Brain Structures

• Gray matter resides in the cerebral cortex.
• White matter is located in the spinal cord and brainstem.
• Interventricular foramen connects the ventricles.
• Gyri are ridges, while sulci are grooves.
• The central sulcus separates motor and sensory areas.
• The insular lobe is located internally.
• The cerebral cortex is the "executive suite" of the brain.
• The left hemisphere controls language.
• The corpus callosum connects the right and left hemispheres.
• Commissural fibers connect hemispheres; projection fibers do not.
• Ependymal cells line ventricles and circulate CSF.
• Broca’s area, in the left hemisphere, controls motor speech.
• Wernicke’s area controls language understanding.

Thalamus and Diencephalon

• The thalamus is the sorting/relay station in the brain's center.
• The hypothalamus regulates homeostasis: body temperature, sleep, thirst, and blood pressure; it also connects to the pituitary gland.
• The epithalamus contains the pineal gland.
• The hippocampus handles memory formation and consolidation.
• The amygdala (within the limbic system) controls emotion.

Brain Lobes & Areas

• Motor areas are in the frontal lobe.
• Sensory areas are in the parietal/occipital lobes.
• The auditory cortex handles hearing.
• Somatosensory homunculus diagrams brain areas controlling body parts.
• Lateralization is the division of labor between hemispheres.
• The right hemisphere handles emotion and inhibition.

Brainstem & Cerebellum

• The brainstem includes the midbrain, pons, and medulla oblongata.
• The midbrain contains the substantia nigra (linked to Parkinson’s) and superior/inferior colliculi (visual/auditory reflexes).
• The pons helps control breathing rhythm.
• The medulla oblongata controls heart rate, blood pressure, and breathing; its pyramids are where motor fibers cross over.
• The cerebellum coordinates balance and fine motor control.
• Purkinje fibers are large neurons.
• Arbor vitae is a tree-like white matter pattern.
• Olivary nuclei are involved in motor learning.

CNS Support & Protection

• Meninges consist of the dura mater, arachnoid mater, and pia mater.
• The tentorium cerebelli separates the cerebrum from the cerebellum.
• Denticulate ligaments anchor the spinal cord to the dura mater.
• Meningitis is the inflammation of the meninges.

CSF (Cerebrospinal Fluid)

• The choroid plexus produces CSF.
• CSF circulates nutrients and removes waste.
• CSF contains glucose and can carry alcohol, nicotine, bacteria, and viruses (but not urea).
• The blood-brain barrier regulates substances entering the brain from the bloodstream.

Sleep & Brain Activity

• EEG Waves:
• Alpha waves signify relaxation.
• Beta waves signify an alert, active state.
• Theta waves signify light sleep.
• Delta waves signify deep sleep or brain damage.
• Sleep Phases:
• REM (Rapid Eye Movement) involves dreaming.
• Non-REM includes 4 stages; stage 4 is the deepest sleep.
• One sleep cycle lasts about 90 minutes to reach REM.

Memory

• Short-term vs. Long-term memory involves rehearsal and association.
• The hippocampus is key for memory consolidation
• Broca’s area is for speaking.
• Wernicke’s area is for understanding language.

Nervous System Pathways

• A first-order neuron brings sensory input to the spinal cord.
• A second-order neuron relays the signal to the thalamus.
• A third-order neuron delivers the signal to the cortex for perception.

Autonomic Nervous System (ANS)

• The ANS controls involuntary functions: smooth muscles, cardiac muscles, and glands.
• Divisions:
• Sympathetic ("Fight or Flight"): Uses norepinephrine.
• Parasympathetic ("Rest and Digest"): Uses acetylcholine.
• Dual innervation means most organs receive input from both divisions.
• Sympathetic trunk ganglia are chains of nerves beside the spinal cord.
• Parasympathetic fibers arise from cranial and sacral regions.
• Autonomic ganglia are where pre- and postganglionic neurons synapse.

Disorders

• Alzheimer’s disease involves memory loss due to plaque and tangle buildup; acetylcholine increases while dopamine decreases.
• Dementia is a general term for cognitive decline.
• Parkinson’s disease involves the loss of dopamine from the substantia nigra.
• Hydrocephalus is CSF buildup increasing pressure.
• A lumbar puncture withdraws CSF for testing.