Central Nervous System Lecture Notes

General Information

• Central Nervous System (CNS): Consists of the brain and spinal cord.
  • Brain composed of left and right cerebral hemispheres.
  • Contralateral control: Right hemisphere controls left body and vice versa.

Brain Structure and Function

• Cerebrum:

  • Site of the conscious mind, involving the cortex (outer gray matter).
  • Cerebral cortex accounts for about 40% of the brain's mass.
  • Associated with awareness and voluntary actions.

• Limbic System:

  • Associated with emotions ("emotion, emotion, emotion").
  • Influences memory, emotion, and behavior.
  • Key structures: Amygdala (fear, anger), cingulate gyrus (emotion gestures), hypothalamus (emotional responses).

• Association Areas:

  • Anterior (prefrontal cortex): Judgment, personality.
  • Posterior and Limbic.

Reticular Formation and Activation System

• Reticular Activation System (RAS):
  • Responsible for alertness and awareness.
  • Inhibited during sleep.
  • Filters out repetitive/unimportant stimuli.

Memory and Learning

• Memory Types:

  • Declarative: Facts and data.
  • Procedural: Skills.
  • Motor: Skills like riding a bike.
  • Emotional: Tied to emotions.

• Memory Processes:

  • Short-term vs. Long-term memory.
  • Emotional state and repetition aid in consolidating memory.

Sleep and Consciousness

• Sleep Stages:

  • NREM: 4 stages, transitioning to REM.
  • REM: Dreaming, restorative sleep.

• Consciousness:

  • Cerebral cortex involvement.
  • Voluntary actions, memory, logic.

Brain Waves

• Types of Brain Waves:
  • Alpha: Relaxed, idling.
  • Beta: Mentally alert.
  • Theta: Common in children.
  • Delta: Deep sleep.

Disorders and Conditions

• Epilepsy:

  • Seizures result in loss of consciousness.
  • Types: Tonic-clonic (grand-mal), Absence (petit-mal).
  • Treatments: Anticonvulsants enhancing GABA.

• Memory Loss:

  • Amnesia: Anterograde (new memories lost), Retrograde (past memories lost).

• Brain Injuries:

  • Concussion vs. Contusion.
  • Stroke: Caused by blood flow disruption.

• Neurodegenerative Diseases:

  • Alzheimer's: Memory loss, dementia.
  • Parkinson's: Motor control loss.
  • Huntington's: Uncontrolled movement.

Spinal Cord

• Structure:

  • Gray matter (inner): Dorsal (sensory), Ventral (motor) horns.
  • White matter (outer): Myelinated fibers.

• Functions:

  • Ascending Pathways: Sensory information to brain.
  • Descending Pathways: Motor commands from brain.

• Spinal Cord Injuries:

  • Quadriplegia: Cervical damage.
  • Paraplegia: Thoracic or lumbar damage.

Protective Structures

• Meninges:

  • Dura mater (tough), Arachnoid mater (web-like), Pia mater (delicate).
  • Inflammation: Meningitis.

• Cerebrospinal Fluid (CSF):

  • Cushions the brain, provides nutrients.
  • Blockage: Hydrocephalus.

• Blood-Brain Barrier:

  • Protective barrier, selective permeability.

Additional Notes

• Diagnostic Tools:

  • EEG: Brain electrical activity.
  • MRI, CT scans for imaging.

• Developmental Disorders:

  • Cerebral Palsy: Usually due to lack of oxygen.
  • Spina Bifida: Spinal cord development issues.

• Ensure to know anatomical terms, functions, and differences between conditions for examinations.