hubs191 lecture material
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HUBS191 Lecture Material This pre-lecture material is to help you
prepare for the lecture and to assist your note-taking within the lecture,
it is NOT a substitute for the lecture ! !
Please note that although every effort is made to ensure this pre-lecture material corresponds to the live-lecture there may be differences / additions.
CJASONI, 2017 HUBS191
Dr Christine Jasoni Department of Anatomy
Theme 2: Integrating and coordinating roles of the nervous system
Lecture 19: Support and protection of the nervous system
30 March 2017
HUBS 191 Human Movement and Sensation
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Lecture 19: Learning objectives
After this lecture and associated study you should know and understand: • The bones of the cranium and facial skeleton and how they are joined • The meninges and their structural and functional properties in both the brain and spinal cord • The ventricular system and flow of cerebrospinal fluid (CSF)
CJASONI, 2017 HUBS191
•! Skull - 28 bones •! Cranium (=8) •! Face (=14) •! Ear bones (=6)
•! Vertebral column - 26 bones •! Cervical vertebrae (7) •! Thoracic vertebrae (12) •! Lumbar vertebrae (5) •! Sacrum (5 fused vertebrae) •! Coccygeal (4/5 fused vert)
Support provided by the axial skeleton
See also: Patton and Thibodeau 8th ed Fig 9-1 (7th ed Fig 8-1)
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Bones of the skull
Facial skeleton
Cranial vault (cranium)
Modified from Patton and Thibodeau 8th ed, Fig 9-3 (7th ed, Fig 8-3)
Skull = cranial vault (or cranium) + facial skeleton
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Bones of the skull: I. The cranium
• Cranium composed of 8 bones ~ 7 visible on lateral sides ~1 visible internally = Ethmoid bone, not shown
Lateral view (from the side)
Modified from Patton and Thibodeau 8th ed, Fig 9-3 (7th ed, Fig 8-3)
Frontal (1) Parietal (2)
Temporal (2) Sphenoid (1)
Occipital (1)
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Bones of the cranium have joints between them called sutures
Coronal suture
• Frontal - Parietal Lambdoidal suture
• Occipital - Parietal
Squamous suture
• Temporal - Parietal Modified from Patton and Thibodeau 8th ed, Fig 9-3 (7th ed, Fig 8-3)
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Suture means a row of stitches
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frontal
parietal
Modified from Patton and Thibodeau 8th ed, Fig 9-3 (7th ed, Fig 8-3)
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See also: Patton and Thibodeau, 8th ed, Fig 9-11 (7th ed, Fig 8-11)
The skull at birth – Sutures are not yet joined
• Gaps between sutures are called fontanelles • Allow the brain to grow after birth
- Premature closure can block brain growth ! cognitive impairment
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Relationship between the brain and the cranium – Anterior view
http://filetraffic.eu/s/the%20human%20head%20skull SMART image base, with approval (for anterior brain)
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Bones of the cranium: II. Facial skeleton
Facial skeleton composed of 14 bones SEVEN (7) external: • Zygomatic (2)
Zygomatic
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Bones of the cranium: II. Facial skeleton
Zygomatic
Facial skeleton composed of 14 bones SEVEN (7) external: • Zygomatic (2) • Maxillary (2)
Maxillary
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Bones of the cranium: II. Facial skeleton
Zygomatic
Facial skeleton composed of 14 bones SEVEN (7) external: • Zygomatic (2) • Maxillary (2) • Mandible (1)
Mandible
Maxillary
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Bones of the cranium: II. Facial skeleton
Zygomatic
Facial skeleton composed of 14 bones SEVEN (7) external: • Zygomatic (2) • Maxillary (2) • Mandible (1) • Nasal (2) SEVEN (7) internal (not shown): *And you don’t need to know them!
Mandible
Nasal
Maxillary
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Meninges
Scalp
Skull
Meninges
Skull
Meninges - Protective covering for the brain
Equivalent to Patton and Thibodeau, 8th ed, Fig 14-2 (7th ed, Fig 13-2)
(from Greek Meninx = membrane) Meninges - Protective covering for the brain
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Meninges: Three layers of protective tissue
•! Meninges means membrane
•! Between the skull and the brain
Grey matter!
White matter!
MENINGES
Skull"
Scalp"
Dura mater 1
Arachnoid 2
Pia mater 3
From Marieb: Human Anatomy and Physiology, 8th ed, 2010. See also: Patton and Thibodeau, 8th ed, Fig 14-2 (7th ed, Fig13-2)
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Dura mater = ‘Tough mother’ Dura like Durable, Mater like Maternal
• Outer-most layer of meninges • Dense and fibrous – tough • Two layers • Inner layer forms the dural reflections • Space between the layers forms venous sinuses
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Features of Dura mater: I. Dural reflections • Formed from inner layer of dura mater • Separate major divisions of brain • Three of them
Outer layer Inner layer
From Marieb: Human Anatomy and Physiology, 8th ed, 2010. See also: Patton and Thibodeau, 8th ed, Fig 14-2 (7th ed, Fig13-2)
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Modified from: Nolte J, The Human Brain , ed. 2, 1988, fig. 3.3, CV Mosby pub.
