the cerebrum i
TRANSCRIPT
The cerebrum I
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•The diencephalon
• The diencephalon
• Cerebral
hemispheres
• Internal capsule
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The white matter
•It’s situated in the anterior & middle
cranial fossae
•Cerebrum is divided into 2 parts
1)Diencephalon : Forms the central
core
2)Telencephalon : Forms cerebral
hemispheres
The cerebrum
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The white matter
Diencephalon•It’s a midline structure with symmetrical right & left halves
•It can be divided into 4 major parts :
1. Thalamus 2. Subthalamus 3. Epithalamus 4. Hypothalamus
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The white matter
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The white matter 3rd ventricle
•Situated between the 2 thalami
•Communicates anteriorly with the lateral ventricles
through the inter ventricular foramina (Foramen of
Monro)
•Communicates posteriorly with the 4th ventricle
trough the cerebral aqueduct
•It’s walls are lined by ependyma
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The white matter
•Cerebral hemispheres (Telencephalon)•Largest part of the brain
•2 hemispheres are separated by a deep midline fissure : The
longitudinal cerebral fissure
•Corpus callosum connects the hemispheres across the midline
•Tentorium cerebelli separates the cerebral hemispheres from the
cerebellum
•To increase the surface area of the cerebral cortex, each hemisphere
has formed folds (Gyri) & gyri are separated by sulci (Fissures)
•Each hemisphere is divided into 4 lobes : Frontal, parietal,
temporal & occipital (Named according to the cranial bones under
which they lie)
The white matter The main sulci & Gyri
Lateral view of the left cerebral hemisphere
The white matter The main sulci & Gyri
Medial view of the right cerebral hemisphere
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The white matter The structures situated interior to the cerebral hemispheres:
•Lateral ventricles
•Basal nuclei
•White matter & nerve fibers
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The white matter •Basal ganglia
•It’s a collection of grey masses in the white matter of
the hemispheres
•There are 3 main parts
1)Corpus striatum : Divided by the
internal capsule into Caudate & Lentiform nucleus
2)Amygdaloid nucleus: Situated in the temporal
lobe
3)Claustrum
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The white matter •White matter of the cerebral hemispheres
•It’s composed of myelinated nerve fibers
•The nerve fibers are classified into 3 groups
1)Commissural fibers
2)Association fibers
3)Projection fibers
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The white matter
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The white matter Internal capsule & its nerve fiber arrangement
Relationships between internal
capsule, basal ganglia, and
thalamus in horizontal section.
Notice that descending motor
fibers for the face, arm, and leg (F,
A, L) run in front of ascending
sensory fibers
(f, a, l) in the posterior limb of the
internal capsule.
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