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.