Lecture Notes: Central Nervous System and Brain Structure

Introduction to the Central Nervous System

• Components: Brain and spinal cord
• Complexity: Human brain is the most complex known object
• Scope of Lecture: Introduction, with more detail in upcoming courses

Early Brain Development

• Neural Tube: Brain and spinal cord begin as a single structure
• Primary Brain Vesicles:
  • Prosencephalon (Forebrain)
  • Mesencephalon (Midbrain)
  • Rhombencephalon (Hindbrain)
• Secondary Brain Vesicles:
  • Forebrain: Becomes telencephalon and diencephalon
  • Midbrain: Remains unchanged
  • Hindbrain: Becomes metencephalon and myelencephalon

Adult Brain Structure

• Regions:
  • Telencephalon: Develops into cerebral hemispheres (cerebrum)
  • Brain Stem: Formed by midbrain and hindbrain segments
• Gyrification: Brain folds to occupy skull volume
• Four Main Regions:
  • Cerebral Hemispheres
  • Diencephalon
  • Brain Stem
  • Cerebellum
• Ventricles: Hollow cavities filled with cerebrospinal fluid

Neuroglia in the Central Nervous System

• Ependymal Cells: Line ventricles
• Astrocytes: Perform regulatory functions
• Microglial Cells: Monitor neuron health
• Oligodendrocytes: Form myelin sheaths

Cerebral Hemispheres

• Structure:
  • Gyri and Sulci: Ridges and grooves
  • Fissures: Deeper grooves, e.g., longitudinal fissure
• Lobes:
  • Frontal, Parietal, Temporal, Occipital, Insula
• Regions:
  • Cerebral Cortex (Gray matter): Contains nerve cell bodies
  • White Matter: Myelinated fibers
  • Basal Nuclei: Gray matter within white matter

Cerebral Cortex

• Function: Seat of the conscious mind
• Composition: Gray matter with six layers of interneurons
• Domains: Responsible for motor and sensory functions
• Functionality:
  • Motor Areas
  • Sensory Areas
  • Association Areas

Motor Areas

• Primary Cortex: Controls voluntary motion
• Premotor Cortex: Plans and sequences movements
• Broca’s Area: Speech production
• Frontal Eye Field: Voluntary eye movement

Sensory Areas

• Primary Somatosensory Cortex: Receives sensory information
• Visual and Auditory Areas: Process visual and auditory information
• Olfactory and Gustatory Cortex: Processes odors and taste
• Visceral Sensory Area: Perception of visceral sensations
• Vestibular Cortex: Perception of balance
• Association Areas: Integrate information across multiple areas

Diencephalon

• Components:
  • Thalamus: Directs information to the cerebral cortex
  • Hypothalamus: Controls autonomic functions
  • Epithalamus: Regulates sleep

Brain Stem

• Components: Midbrain, Pons, Medulla Oblongata

Cerebellum

• Function: Regulates muscle contraction and coordinates motion

Brain Protection

• Meninges: Connective tissue membranes
  • Dura Mater: Outermost layer
  • Arachnoid Mater: Contains blood vessels
  • Pia Mater: Delicate inner layer

Spinal Cord

• Location: Within vertebral column
• Protection: Cerebrospinal fluid and meninges
• Structure: Gray matter (butterfly shape) and white matter
• Functions:
  • Connects with skeletal muscles
  • Contains sensory and motor zones

Summary

• Overview of the central nervous system and brain structure
• Introduction to the spinal cord
• Future lectures will explore the nervous system further