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Telencephalon

Prosencephalon Optic vesicle Diencephalon

Mesencephalon

Metencephalon Rhombencephalon Myelencephalon

Spinal cord

(a) 4 weeks (b) 5 weeks

Telencephalon Forebrain Diencephalon

Mesencephalon Midbrain

Pons Metencephalon Cerebellum Hindbrain Myelencephalon (medulla oblongata)

Spinal cord

(c) Fully developed 3

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Cerebral Rostral Caudal hemispheres

Central sulcus

Gyri Cerebrum Frontal lobe Lateral sulcus

Central sulcus Temporal lobe Cerebellum

Parietal lobe Brainstem Occipital lobe Spinal cord Longitudinal fissure (a) Superior view (b) Lateral view

Precentral gyrus Central sulcus Postcentral gyrus

Frontal lobe Parietal lobe

Arachnoid mater Insula

Temporal lobe Occipital lobe

Cerebellum

Blood vessels

Medulla oblongata (c) Lateral view 5 c: © The McGraw-Hill Companies, Inc./Rebecca Gray, photographer/Don Kincaid, dissections

6 7

8 9

10 11

12 13

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Skull Dura mater: Periosteal layer Subdural space Meningeal layer Subarachnoid Arachnoid villus space

Arachnoid mater Superior sagittal Blood vessel sinus Falx cerebri Pia mater (in longitudinal fissure only) Brain: Gray matter White matter

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Caudal Rostral

Lateral ventricles

Interventricular foramen Third ventricle Cerebral aqueduct Fourth ventricle Lateral aperture Median aperture

Central canal

(a) Lateral view

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Cerebrum Lateral ventricle Interventricular foramen Third ventricle Cerebral aqueduct Fourth ventricle Lateral aperture Median aperture

(b) Anterior view

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Arachnoid villus 8

Superior sagittal sinus

Arachnoid mater

1 CSF is secreted by choroid plexus in Subarachnoid each lateral ventricle. space

Dura mater 1 2 CSF flows through Interventricular foramina into third ventricle. 2 Choroid plexus

3 Third ventricle 3 Choroid plexus in third ventricle adds more CSF.

7 4 Cerebral 4 CSF flows down cerebral aqueduct aqueduct to fourth ventricle.

Lateralaper ture

5 Choroid plexus in fourth ventricle adds more CSF. Fourth ventricle

6 5 6 CSF flows out two lateral apertures and one median aperture.

Median aperture 7 CSF fills subarachnoid space and bathes external surfaces of brain and spinal cord. 7

8 At arachnoid villi, CSF is reabsorbed into venous blood of dural venous sinuses. Centralcanal of spinal cord

Subarachnoid space of spinal cord 18 19

20 21

22 23

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26 27

28 29

30 31