Brain and Spinal Cord Anatomy: Chapter 12 Study Notes

Posted on Aug 10, 2026 in Biology

1. Major Regions of the Adult Brain

  • Cerebrum: Conscious thought, memory, sensation, voluntary movement
  • Diencephalon: Thalamus, hypothalamus, epithalamus
  • Brainstem:
    • Midbrain
    • Pons
    • Medulla oblongata
  • Cerebellum: Balance, posture, coordination

Memory Trick: CDBC (Cerebrum → Diencephalon → Brainstem → Cerebellum)

2. Ventricles

There are 4 ventricles:

  • Right lateral ventricle
  • Left lateral ventricle
  • Third ventricle
  • Fourth ventricle

CSF Pathway

Lateral ventricles → Interventricular foramina → Third ventricle → Cerebral aqueduct → Fourth ventricle → Median & lateral apertures → Subarachnoid space → Arachnoid villi → Dural venous sinuses

3. Lobes of the Cerebrum

Frontal Lobe

  • Personality
  • Motor cortex
  • Speech (Broca’s area)
  • Planning

Parietal Lobe

  • Somatosensory cortex
  • Touch, pressure, pain, temperature

Temporal Lobe

  • Hearing, smell, memory, language comprehension (Wernicke’s area)

Occipital Lobe

  • Vision

Insula

  • Taste, visceral sensations

Major Fissures

  • Longitudinal fissure: Separates left and right hemispheres
  • Central sulcus: Separates frontal and parietal lobes
  • Lateral sulcus: Separates temporal from frontal/parietal lobes
  • Parieto-occipital sulcus: Separates parietal and occipital lobes

Functional Areas

  • Motor cortex: Movement
  • Premotor cortex: Learned movement
  • Broca’s area: Speech production
  • Primary sensory cortex: Touch
  • Visual cortex: Vision
  • Auditory cortex: Hearing
  • Olfactory cortex: Smell
  • Gustatory cortex: Taste
  • Vestibular cortex: Balance

4. Lateralization

Left Hemisphere

  • Language, logic, math, speech, analytical thinking

Right Hemisphere

  • Creativity, music, facial recognition, spatial awareness, emotions

5. White Matter Fibers

  • Association fibers: Connect within the same hemisphere
  • Commissural fibers: Connect between hemispheres (e.g., corpus callosum)
  • Projection fibers: Connect brain to spinal cord

6. Basal Nuclei (Basal Ganglia)

  • Functions: Start movement, stop unwanted movement, muscle tone, automatic movements
  • Associated Disease: Parkinson’s

7. Diencephalon

Thalamus

Relay station; almost all sensory information passes through here.

Hypothalamus

Controls: ANS, temperature, hunger, thirst, hormones, pituitary gland, sleep.

Epithalamus

Contains the pineal gland; produces melatonin.

8. Brainstem

  • Midbrain: Visual/auditory reflexes, eye movement
  • Pons: Bridge between cerebrum and cerebellum; breathing regulation
  • Medulla: Cardiac center, respiratory center, blood pressure, swallowing, vomiting, coughing

9. Cerebellum

  • Functions: Balance, coordination, smooth movement, posture, muscle memory
  • Damage: Ataxia, tremors, poor balance

10. Limbic System & Reticular Formation

  • Limbic System: Emotion, motivation, memory (includes hippocampus and amygdala)
  • Reticular Formation: Consciousness, alertness, sleep-wake cycle

11. Protection of the CNS

Meninges

  • Dura mater: Tough outer layer
  • Arachnoid mater: Web-like middle layer
  • Pia mater: Thin inner layer attached to the brain

Cerebrospinal Fluid (CSF)

Functions: Cushion, float the brain, nutrient transport, waste removal.

Blood-Brain Barrier

Protects from toxins, pathogens, and harmful chemicals. Formed by capillary endothelial cells and astrocytes.

12. CSF Formation

  • Produced by: Choroid plexus
  • Absorbed by: Arachnoid villi

13. Disorders

  • Stroke (CVA): Blocked artery or bleeding; causes paralysis, speech loss, vision changes.
  • Alzheimer’s: Memory loss, dementia, confusion, amyloid plaques, neurofibrillary tangles.
  • Parkinson’s: Loss of dopamine neurons; causes tremor, rigidity, slow movement.
  • Huntington’s: Inherited; causes chorea, personality changes, dementia.

14. Brain Diagnostic Tests

  • CT: Bleeding, fractures
  • MRI: Best for soft tissue
  • PET: Brain metabolism
  • EEG: Brain electrical activity
  • Angiography: Blood vessels

15. Spinal Cord

  • Functions: Conduct impulses, reflex center
  • Gray matter: Butterfly shape, contains cell bodies
  • White matter: Outside, contains ascending/descending tracts
  • Roots: Dorsal (sensory), Ventral (motor), Dorsal root ganglion (sensory cell bodies)

16. Compare & Contrast

Gray vs. White Matter

  • Gray: Cell bodies, processing
  • White: Axons, communication

Sensory vs. Motor

  • Sensory: Toward CNS
  • Motor: Away from CNS

Thalamus vs. Hypothalamus

  • Thalamus: Sensory relay
  • Hypothalamus: Homeostasis

Cerebrum vs. Cerebellum

  • Cerebrum: Thinking, memory, voluntary movement
  • Cerebellum: Coordination, balance

Flaccid vs. Spastic Paralysis

  • Flaccid: Limp muscles, no reflexes (lower motor neuron damage)
  • Spastic: Stiff muscles, hyperactive reflexes (upper motor neuron damage)

Paralysis vs. Paresthesia

  • Paralysis: Loss of movement
  • Paresthesia: Tingling, numbness, “pins and needles”

Histology to Know

  • Neuron: Cell body (soma), dendrites, axon
  • Neuroglia: Astrocytes, oligodendrocytes, microglia, ependymal cells

High-Yield Multiple Choice Facts

  • Largest brain region: Cerebrum
  • Balance: Cerebellum
  • Relay station: Thalamus
  • Homeostasis: Hypothalamus
  • Melatonin: Pineal gland
  • CSF production: Choroid plexus
  • CSF reabsorption: Arachnoid villi
  • Speech production: Broca’s area
  • Language comprehension: Wernicke’s area
  • Vision: Occipital lobe
  • Hearing: Temporal lobe
  • Voluntary movement: Frontal lobe
  • Touch: Parietal lobe
  • Corpus callosum: Commissural fibers
  • Butterfly-shaped gray matter: Spinal cord