Central Nervous System

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Central Nervous System

• Lecture 1

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Central Nervous System

• Components
• Brain
• Spinal Cord
• Meninges (coverings of the CNS)
• Subarachnoid Space (contains CSF)
• Nuclei (specialized gray matter deep within the
  white matter of the brain / brainstem)

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CNS Facts

• The brain weighs approx.ly 3-3.5 lbs.
• It contains 100 billion neurons
• It has an extremely high metabolic rate
• The brain needs a continuous supply of oxygen and
  nutrients
• It needs a continuous mechanism of waste removal

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CNS Facts (continued)

• CSF contributes to providing continuous nutrient
  / waste removal needs
• The brain uses 20 of the total resting cardiac
  output
• Blood is supplied to the brain via the internal
  carotid and vertebral arteries
• Vessels unite in the Circle of Willis

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Development of the Brain

• Prosencephalon (Fore-brain)
• Mesencephalon (Mid-brain)
• Rhombencephalon (Hind-brain)

4 ½ Week Embryo
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5 Regions of the Brain
Telencephalon Diencephalon

• Prosencephalon
• Mesencephalon
• Rhombencephalon

Mesencephalon
Metencephalon Myelencephalon
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Anatomical Structures of the 5 Brain
Regions
Cerebrum/Cortex (Hemispheres)
Telencephalon
Thalamus Hypothalamus Pituitary gland Pineal Gland
Diencephalon
Mesencephalon
Midbrain
Cerebellum Pons
Metencephalon
Medulla Oblongata
Myelencephalon
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Structure of the Cerebrum

• Largest portion of the brain, constituting 80
  of the brains mass
• Responsible for higher mental functions
  (memory/reasoning)
• Consists of right and left hemispheres and
  sectioned into lobes
• Lobes are connected internally by the CORPUS
  CALLOSUM

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Structure (continued)

• Each hemisphere contains a central cavity called
  the lateral ventricle
• Lined w/ Ependymal Cells
• Filled w/ CSF
• Layers of the Cerebrum
• Outer cortex? surface region of gray matter w/
  convolutions
• Sulci (depressions) Gyri (elevations)
• Deep layer? white matter

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Cerebrum
Anterior
Sulcus
Longitudinal Cerebral Fissure
Gyrus
Posterior
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Lobes of the Cerebrum
Central Sulcus
Parietal Lobe
Frontal Lobe
Lateral Sulcus
Occipital Lobe
Temporal Lobe
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Frontal Lobe
Precentral Gyrus

• Precentral Gyrus
• Anterior to the central sulcus
• Primary motor area
• Primary Functions
• Voluntary motor control
• Responses related to personality
• Higher intellectual processes (i.e.
  concentration, planning, decision making)
• Verbal communication

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Parietal Lobe
Postcentral Gyrus

• Postcentral Gyrus
• Posterior to central sulcus
• Primary sensory area
• Primary Functions
• Understanding speech
• Articulating thoughts and emotions
• Interpreting textures and shapes when handled

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Temporal Lobe
Lateral Sulcus

• Separated from the frontal and parietal lobes by
  the lateral sulcus
• Primary Functions
• Contains auditory centers? receives input from
  the cochlea of ear
• Interprets sensory experiences and stores
  memories of auditory and visual experiences
• Fear and some emotions

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Occipital Lobe

• Primary Functions
• Vision Reading
• Integrates eye movements
• Directs/focuses the eyes
• Visual association? correlating images w/
  previous experiences
• Conscious perception of vision

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Insula
Insula

• Cannot be seen from the surface because it is
  deep to the lateral sulcus
• Primary Functions
• Not well understood
• Visceral Autonomic
• Nociception
• Fine sensory perception

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Basal Nuclei areas of gray matter deep within
the white matter of the cortex

• Nuclei include
• Corpus Striatum
• Caudate nucleus (upper mass)
• Lentiform nucleus (lower mass)
• Putamen (lateral portion)
• Globus Pallidus (medial portion)
• Claustrum (just deep to the insula)
• Subthalamic Nucleus
• Substantia Nigra

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Transverse Section
Corpus Callosum
Caudate Nucleus
Putamen
Claustrum
Globus Pallidus
Thalamus (not part of the basal nuclei)
Subthalamic Nucleus Substantia Nigra
Basal Nuclei
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Functions of the Basal Nuclei

• Unconscious contractions of certain skeletal
  muscles
• Regulates muscle tone for certain intentional
  body movements
• Sends almost all of its information to the
  primary motor area
• Damage to this region? variety of motor movement
  dysfunctions (rigidity)

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END

• CNS Part 1