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Learning Objectives

• Study of the brain (CNS) and cranial nerves (PNS).
• Review skull and meninges layers.
• Identify brain structures and functional areas.
• Briefly describe functions of 12 cranial nerves.

Central Nervous System

• Brain and spinal cord housed in the dorsal cavity.
• Skull protects the brain.
• Meninges: Pia mater, Arachnoid mater, Dura mater (contain CSF).

Ventricles and Cerebrospinal Fluid (CSF)

• 4 ventricles: 2 lateral, third, and fourth.
• Each ventricle has choroid plexus, which secretes CSF.
• CSF formed in choroid plexus, flows at 400-600ml daily.

Brain Structure

• Divided into left and right hemispheres (longitudinal fissure).
• Joined by corpus callosum.
• Gyri and sulci define the cerebral cortex (grey matter). White matter consists of axons.

Major Parts of the Brain

• Cerebrum (largest), Lobes: Frontal, Parietal, Temporal, Occipital.
• Functional Areas:
  • Frontal: motor control, higher processes; includes Broca’s area.
  • Parietal: somatosensory processing.
  • Temporal: auditory processing, Wernicke’s area for language.
  • Occipital: visual processing.

Cerebellum

• Located below occipital and temporal lobes.
• Functions: coordination, balance, motor learning.
• Known as the "little brain."

Diencephalon

• Comprises thalamus, hypothalamus, and epithalamus.
• Functions include processing sensory/motor signals, regulating sleep/appetite, and hormonal functions.

Brain Stem

• Vital for cardiac and respiratory functions; regulates heart rate and blood pressure.
• Composed of midbrain, pons, and medulla oblongata.

Cranial Nerves

• 12 pairs; sensory, motor, or mixed functions.
• Important for neurological exams.
• Key functions:
  • Olfactory: smell
  • Optic: vision
  • Oculomotor: eye movement
  • Facial: expressions and taste
  • Vagus: visceral functions
  • Accessory: shoulder movement
  • Hypoglossal: tongue movement.