Brain Higher Functions, