AIM
SWBAT discuss the meningeal layers of the central nervous system and
the formation and circulation of cerebrospinal fluid.
.
Criteria for Success
[ ] I can list and describe the structure of meninges.
[ ] I can list and describe the four ventricles.
[ ] I can identify the location of the secretion of cerebrospinal fluid.
[ ] I can describe the location and function cerebrospinal fluid.
WHAT IS THIS?
SEM of a single neuron of the human cerebral cortex – the
outer gray matter of the brain.
3
Introduction
• The central nervous system (CNS) consists of the brain
and spinal cord.
• The brainstem connects the brain to the spinal cord.
• Communication to the peripheral nervous system (PNS)
is by way of the spinal cord.
4
Meninges
• The meninges
• Membranes of CNS
• Protect the CNS
• Three (3) layers:
• Dura mater
• “Tough mother”
• Venous sinuses
• Falx
• Arachnoid mater
• “Spiderweb-like”
• Space contains
cerebrospinal fluid
(CSF)
• Pia mater
• “Faithful mother”
• Encapsulates blood
vessels
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Scalp
Cranium
Cerebrum
Tentorium
cerebelli
Cerebellum
Vertebra
Spinal cord
Meninges
(a)
(b)
Skin
Subcutaneous tissue
Bone of skull
Dural sinus
Arachnoid
granulation
Dura mater
Arachnoid
Meninges
mater
Pia mater
Subarachnoid space
Falx cerebri
Gray matter
White matter
Cerebrum
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Meninges
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876
Meninges of the Spinal Cord
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Spinal cord
Ventral root
Dorsal root
Spinal nerve
Dorsal root
ganglion
Subarachnoid
space
Pia mater
Arachnoid mater
Epidural space
Dura mater
Dorsal root
Dorsal branch
(dorsal ramus)
Spinal
nerve
Ventral branch
(ventral ramus)
Dorsal root
ganglion
Spinal cord
Ventral root
Epidural
space
Thoracic
vertebra
(a)
(b)
Body of
vertebra
7
Ventricles
and Cerebrospinal Fluid
• There are four (4) ventricles
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• The ventricles are interconnected
cavities within cerebral hemispheres and Interventricular
foramen
brain stem
• The ventricles are continuous with the
central canal of the spinal cord
Lateral ventricle
Third ventricle
Cerebral
aqueduct
Fourth ventricle
To central canal
of spinal cord
• They are filled with cerebrospinal fluid
(CSF)
(a)
Interventricular
foramen
Lateral
ventricle
Third ventricle
Cerebral
aqueduct
Fourth
ventricle
(b)
To central canal
of spinal cord
8
Ventricles
and Cerebrospinal Fluid
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• The four (4) ventricles are:
• Lateral ventricles (2)
• Known as the first and
second ventricles
• Cerebral hemisphere
Lateral ventricle
Interventricular
foramen
Third ventricle
Cerebral
aqueduct
• Third ventricle
• Midline of the brain
beneath corpus callosum
• Communicates with lateral
ventricles through
interventricular foramen
Fourth ventricle
To central canal
of spinal cord
(a)
Interventricular
foramen
Lateral
ventricle
Third ventricle
• Fourth ventricle
• Brainstem
• Cerebral Aqueduct it
connects to third ventrical
Cerebral
aqueduct
Fourth
ventricle
(b)
To central canal
of spinal cord
9
Cerebrospinal Fluid
• Secreted by the choroid plexus
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Arachnoid
granulations
• Circulates in ventricles, central
Choroid plexuses
canal of spinal cord, and the
of third ventricle
subarachnoid space
Third ventricle
Cerebral aqueduct
Fourth ventricle
• Completely surrounds the brain
and spinal cord
• Excess or wasted CSF is
absorbed by the arachnoid villi
that project from the
subarachnoid space into the
blood-filled dural sinuses
Blood-filled
dural sinus
Pia mater
Subarachnoid space
Arachnoid mater
Dura mater
Choroid plexus of
fourth ventricle
Central canal of spinal cord
Pia mater
Subarachnoid space
Filum terminale
Arachnoid mater
Dura mater
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Cerebrospinal Fluid
• Clear, watery fluid similar to
blood plasma
• Volume is only about 120 ml
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Arachnoid
granulations
Blood-filled
dural sinus
Choroid plexuses
of third ventricle
Pia mater
• About 500 ml secreted per day
Third ventricle
Cerebral aqueduct
Fourth ventricle
Subarachnoid space
Arachnoid mater
Dura mater
•Most secreted in the lateral
ventricles
• Nutritive and protective
Choroid plexus of
fourth ventricle
Central canal of spinal cord
Pia mater
Subarachnoid space
Filum terminale
Arachnoid mater
Dura mater
• Helps maintain stable ion
concentrations in the CNS
11
CSF Flow
Please note that due to differing
operating systems, some animations
will not appear until the presentation is
viewed in Presentation Mode (Slide
Show view). You may see blank slides
in the “Normal” or “Slide Sorter” views.
All animations will appear after viewing
in Presentation Mode and playing each
animation. Most animations will require
the latest version of the Flash Player,
which is available at
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17