diencephalon
DESCRIPTION
TRANSCRIPT
DIENCEPHALON
DEVELOPMENT
ANATOMY OF DIENCEPHALON
• CONSISTS OF THE THIRD VENTRICLE AND THE STRUCTURES THAT FORM ITS BOUNDARIES
• EXTENT• INTERVENTRICULAR FORAMEN--- ANTERIORLY
TO• THE POINT WHERE THE 3rd VENTRICLE
BECOMES CONTINUOUS WITH THE AQUEDUCT---POSTERIORLY
ANATOMY OF DIENCEPHLON
• INFERIOR SURFACE
• ONLY EXPOSED AREA• INCLUDES FROM ANTERIOR TO POSTERIOR----• OPTIC CHIASMA &OPTIC TRACT• INFUNDIBULUM WITH TUBER CINEREUM• MAMMILARY BODIES
ANATOMY OF DIENCEPHALON
• SUPRIOR SURFACE
• FORMED BY THE ROOF OF 3rd VENTRICLE• CONCEALED BY FORNIX---A THICK BAND OF
FIBRES----ARISES IN THE HIPPOCAMPUS---ARCHES OVER THE THALAMUS TO JOIN THE MAMMILARY BODIES
ANATOMY OF DIENCEPHALON
• MEDIAL SURFACE• FORMED BY—• THALAMUS AND• HYPOTHALAMUS• LATERAL SURFACE• BOUNDED BY• INTERNAL CAPSULE
DEVELOPMENT OF DIENCEPHALON
• DEVELOPS FROM FOREBRAIN VESICLE• ROOF AND FLOOR PLATES REMAIN THIN• LATERAL WALLS BECOME THICK• WITH THE CLOSURE OF THE ROSTRAL
NEUROPORE A DIVERTICULUM------THE OPTIC VESICLE APPEARS ON EACH SIDE OF THE FOREBRAIN
• PART OF BRAIN CAUDAL TO OPTIC VESICLE FORMS THE DIENCEPHALON
DEVELOPMENT OF DIENCEPHALON
• RETINA AND OPTIC DISK DERIVED FROM OPTIC VESICLE AND STALK
• CAVITY OF DIENCEPHALON FORMS THE GREATER PART OF 3rd VENTRICLE
• SMALL PART OF THE CAVITY OF THE TELENCEPHALON ALSO CONTRIBUTES TO THE FORMATION OF 3rd VENTRICLE
DEVELOPMENT OF DIENCEPHALIN
• DIENCEPHALON CONSISTS OF---• A ROOF PLATE AND• TWO ALAR PLATES• ROOF SHOWS A SMALL DIVERTICULUM
IMMEDIATELY ANTERIOR TO MIDBRAIN WHICH WILL FORM THE PINEAL BODY
• REMAINDER OF THE ROOF WILL FORM THE CHOROID PLEXUS OF 3rd VENTRICLE
DEVELOPMENT OF DIENCEPHALON
• THREE SWELLINGS DEVELOP IN THE LATERAL WALL OF 3rd VENTRICLE WHICH LATER BECOME THE---
• 1 EPITHALAMUS• 2 THALAMUS• 3 HYPOTHALAMUS
DEVELOPMENT OF DIENCEPHALON
• THALAMUS SEPARATED FROM EPITHALAMUS BY EPITHALAMIC SULCUS
• THALAMUS SEPARATED FROM HYPOTHALAMUS BY HYPOTHALAMIC SULCUS
• PINEAL BODY• INITIALLY APPEARS AS AN EPITHELIAL THICKENING IN
MIDLINE• BY 7th WEEK BEGINS TO EVAGINATE• BECOMES A SOLID ORGAN ON THE ROOF OF
MESENCEPHALON
DEVELOPMENT OF DIENCEPHALON
• THALAMUS• ARISES AS A THICKENING OF ALAR PLATE ON THE
LATERAL WALLS OF 3rd VENTRICLE• DEVELOPS RAPIDLY ON EACH SIDE• BULGES INTO THE CAVITY OF 3rd VENTRICLE REDUCING
IT TO A NARROW CLEFT• IN 70 % OF BRAINS THE THALAMI MEET AND FUSE IN
THE MIDLINE FORMING A BRIDGE OF GRAY MATER ACROSS THE 3rd VENTRICLE---THE INTERTHALAMIC ADHESION OR MASSA INTERMEDIA
DEVELOPMENT OF DIENCEPHALON
• MEDIAL GENICULATE BODY AND• LATERAL GENICULATE BODY
• DEVELOP AS SOLID BUDS---- THE METATHALAMUS
DEVELOPMENT OF DIENCEPHALON
• HYPOTHALAMUS• ARISES BY PROLIFERATION OF NEUROBLASTS
IN LOWER PART OF ALAR PLATE ON EACH SIDE OF 3rd VENTRICLE VENTRAL TO HYPOTHALAMIC SULCUS
• A NUMBER OF NUCLEI CONCERNED WITH ENDOCRINE ACTIVITIES AND HOMEOSTASIS DEVELOP
DEVELOPMENT OF DIENCEPHALON
• MAMILLARY BODIES
• A PAIR OF NUCLEI
• FORM PEA-SIZED SWELLINGS ON THE VENTRAL SURFACE OF HYPOTHALAMUS
DEVELOPMENT OF DIENCEPHALON
• THIRD VENTRICLE• DEVELOPS FROM THE---
• 1 CAVITY OF DIENCEPHALON AND• 2 SMALL PART OF THE CAVITY OF
TELENCEPHALON
DEVELOPMENT OF DIENCEPHALON
• THIRD VENTRICLE [ CONTD ]
• ROOF PLATE OF DIENCEPHALON IS THIN MADE UP OF A SINGLE LAYER OF EPENDYMA COVERED BY VASCULAR MESENCHYME FORMING THE CHOROID PLEXUS
• ROOF EXTENDS FROM THE INTERVENTRICULAR FORAMEN TO HABENULAR COMMISSURE
DEVELOPMENT OF DIENCEPHALON
• THIRD VENTRICLE [ CONTD ]• ANTERIOR WALL• FORMED BY THE LAMINA TERMINALIS • LATERAL WALL• FORMED BY THE THALAMI • FLOOR• EXTENDS FROM OPTIC RECESS ON THE SUPERIOR
SURFACE OF OPTIC CHIASMA INTO THE INFUNDIBULAR RECESS AND THEN ABOVE MAMILLARY BODY TO THE AQUEDUCT
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