the nervous system. protection of the central nervous system scalp and skin skull and vertebral...
TRANSCRIPT
![Page 1: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/1.jpg)
The Nervous System
![Page 2: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/2.jpg)
Protection of the Central Nervous System
• Scalp and skin
• Skull and vertebral column
• Meninges
• Cerebrospinal fluid (CSF)
• Blood-brain barrier
![Page 3: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/3.jpg)
Protection of the Central Nervous System
Figure 7.17a
![Page 4: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/4.jpg)
Meninges
• Dura mater– Double-layered external covering
• Periosteum—attached to inner surface of the skull• Meningeal layer—outer covering of the brain
– Folds inward in several areas
![Page 5: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/5.jpg)
Meninges
• Arachnoid layer– Middle layer– Web-like
• Pia mater– Internal layer– Clings to the surface of the brain
![Page 6: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/6.jpg)
Meninges
Figure 7.17b
![Page 7: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/7.jpg)
Cerebrospinal Fluid (CSF)
• Similar to blood plasma composition
• Formed by the choroid plexus
• Forms a watery cushion to protect the brain
• Circulated in arachnoid space, ventricles, and central canal of the spinal cord
![Page 8: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/8.jpg)
Figure 7.18a–b
Ventricles and Location of the Cerebrospinal Fluid
![Page 9: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/9.jpg)
Ventricles and Location of the Cerebrospinal Fluid
Figure 7.18c
![Page 10: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/10.jpg)
Hydrocephalus in a Newborn
• Hydrocephalus– CSF accumulates and exerts pressure on the
brain if not allowed to drain
Figure 7.19
![Page 11: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/11.jpg)
Blood-Brain Barrier• Includes the least permeable capillaries of the
body• Excludes many potentially harmful substances• Useless as a barrier against some substances
– Fats and fat soluble molecules– Respiratory gases– Alcohol– Nicotine– Anesthesia
![Page 12: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/12.jpg)
Traumatic Brain Injuries
• Concussion– Slight brain injury– No permanent brain damage
• Contusion– Nervous tissue destruction occurs– Nervous tissue does not regenerate
• Cerebral edema– Swelling from the inflammatory response– May compress and kill brain tissue
![Page 13: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/13.jpg)
Cerebrovascular Accident (CVA)
• Commonly called a stroke
• The result of a ruptured blood vessel supplying a region of the brain
• Brain tissue supplied with oxygen from that blood source dies
• Loss of some functions or death may result
![Page 14: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/14.jpg)
Alzheimer’s Disease
• Progressive degenerative brain disease• Mostly seen in the elderly, but may begin in
middle age• Structural changes in the brain include
abnormal protein deposits and twisted fibers within neurons
• Victims experience memory loss, irritability, confusion, and ultimately, hallucinations and death
![Page 15: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/15.jpg)
Spinal Cord
• Extends from the foramen magnum of the skull to the first or second lumbar vertebra
• 31 pairs of spinal nerves arise from the spinal cord
• Cauda equina is a collection of spinal nerves at the inferior end
![Page 16: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/16.jpg)
Spinal Cord Anatomy
Figure 7.20 (1 of 2)
![Page 17: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/17.jpg)
Spinal Cord Anatomy
Figure 7.20 (2 of 2)
![Page 18: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/18.jpg)
Spinal Cord Anatomy
• Internal gray matter is mostly cell bodies– Dorsal (posterior) horns– Anterior (ventral) horns – Gray matter surrounds the central canal
• Central canal is filled with cerebrospinal fluid
• Exterior white mater—conduction tracts– Dorsal, lateral, ventral columns
![Page 19: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/19.jpg)
Spinal Cord Anatomy
Figure 7.21
![Page 20: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/20.jpg)
Spinal Cord Anatomy
• Meninges cover the spinal cord
• Spinal nerves leave at the level of each vertebrae– Dorsal root
• Associated with the dorsal root ganglia—collections of cell bodies outside the central nervous system
– Ventral root• Contains axons
![Page 21: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/21.jpg)
Pathways Between Brain and Spinal Cord
Figure 7.22
![Page 22: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/22.jpg)
Peripheral Nervous System (PNS)
• Nerves and ganglia outside the central nervous system
• Nerve = bundle of neuron fibers
• Neuron fibers are bundled by connective tissue
![Page 23: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/23.jpg)
PNS: Structure of a Nerve
• Endoneurium surrounds each fiber
• Groups of fibers are bound into fascicles by perineurium
• Fascicles are bound together by epineurium
![Page 24: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/24.jpg)
PNS: Structure of a Nerve
Figure 7.23
![Page 25: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/25.jpg)
PNS: Classification of Nerves
• Mixed nerves– Both sensory and motor fibers
• Sensory (afferent) nerves– Carry impulses toward the CNS
• Motor (efferent) nerves– Carry impulses away from the CNS
![Page 26: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/26.jpg)
PNS: Cranial Nerves
• 12 pairs of nerves that mostly serve the head and neck
• Only the pair of vagus nerves extend to thoracic and abdominal cavities
• Most are mixed nerves, but three are sensory only
![Page 27: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/27.jpg)
PNS: Cranial Nerves
• I Olfactory nerve—sensory for smell
• II Optic nerve—sensory for vision
• III Oculomotor nerve—motor fibers to eye muscles
• IV Trochlear—motor fiber to eye muscles
![Page 28: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/28.jpg)
PNS: Cranial Nerves
• V Trigeminal nerve—sensory for the face; motor fibers to chewing muscles
• VI Abducens nerve—motor fibers to eye muscles
• VII Facial nerve—sensory for taste; motor fibers to the face
• VIII Vestibulocochlear nerve—sensory for balance and hearing
![Page 29: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/29.jpg)
PNS: Cranial Nerves
• IX Glossopharyngeal nerve—sensory for taste; motor fibers to the pharynx
• X Vagus nerves—sensory and motor fibers for pharynx, larynx, and viscera
• XI Accessory nerve—motor fibers to neck and upper back
• XII Hypoglossal nerve—motor fibers to tongue
![Page 30: The Nervous System. Protection of the Central Nervous System Scalp and skin Skull and vertebral column Meninges Cerebrospinal fluid (CSF) Blood-brain](https://reader035.vdocuments.mx/reader035/viewer/2022062408/56649efb5503460f94c0e0a7/html5/thumbnails/30.jpg)
PNS: Distribution of Cranial Nerves
Figure 7.24