Brain Anatomy and Function Overview

Central Nervous System Components

• Central Cells: Located in the brain and extending from the brain stem.
• Cranial Nerves:
  • 12 nerves.
  • Important to know their names, functions, and autonomic roles.

Brain Structure

• Cerebrum:
  • Comprised of two hemispheres, each containing lobes aligned with skull bones.
• Cerebellum:
  • Involved in motor control and coordination.
• Brain Stem:
  • Medulla Oblongata
  • Pons
  • Midbrain
• Diencephalon:
  • Three parts:
    • Thalamus
    • Hypothalamus: Most functions occur here.

Brain Surface Texture

• Sulci (Valles): Grooves on the brain surface.
• Gyri (Hills): Raised portions on the brain surface.

Gray and White Matter

• Gray Matter:
  • Composed of neuron cell bodies, dendrites, and unmyelinated axons.
  • Located on the brain's surface and responsible for decision-making.
• White Matter:
  • Made of myelinated axons.
  • Located deeper in the brain, responsible for information transmission.

Brain Pathways

• Ganglion: Collection of neuron cell bodies.
• Center/Nucleus: Processing centers in the brain.

Protection and Support

• Skull: Physical protection.
• Cerebrospinal Fluid (CSF): Brain floats in this fluid.
• Meninges: Layers of connective tissue surrounding the brain and spinal cord.
  • Arachnoid: Spiderweb-like layer.
  • Dura Mater: Non-stretchable, two layers (meningeal and periosteal).
  • Subdural Space: Normally not containing fluid.
  • Pia Mater: Carries blood vessels into the brain.

Dura Mater Extensions

• Falx Cerebri: Separates right and left cerebral hemispheres.
• Tentorium Cerebelli: Covers the cerebellum and cerebrum.
• Diaphragma Sellae: Covers the pituitary gland.

Dural Sinuses

• Act as blood vessels, but are not actual blood vessels:
  • Superior Sagittal Sinus
  • Inferior Sagittal Sinus

Brain Ventricles

• Fluid-filled spaces where CSF is produced.
• Lateral Ventricles: Two, one in each hemisphere.
• Third Ventricle: Largest, situated along the midline.

Cerebrospinal Fluid (CSF)

• Provides protection and buoyancy.
• Clear, colorless fluid.
• Ensures environmental stability, carries oxygen and nutrients, and removes waste.
• Choroid Plexus: Site of CSF production, involves capillaries and ependymal cells.
• Arachnoid Villi: Structures protruding into the brain.

Blood-Brain Barrier

• Formed by astrocytes with perivascular feet.
• Limits substances entering the brain; only small, non-polar, lipid-soluble substances.
• Allows entry for some substances like alcohol, nicotine, and certain viruses.

Cerebrum Details

• Cerebral Cortex: Involved in higher brain functions.
• Longitudinal Sulcus: Separates right and left hemispheres.
• Central Sulcus: Separates frontal and parietal lobes.

Lobes of the Cerebrum

• Frontal Lobe:

  • Controls voluntary motor activities.
  • Personality, verbal communication, and decision-making.
  • Precentral Gyrus: Primary motor cortex.
  • Broca's Area: Controls speech-related muscles (left frontal lobe).
  • Frontal Eye Field: Involved in eye movement and focus.
  • Pre-Motor Cortex: Voluntary skeletal muscle control.
  • Prefrontal Cortex: Risk-benefit analysis and planning.

• Other Lobes: Named for the skull bones they cover. Include temporal, parietal, occipital, and the insular lobe (not visible externally).

Additional Brain Features

• Wernicke's Area: Involved in language comprehension.
• Basal Ganglia: Involved in motor control.
• Thalamus: Relay for all sensory information except vision.

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These notes capture the key elements of brain anatomy and function as discussed in the lecture, focusing on structural and functional aspects essential for understanding the central nervous system.