The Brain

The Central Nervous System (CNS)

  • Comprises the brain and spinal cord

  • Involved in movement, sensory interpretation, homeostasis, and cognitive functions.

The Brain Structure

  • Cerebrum: Responsible for higher mental functions.

    • Gross anatomy features: sulci (grooves), gyri (ridges), fissures (deep grooves).

Cerebral Lobes

  • Frontal Lobes: Anterior region; responsible for planning movement, complex mental functions (behavior, conscience, personality).

  • Parietal Lobes: Posterior to frontal lobes; processes sensory information, attention.

  • Temporal Lobes: Lateral surface; involved in hearing, language, memory, and emotions.

  • Occipital Lobes: Posterior region; processes visual information.

  • Insulas: Deep under lateral fissures; involved in sensorimotor functions, decision making, emotions, and self-awareness.

Cerebral Cortex

  • Composed mainly of gray matter; most complex part of the cortex.

  • Includes neocortex divided into:

    • Primary Motor Cortex: Plans and executes movement.

    • Primary Sensory Cortices: Processes sensory input (S1: touch, temperature; S2: integration).

    • Association Areas: Integrates information from various modalities.

Multimodal Association Areas

  • Broca’s Area: In frontal lobe; crucial for speech production.

  • Wernicke’s Area: In temporal and parietal lobes; essential for understanding language.

  • Prefrontal Cortex: Involved in behavior modulation, personality, learning, and memory.

Basal Ganglia

  • Deep gray matter structures involved in movement (includes caudate nucleus, putamen, globus pallidus).

Cerebral White Matter

  • Types:

    • Commissural Fibers: Connect hemispheres.

    • Association Fibers: Connect areas within the same hemisphere.

    • Projection Fibers: Connect to deep nuclei, brainstem, cerebellum, and spinal cord.

The Limbic System

  • A functional brain system involved in memory, emotion, and behavior; includes the limbic lobe, hippocampus, and amygdala.

Diencephalon

  • Located below the cerebrum; includes:

    • Thalamus: Main entry point to the cerebral cortex.

    • Hypothalamus: Regulates autonomic functions, temperature, hunger, thirst, and links to pituitary gland.

The Cerebellum

  • Coordinates movement by interacting with cerebral cortex, basal nuclei, and brainstem.

The Brainstem

  • Comprises midbrain, pons, and medulla oblongata; controls basic homeostatic functions.

  • Midbrain: Relay system for vision and hearing; involved in motor movement.

  • Pons: Regulates movement and sleep.

  • Medulla Oblongata: Vital for heart rate, breathing, and blood pressure regulation.

Reticular Formation

  • Collection of nuclei in the brainstem; involved in sleep regulation, mood, and motor functions for skeletal and autonomic systems.