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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 that

connect 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 neurons

located 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 ½ of 

neurons

Location:

post. Cranial fossa

beneath tentorium cerebelli

Fxn.:

coordination of muscle tone &movements on same side of body

Regulates posture & balance

*Ataxia: ?? Due to damage tocerebellum

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Meningeal Reflections

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Ventricular System of The Brain

“Brain Chambers” 

Consists of:

2 lat. Ventricles

3rd ventricle

4th ventricle

* Contain choroid plexuses

CSF

Choroid 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 with

CSF

*Communicate with 3rd ventricle

through??

interventricular foramina (2 in

number). 

* Separated from each other by??

SEPTUM PELLUCIDUM. 

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Septum Pellucidum

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Third Ventricle

Located within diencephalon

At midline between 2 masses of 

thalamus

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 of

luschka”

- foramen of Magendie  **** To drain the CSF from

inside the brain into

subarachnoid space between

the meninges 

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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 temporal

lobe

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Circulus Arteriosus

“Circle of Willis” 

Anastomosis between branches

of 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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