Central Nervous System: Brain Anatomy, Sleep, and Clinical Pathology

Vocabulary flashcards covering brain regions, sleep regulation, meninges, cerebrospinal fluid, vascular emergencies, and neurological homeostatic imbalances.

Cerebellum

A brain structure accounting for $11\%$ of brain mass that coordinates precise skeletal muscle movements based on inputs from the cortex, brain stem, and sensory receptors, while also playing a major role in balance.

Arbor vitae

The distinctive treelike pattern of white matter contained within the thin outer cortex of gray matter in the cerebellum.

Limbic system

A functional brain network that comprises a large part of the emotional brain and links emotional responses to odors.

Reticular activating system (RAS)

A system that sends continuous impulses to the cerebral cortex to maintain consciousness and alertness, filtering out roughly $99\%$ of familiar, repetitive, or weak stimuli.

Anterograde amnesia

A condition resulting from bilateral hippocampal damage where previously consolidated memories remain intact, but new sensory inputs cannot be committed to long-term memory.

Retrograde amnesia

A memory disorder characterized by the loss of memories formed in the distant past.

Electroencephalogram (EEG)

A diagnostic recording of the electrical activity accompanying brain function, measured via electrodes placed on the scalp to detect potential differences between cortical areas.

Epileptic seizure

A condition involving a sudden torrent of electrical discharges by groups of neurons that blocks other signals from passing through, often leading to loss of consciousness and uncontrolled jerking.

Aura

A sensory hallucination that may immediately precede the onset of an epileptic seizure.

Syncope

A brief loss of consciousness, commonly referred to as fainting, typically caused by inadequate cerebral blood flow from low blood pressure, hemorrhage, or sudden emotional distress.

Coma

A state of prolonged unconsciousness characterized by significantly depressed oxygen consumption compared to normal sleep.

Brain death

A state of irreversible coma used as a clinical and legal determinant of whether a person is alive or deceased.

Sleep

A state of partial unconsciousness from which an individual can be aroused by external stimulation, categorized by EEG patterns into NREM and REM stages.

Narcolepsy

A neurological sleep disorder marked by abrupt lapses into sleep directly from an awake state, associated with immune destruction of hypothalamic orexin-producing cells.

Orexins

Hypothalamic peptides that serve as chemical wake-up signals regulating the sleep-wake cycle.

Insomnia

A chronic inability to obtain the necessary quantity or quality of sleep, which can potentially be treated by blocking orexin receptors.

Dura mater

The toughest, outermost layer of the cranial meninges that surrounds and protects the central nervous system.

Arachnoid mater

The web-like middle meninx separated from the dura mater by the subdural space, containing a subarachnoid space filled with CSF and major blood vessels.

Pia mater

The delicate, vascularized inner meninx that adheres directly to the brain surface, following every gyral convolution.

Meningitis

An inflammation of the meningeal membranes surrounding the brain and spinal cord, typically diagnosed via lumbar puncture to culture CSF microbes.

Cerebrospinal fluid (CSF)

A clear liquid cushion surrounding the brain and spinal cord that reduces the brain's effective weight by $97\%$ through buoyancy, while nourishing tissue and transporting chemical signals.

Blood-brain barrier

A selective physiological barrier that maintains a stable neuronal environment by permitting facilitated diffusion of key nutrients and passage of fat-soluble compounds while blocking wastes, toxins, and $K^+$ ions.

Concussion

A mild traumatic brain injury marked by a temporary alteration in normal cerebral function.

Contusion

A traumatic brain injury resulting in permanent structural bruising and tissue damage.

Cerebral edema

Pathological swelling of brain tissue that frequently follows traumatic head injury.

Cerebrovascular accident (CVA)

A condition commonly known as a stroke, occurring when localized blood flow to brain tissue is obstructed by a clot, leading to infarction and possible hemiplegia.

Ischemia

The reduction or complete deprivation of blood supply to a tissue, which deprives cells of oxygen and causes neuronal death in brain tissue.

Transient ischemic attack (TIA)

A temporary, self-resolving episode of cerebral ischemia that produces transient neurological deficits without permanent damage.

Tissue plasminogen activator (TPA)

An intravenous thrombolytic drug that is currently the only approved pharmacological treatment for acute ischemic stroke.

Alzheimer's disease (AD)

A progressive degenerative brain disorder linked to misfolded protein accumulation and neurodegeneration, causing memory loss, language deficits, disorientation, and cortical atrophy.

Parkinson's disease

A progressive motor disorder caused by the degeneration of dopamine-releasing neurons in the brain, currently targeted by stem cell transplantation research.