Lecture Notes: Central Nervous System (CNS) - Parts 3 and 4

Introduction

• Lecture recording has begun
• Focuses on parts 3 and 4 of the CNS
• Reminder on muting microphones to avoid background noise

Overview of the Central Nervous System

• Composed of the brain and spinal cord
• Brain divided into left and right cerebral hemispheres
  • Contralateral control: right hemisphere controls left body and vice versa
• Cerebrum: site of the conscious mind (cortex)
  • Cortex: outer gray matter (~40% of brain mass)

Brain Systems and Functions

• Limbic System

  • Associated with emotion
  • Involves amygdaloid body (recognizes fear, anger) and cingulate gyrus (gestures, conflict resolution)
  • Interacts with prefrontal cortex (judgment, personality)
  • Puts emotion to odors

• Reticular Formation and Activation System (RAS)

  • Keeps brain alert and awake
  • Inhibited during sleep
  • Filters out weak stimuli

Brain Structures Related to Consciousness and Sleep

• Association Areas

  • Anterior (prefrontal cortex), posterior, and limbic
  • Role in judgment, personality, emotions

• Memory and Learning

  • Types: declarative, procedural, motor, and emotional memory
  • Short-term vs. long-term memory
  • Factors aiding memory transfer: emotional state, rehearsal, association

• Sleep

  • Two types: NREM (non-rapid eye movement) and REM (rapid eye movement)
  • REM sleep: restorative, dreams occur
  • Sleep cycles: cycle through NREM stages 1-4 and REM

Brain Waves and Consciousness

• EEG records brain's electrical activity
• Types of waves:
  • Alpha: idling brain (awake, relaxed)
  • Beta: alert brain
  • Delta: deep sleep
  • Theta: common in children

Disorders and Conditions

• Epilepsy

  • Seizures, can lose consciousness
  • Types: absence (petite mal) and tonic-clonic (grand mal)

• Sleep Disorders

  • Narcolepsy: uncontrollable sleep attacks
  • Insomnia: trouble sleeping

• Brain Injuries

  • Concussion: temporary function alteration
  • Contusion: permanent damage

CNS Protection

• Meninges

  • Three layers: dura mater (tough), arachnoid mater (spider web-like), pia mater (delicate)
  • Meningitis: inflammation of meninges

• Blood-Brain Barrier

  • Protects brain from harmful substances
  • Selective permeability (allows glucose, restricts most drugs)

CNS Disorders

• Stroke

  • Caused by blood flow interruption
  • Can lead to paralysis

• Neurodegenerative Diseases

  • Alzheimer's: memory loss, associated with beta-amyloid plaques
  • Parkinson's: affects movement, basal nuclei degeneration
  • Huntington's: genetic, motor dysfunction

Spinal Cord and Reflexes

• Spinal cord: part of CNS, contains gray and white matter
• Gray Matter in Spinal Cord
  • Dorsal horns: sensory
  • Ventral horns: motor
• Spinal Nerves
  • Emerge from spinal cord, part of peripheral nervous system

Spinal Cord Pathways

• Ascending Pathways

  • Sensory information to the brain

• Descending Pathways

  • Motor commands from the brain to effectors

Conclusion

• Importance of understanding CNS functions for overall neurological health

Note:

These notes are a summarized version of the key points covered in the lecture and serve as a study guide for understanding the central nervous system's complex structure and functions.