Central Nervous System: The Brain and Spinal Cord

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Central Nervous SystemThe Brain and Spinal Cord

• The Nervous System
• Option E

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The Brain

• Most developed/complex organ of the body.
• Cephalization

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4 Major Regions

1. Cerebral Hemispheres
2. Diencephalon
3. Thalamus
4. Hypothalamus
5. Epithalamus
6. Brain Stem
7. Midbrain
8. Pons
9. Medulla
10. Cerebellum

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Cerebrum
Diencephalon
Brain stem
Cerebellum
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Gray Matter vs. White Matter

• Unmyelinated fibers
• Concentrated area of neuron cell bodies
• Found
• Outer Cortex
• Surrounding Central
• Canal
• Scattered w/White Matter

• Myelinated fibers
• Found
• Between gray matter layers

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Ventricles

• Hollow chambers within the brain
• Flow into Central Canal
• Filled with Cerebrospinal Fluid (CSF)
• Divided into Segments
• Lateral Ventricles ? in cerebral hemispheres
• Third Ventricle ? in diencephalon
• Fourth Ventricle ? in pons / medulla

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Lateral ventricles
Third ventricle
Fourth ventricle
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1. CEREBRAL HEMISPHERES

• Most superior, largest part (83)
• elevated ridges? gyri (gyrus)
• shallow grooves ?sulci (sulcus)
• deep grooves ?fissures
• longitudinal fissurebtwn. hemispheres
• transverse fissure btwn. cerebrum
• and cerebellum

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Are the Hemispheres Connected?

• CORPUS
• CALLOSUM

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Cerebrum Divided into5 Major LOBES

• Frontal Lobe
• Parietal Lobe
• Temporal Lobe
• Occipital Lobe
• Insula

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Parietal lobe
Central sulcus
Occipital lobe
Precentral gyrus
Postcentral gyrus
Frontal lobe
Temporal lobe
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• INSULA

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Cerebral Hemispheres divided into3 REGIONS

1. Cerebral Cortex
2. Cerebral White Matter
3. Cerebral Basal Nuclei

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The Cerebral Cortex

• Area of consciousness
• Composed of gray matter
• All interneurons !
• No functional area acts alone!

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3 areas of Cerebral Cortex

• Motor Area
• Sensory Area
• Association Area
• Dont confuse w/ Motor, Sensory Neurons!
• Areas detected by modern imaging techniques

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Motor Area of Cerebral Cortex

• Located in precentral gyrus
• Controls all voluntary movements
• Subdivided into
• Premotor cortex
• Primary motor cortex
• Brocas region

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• Premotor cortex
• Located anterior to precentral gyrus
• Controls LEARNED, repetitive skills!
• Musical instrument playing
• Keyboarding, writing

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• Brocas Region
• Located anteriorly/inferiorly to premotor cortex
• Left hemisphere only
• Controls MOTOR SPEECH
• Talking!

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• Primary Motor Cortex
• Controls voluntary movement of skeletal muscles!
• Precise motor control regions dominant here!

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Homunculus
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Sensory Area of Cerebral Cortex

• Located in postcentral gyrus
• Controls all sensation capabilities
• Subdivided into
• Somatosensory cortex
• Association cortex
• Visual cortex
• Auditory cortex
• Olfactory cortex
• Gustatory cortex
• Vestibular cortex

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• SOMATOSENSORY
• CORTEX

• Controls tactile sensations in skin and skeletal
  muscles
• What part of the body is most sensitive to touch?

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• ASSOCIATION CORTEX

• Receives information from somatosensory cortex
• Allows for understanding of tactile sensations!

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• VISUAL
• CORTEX

• Receives information from eyes
• Segments allow for
• identification of images
• location/position of images

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• AUDITORY
• CORTEX

• Receives information from ears
• Allows for identification of sounds

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• OLFACTORY
• CORTEX

• Receives information from smell receptors
• Allows for identification of SCENTS

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• GUSTATORY
• CORTEX

• Receives information from the tongue
• Allows for identification of TASTES

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• VESTIBULAR
• CORTEX

• Receives information from inner ear
• Allows for maintenance of BALANCE

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• Prefrontal
• Cortex

• Controls intellect, learning, personality,
  abstract thinking, judgement, reasoning,
  planning, compassion, conscience, moral thought,
  etc.
• Develops slowly
• Linked to Limbic System

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• WERNICKES
• REGION

• Understanding spoken/written language
• Reminder
• What region allows for ability to speak?

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• VISCERAL
• AREA

• Perception of internal body sensations
• full bladder
• nausea, etc.