Dural reflections
Three of them: 1." Falx cerebri
-! separates cerebral hemispheres -! median plane
2. Falx cerebelli - separates cerebellar hemispheres - median plane
3. Tentorium cerebelli
- separates the cerebrum from the cerebellum - horizontal plane
• Inward extensions of the dura mater
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Falx means sickle-shaped
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Features of Dura mater: II. Venous sinus
Outer layer Inner layer
• Form between outer and inner layers • Venous drainage from the brain
From Marieb: Human Anatomy and Physiology, 8th ed, 2010. See also: Patton and Thibodeau, 8th ed, Fig 14-2 (7th ed, Fig13-2)
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Arachnoid – A layer beneath the Dura mater
See also: Patton and Thibodeau, 8th ed, Fig 14-2 (7th ed, Fig 13-2)
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Arachnoid mater = spider like
• Layer beneath the dura mater • Contains blood vessels • Does not extend into sulci (‘valleys’)
Arachnoid
Arachnoid
From Marieb: Human Anatomy and Physiology, 8th ed, 2010. See also: Patton and Thibodeau, 8th ed, Fig 14-2 (7th ed, Fig13-2)
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Subarachnoid space
Arachnoid
Subrachnoid space
Pia mater
Filled with cerebrospinal fluid (CSF)
• Between the arachnoid and the pia mater • Filled with cerebrospinal fluid (CSF)
http://www.freefoto.com
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Arachnoid granulations (or villi)
• Perforate the dura • Transport “old” CSF from subarachnoid space into venus sinus
Arachnoid
From Marieb: Human Anatomy and Physiology, 8th ed, 2010. See also: Patton and Thibodeau, 8th ed, Fig 14-2 (7th ed, Fig13-2)
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Adapted from: Marieb: Human Anatomy and Physiology
Pia mater = delicate mother • Transparent and delicate • Blood vessels in arachnoid sit on top of pia mater • Adheres to brain and follows gyri and sulci
a sulcus Pia mater
See also: Patton and Thibodeau, 8th ed, Fig 14-2 (7th ed, Fig13-2)
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The meninges of the spinal cord
Patton and Thibodeau, 8th ed, Fig 14-3 (7th ed, Fig 13-3)
*Q: Which side of the spinal cord is facing you?
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The ventricular system
Anterior (Head-on) view
Patton and Thibodeau, 8th ed, Fig 14-4 (7th ed, Fig. 13-4)
•! Network of interconnected spaces within the brain
•! Filled with cerebrospinal fluid (CSF), which nourishes and protects the brain
•! CSF is produced by the choroid plexus, which lines the ventricles
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The ventricular system
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Patton and Thibodeau, 8th ed, Fig 14-4 (7th ed, Fig 13-4)
Pons
Third ventricle
Interventricular foramen
Anterior horn of lateral ventricle
Central canal of spinal cord
Cerebellum
Fourth ventricle
Cerebral aqueduct
Posterior horn of lateral ventricle
Cerebral Hemisphere
Inferior horn of lateral ventricle
Anterior Posterior
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C Jasoni, 2016
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Patton and Thibodeau, 8th ed, Fig 14-5 (7th ed, Fig 13-5)
Choroid plexus
Subarachnoid space Arachnoid villus
Circulation of the CerebroSpinal Fluid (CSF) 29
•! Bathes and cushions the brain •! Is generated in the ventricles by
choroid plexus
•! Circulates through ventricles and subarachnoid space of the brain and spinal cord Route: Lateral ventricle ! 3rd ventricle ! cerebral aqueduct ! 4th ventricle ! subarachnoid space
•! Enters venous blood circulation within the venous sinuses via arachnoid villi/granulations
•! Is sampled to determine if meningitis is present
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From: Marieb: Human Anatomy and Physiology
When it goes wrong: Hydrocephalus
•! Caused by abnormal accumulation of CSF in the ventricles of the brain
•! Leads to increased intracranial pressure inside the skull,
•! Progressive enlargement of the head,
•! Other symptoms include •! convulsion, •! tunnel vision, •! mental disability.
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Lecture 19: Post-lecture quiz • Which of these is not a layer of meninges
(a) dura mater; (b) epineurium; (c) pia mater; (d) arachnoid
• Which of the following bones is part of the facial skeleton
(a) parietal bone; (b) occipital bone; (c) mandible; (d) spinous process
• Which layer of the meninges contains circulating cerebrospinal fluid?
(a) arachnoid; (b) dura mater; (c) perineurium; (d) choroid plexus
• Which structure is important for removal of old/used CSF
(a) choroid plexus; (b) arachnoid granulations; (c) dural reflections; (d) pia mater
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