DR

Central Nervous System (CNS) and Human Brain Anatomy

Central Nervous System (CNS) and Human Brain Anatomy

Nervous System

  • Definition: A system of organs and cells coordinating behavior.
  • Components:
    • Central Nervous System (CNS): Brain and spinal cord.
    • Peripheral Nervous System (PNS): Nerves outside the CNS.

Organization of the Nervous System

  • Central Nervous System (CNS)
    • Brain
    • Spinal Cord
  • Peripheral Nervous System (PNS)
    • Somatic Nervous System: Voluntary skeletal muscles.
    • Autonomic Nervous System: Involuntary muscles (organs).
      • Sympathetic: "Fight or flight".
      • Parasympathetic: "Rest & digest".

Central Nervous System (CNS)

  • Functions:
    • Detects environmental changes/stimuli.
    • Processes information to produce responses.
    • Coordinates muscles to produce a response.
  • Spinal Cord:
    • White matter: Axons.
    • Grey matter: Cell bodies, dendrites, and synapses.
    • Central canal: Contains cerebrospinal fluid (CSF) which cushions the brain, acts as a shock absorber, circulates nutrients, and removes waste.

Peripheral Nervous System (PNS)

  • Outside the brain and spinal cord.
  • Functions in physiological responses.
  • Sympathetic response prepares the body for stress.

Brain Structure

  • Divided into two hemispheres connected by the corpus callosum.
  • Lateralization: Hemispheres have different functions.
  • Localization: Specific brain areas control specific behaviors.

Lobes of the Cerebral Cortex

  • Frontal Lobe: Motor area (movement), memory, thinking, planning, language (Broca's area), personality, and prefrontal cortex regulates amygdala activity.
  • Parietal Lobe: Somatosensory area (sensations), integrates information for complex behaviors; orientation and movement; contains somatosensory cortex (processes sensory input).
  • Occipital Lobe: Visual area (processes color, shape, distance).
  • Temporal Lobe: Auditory/language area (processes auditory information), contains Wernicke's area (language comprehension).
  • Cerebellum: Balance and coordination.

Key Areas

  • Broca's Area: Speech production (frontal lobe). Damage leads to Broca's aphasia (difficulty forming words).
  • Wernicke's Area: Speech comprehension (temporal lobe). Damage leads to Wernicke's aphasia (difficulty understanding language).

Brain Anatomy

  • Gyri (ridges), Sulci (grooves), Fissures (deep grooves)

Subcortical Structures

  • Thalamus: Relay station for sensory information; also involved in sleep, wakefulness, and OCD.
  • Hypothalamus: Maintains internal environment and releases hormones to the pituitary gland.
  • Corpus Callosum: Connects brain hemispheres.
  • Cerebellum: Supports movement, balance, coordination and cognition (attention and language).
  • Limbic System:
    • Amygdala: Regulates emotional responses (fight or flight).
    • Hippocampus: Formation of new memories.
    • Prefrontal cortex: Regulates activity of the amygdala.
  • Brainstem:
    • Medulla Oblongata: Regulates autonomic functions (cardiac function, vasodilation, reflexes).
    • Pons: Regulates breathing and REM sleep.
    • Midbrain: Motor movement.