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Copyright © 2010 Pearson Education, Inc.
The Central Nervous System
Copyright © 2010 Pearson Education, Inc. Figure 7.12
MidbrainCerebellumPonsMedulla oblongata
Spinal cord
Cerebral hemisphere
Outline of diencephalon
(a) Week 13
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Right cerebral
hemisphere
Left cerebralhemisphere
Longitudinalfissure
Posterior
Anterior• Surface markings
• Gyri = ridges
• Sulci = shallow grooves
• Fissures = deep grooves
• Lobes
• Frontal
• Parietal
• Temporal
• Occipital
Features of the Cerebrum
Copyright © 2010 Pearson Education, Inc. Figure 7.13
Postcentralgyrus
Centralsulcus
Precentralgyrus
Frontallobe
(a)
Parietal lobe
Occipital lobeTemporal lobe
Cerebellum
Cortex (gray matter)
FissureGyrus
SulcusWhite matter
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Cerebellum
Diencephalon
Cerebrum
(b) Adult Brain
Brain stem
The Principal Parts of the Adult BrainThe Principal Parts of the Adult Brain
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Cerebral Cortex
• Thin superficial layer of gray matter
• Deeper white matter composed of fiber tracts carrying impulses to or from cortex
• Corpus callosum- connects cerebral hemispheres
Diencephalon
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• Enclosed by cerebral hemispheres
• Major structures of diencephalon:– Thalamus– Hypothalamus– Epithalamus
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Thalamus
• Relay station for sensory impulses passing up to sensory cortex
• Encloses the 3rd ventricle
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Hypothalamus• Below thalamus
• Floor of diencephalon
• Pituitary hangs from hypothalamus
• Important autonomic nervous center for:
• Body temperature
• Metabolism
• Water balance
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Epithalamus
• Forms roof of 3rd ventricle
• Pineal body- part of endocrine system
• Choroid plexus – capillary beds which form CSF
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ThalamusHypothalamus Epithalamus
Pituitary Gland
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The Brain Stem
• Midbrain
• Pons
• Medulla Oblongata
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The Midbrain• Superior portion of brainstem
• Cerebral aqueduct passes through to connect 3rd ventricle above and 4th ventricle below
• Anteriorly composed of tracts called cerebral peduncles that
• Convey ascending & descending impulses
• Dorsally placed are corpora quadrigemina that are
• Reflex centers for hearing, vision
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Coropora Quadrigemina
Cerebral Peduncles
Cerebral Aqueduct
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The Pons• Rounded structure just
below midbrain
• Mostly fiber tracts that bridge areas of brain
• Contains nuclei involved in the control of breathing
Pons
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Medulla Oblongata• Inferior portion of brain stem
• Many important fiber tracts
• Contains nuclei that regulate vital visceral activities
• Heart rate
• Blood pressure
• Breathing
• Swallowing, etc.
Medulla Oblongata
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Cerebellum• Functions:
• Precise timing for skeletal muscle activity
• Controls balance & equilibrium
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Meninges• Functions:
• Cover and protect the CNS
• Contain cerebrospinal fluid (CSF)
• Form partitions in the skull
• Three layers
• Dura mater
• Arachnoid mater
• Pia mater
Copyright © 2010 Pearson Education, Inc. Figure 7.16
Skin of scalpPeriosteum
Pia materArachnoid mater
Dura mater InnerOuter
Bone of skull
Subduralspace
Subarachnoidspace
Superiorsagittal sinus
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Meninges
• Dura Mater (Strongest, Outer layer)
• Two layers (fibrous CT); separate to form dural sinuses
• Dural septa – inward folds of dura mater
• Falx cerebri—in longitudinal fissure
• Falx cerebelli— separates cerebellum in half
• Tentorium cerebelli—horizontal; separates cerebellum and cerebrum
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Falx cerebri
Crista galliOf ethmoid bone
Falxcerebelli
(a) Dural septa
Tentoriumcerebelli
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• Arachnoid Mater- Middle layer
• Weblike
• Contains CSF & blood vessels
• Arachnoid villi extend into dural sinus; allow CSF reabsorption
• Pia Mater -Innermost layer
• Delicate vascularized CT that clings tightly to the brain
Meninges
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Ventricles of the Brain
• Connected to one another and to central canal of spinal cord
• Two C-shaped lateral ventricles in the cerebral hemispheres
• Third ventricle in diencephalon
• Fourth ventricle is dorsal to pons
Copyright © 2010 Pearson Education, Inc. Figure 7.17
Interventricularforamen
Lateralaperture
(b) Left lateral view
Lateral ventricle
Third ventricle
Cerebral aqueduct
(a) Anterior view
Fourth ventricleCentral canal
