

Location:post. Cranial fossabeneath tentorium cerebelli

Fxn.:

coordination of muscle tone &movements on same side ofbody

Regulates posture & balance

*Ataxia: ?? Due to damage tocerebellum


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Meningeal Reflections


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Ventricular System of The BrainBrain Chambers

Consists of:

2 lat. Ventricles

3rd ventricle

4th ventricle

* Contain choroid plexuses

CSFChoroid plexus, 3 layers ?1] the capillary network

2] pia matter

3] epindemal cells


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Lateral Ventricles

Located within cerebrum

2 large cavities that filled withCSF

*Communicate with 3rd ventriclethrough??interventricular foramina(2 innumber).

* Separated from each otherby??SEPTUM PELLUCIDUM.


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Septum Pellucidum


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Third Ventricle

Located within diencephalon

At midline between 2 masses ofthalamus

Boundaries:Lat. Walls: 2 masses of

thalamus

floor: hypothalamus

Communicates with 4th ventriclevia ?? cerebral aqueduct


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4th Ventricle

Located between:

brain stem & cerebellum

Contains 3 foramina in its

roof (Why??)- 2 laterally foramen ofluschka- foramen of Magendie**** To drain the CSF frominside the brain intosubarachnoid space betweenthe meninges
http://en.wikipedia.org/wiki/Median_aperturehttp://en.wikipedia.org/wiki/Median_aperturehttp://en.wikipedia.org/wiki/Median_aperture


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Clinical: hydrocephalus

(Hydro: water, Cephalus: head)Excess CSF in the ventricles leading enlargement of the head

Causes:

1. overproduction

2. obstruction of CSF flow

3. interference with CSF absorption

Results in infants:

the head in size


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Arachnoid Granulations


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Arteries of The Brain

The main arteries of the Brain

Include:

2 ICA

2 Vertebral a.

Read Your Textbook for Detailed Anatomy of arterial bld. supply to the

brain


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Internal Carotid ArteryRead Your Text

5 branches

1. Ophthalmic a.:

to orbit, through? optic canal

2. Ant. Cerebral a.:

runs in longitudinal fissure

medial surface of cerebrum

until ?? parieto-occipital sulcus

3. Middle cerebral a.:

largest branch of ICA

runs in lat. Sulcus

most lat. Surface of cerebrum

4. Post. Communicating a.

5. Choroidal a.


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Medial Surface

Lateral Surface


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Vertebral Arteries

The 2 vertebral a. join at lower border of Pons to form:

Basilar artery

V. a. branches: (4)

post. Meningeal a. (dura mater )

ant. & post. Spinal a. (spinal cord)

post. Inf. Cerebellar a. (cerbulum)

medullary a. (medulla oblongata )


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Basilar Artery

4 branchesarteries to cerebellum

Labyrinthine artery

Pontine a.

Post. Cerebral a.:

turns backward at midbrin

supply:occipital lobe

inf. Part of temporal lobe

& the medial part of temporallobe


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Circulus ArteriosusCircle of Willis

Anastomosis between branchesof 2 ICA & 2 vertebral a.

Consists of:

ant. Communicating a.

ant. Cerebral a.

ICA

Post. Communicating a

post. Cerebral a.

basilar a.


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