central nervous system cns: brain and spinal cord necessary for the maintenance of homeostasis...
DESCRIPTION
Glial CellsTRANSCRIPT
![Page 1: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/1.jpg)
Central Nervous System
• CNS: brain and spinal cord
• Necessary for the maintenance of homeostasis
• Contains 1011 neurons
• Contains 1014 synapses
• Responsible for everything we perceive, do, feel, and think
![Page 2: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/2.jpg)
Glial Cells
• 90% of CNS composed of glia
• Five types of glial cells
• Astrocyte—numerous functions
• Ependymal cells—line cavities
• Microglia—phagocytes
• Oligodendrocytes—form myelin
• Schwann cells (located in PNS)—form myelin
![Page 3: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/3.jpg)
Glial Cells
![Page 4: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/4.jpg)
Astrocytes
• Remove neurotransmitter from synaptic cleft
• Maintain normal electrolyte composition of spinal fluid in CNS
• Protect neurons against toxic substances
![Page 5: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/5.jpg)
Microglia
• Protect CNS from foreign matter through phagocytosis
• Bacteria
• Dead or injured cells
![Page 6: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/6.jpg)
CNS: Physical Support
![Page 7: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/7.jpg)
Cerebrospinal Fluid (CSF)
• Extracellular fluid of the CNS
• Secreted by ependymal cells
• Functions
• Cushions brain
• Maintains stable fluid environment
![Page 8: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/8.jpg)
Blood Supply to the CNS
• CNS comprises 2% of body weight (3–4 pounds)
• Receives 15% of blood supply
• High metabolic rate
• Brain uses 20% of oxygen consumed by body at rest
• Brain uses 50% of glucose consumed by body at rest
![Page 9: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/9.jpg)
Stroke
• Caused by decreased blood supply
• Occlusion (blockage, closing) of cerebral blood vessel
• Hemorrhage from cerebral blood vessel
![Page 10: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/10.jpg)
Blood-Brain Barrier
• Capillaries
• Sites of exchange between blood and interstitial (space between structures) fluid
![Page 11: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/11.jpg)
CNS: Gray and White Matter
![Page 12: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/12.jpg)
CNS: Gray and White Matter
Figure 9.5b–c
![Page 13: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/13.jpg)
II. Spinal Cord
• Cylinder of nerve tissue
• Continuous with brain
• Surrounded by vertebral column
• Origin of spinal nerves (31 pairs)
![Page 14: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/14.jpg)
Spinal Cord
![Page 15: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/15.jpg)
Spinal Cord: Cross Section
![Page 16: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/16.jpg)
Brain
![Page 17: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/17.jpg)
Midbrain
Spinal cordPonsMedulla oblongata
ForebrainCerebrum
Thalamus
HypothalamusPituitary gland
Brainstem
Diencephalon
Cerebellum
Corpus callosum
(c) Midsagittal section
Brain: Midsagittal View
![Page 18: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/18.jpg)
Premotor cortex(coordinatesvoluntarymovements)
Primary somatosensorycortex (somesthetic sensationsand proprioception)
Sensory associationareas (integration ofsensory information)
Primary motor cortex(voluntary movement)
Central sulcus
Prefrontalassociationareas (idea andplan for voluntarymovement, thoughts,personality)
Broca’s area(speech formation)
Limbic associationcortex (emotions,learning, and memory)
Olfactory cortex(smell)
Visual associationareas (higher visionprocessing)
Wernicke’s area(languagecomprehension)
Auditoryassociationareas
Primary auditorycortex (hearing)
Primary visual cortex(vision)
Functional Areas of CerebrumFunctional Areas of Cerebrum
![Page 19: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/19.jpg)
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.
Reflexes
Automatic patterned response to a stimulus
![Page 20: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/20.jpg)
Reflex Arc
![Page 21: Central Nervous System CNS: brain and spinal cord Necessary for the maintenance of homeostasis Contains 10 11 neurons Contains 10 14 synapses Responsible](https://reader035.vdocument.in/reader035/viewer/2022062905/5a4d1ad27f8b9ab059971adb/html5/thumbnails/21.jpg)
Withdrawal and Crossed-Extensor Reflexes