Neuroanatomy

Orientation in Neuroanatomy

  • Dorsal (superior): up

  • Caudal (posterior): back

  • Ventral (inferior): down

  • Rostral (anterior): front

  • Orientation is at a 90-degree angle to the brain

  • Medial: middle

  • Lateral: to the side

Brain Sections

  • Types of Sections:

    • Axial: top and bottom

    • Sagittal: right and left

    • Coronal: front and back

  • Nervous System:

    • Central nervous system (CNS): brain and spinal cord

    • Peripheral nervous system (PNS):

      • Somatic: senses and responds to the environment

      • Autonomic: regulates internal functions and controls glands/muscles

Protection of the Brain

  • Skull: physical protection

  • Cerebrospinal Fluid (CSF):

    • Salty liquid protecting brain/spinal cord against impact

    • Removes metabolic waste

    • Lack of CSF increases injury risk

  • Ventricles: fluid-filled spaces within the brain

  • Meninges: three protective membranes

    • Dura Mater

    • Arachnoid Mater

    • Pia Mater

Blood-Brain Barrier

  • Structure of cerebral blood vessels: tightly packed to prevent pathogens

  • Drugs need formulation that can bypass this barrier

Brain Hemispheres

  • Two Hemispheres:

    • Left Hemisphere

    • Right Hemisphere

  • Commissures: white matter pathways connecting hemispheres

  • Corpus Callosum: major connection between hemispheres

  • Grey Matter: 40% neuronal cell bodies (neurons)

  • White Matter: 60% axons covered in myelin

Spinal Cord

  • Structure: densely packed nerve fibers transmitting messages

  • Contains both grey and white matter

Cerebral Cortex

  • Gyri: bumps (ridges)

  • Sulci: grooves (creases or fissures)

  • Fissures: deeper grooves between gyri

Cortical Layers

  • Varying types, densities, and sizes of neurons

  • Subcortical Structures: deep brain areas

  • Brodmann Areas: 52 cortical regions defined by morphology, now expanded to >200

Major Brain Subdivisions

  • Three Major Subdivisions:

    • Forebrain: includes thalamus, hippocampus, amygdala

    • Cerebrum

    • Basal Ganglia

    • Midbrain

    • Hindbrain

    • Cerebellum

  • Information processing begins in the posterior brain and becomes complex as it moves anteriorly.