VIII Neuroanatomy and Neurophysiology

• Targets for the Parasympathetic Nervous System (PNS) and the Sympathetic Nervous System (SNS) are mostly the same, but some are different
• Most visceral organs receive dual innervation from both PNS and SNS
• Antagonistic Interactions:

  • Activity of the heart
  • Activity of the GI system
  • Activity of the respiratory system
• Cooperative Effect Example:

  • Regulation of external genitalia during intercourse:
  • PNS: dilation of blood vessels in the penis for erection
  • SNS: drives the process of ejaculation
• Unique Roles of the Sympathetic Nervous System (SNS):

  • SNS regulates:
  • Adrenal medulla
  • Sweat glands
  • Arrector pili muscles of hair follicles
  • Kidneys
  • Most blood vessels
• Metabolic Effects of SNS:

  • Increases metabolic rate of body cells
  • Raises blood glucose levels
  • Stimulates mobilization of fats
  • Increases mental alertness
  • Increases speed/strength of muscle contraction
• Mechanisms of Memory:

  • Storage and retrieval of information
  • Different kinds of memory:
  • Declarative (fact-based) memory
  • Procedural (skill-based) memory
  • Motor memory
  • Emotional memory
• Brain Wave Patterns and the EEG:

  • EEG records neural activity
  • Brain wave patterns:
  • Alpha waves (8-13 Hz)
  • Beta waves (14-30 Hz)
  • Theta waves (4-7 Hz)
  • Delta waves (4 Hz or less)
• Consciousness:

  • Encompasses perception of sensations, voluntary movement control, and higher mental processing
  • 4 levels: alertness, drowsiness, stupor, coma
• Sleep and Sleep-Awake Cycles:

  • REM (rapid eye movement) and NREM (non-rapid eye movement) sleep
  • Alternating cycles follow a 24-hr circadian rhythm
  • Hypothalamic suprachiasmatic nucleus regulates biological clock
  • Sleep helps consolidate new memories and discard old ones
• Sleep Disorders:

  • Narcolepsy: sudden lapsing into sleep at any time of day
  • Insomnia: chronic inability to obtain sufficient sleep
  • Sleep apnea: temporary cessation of breathing during sleep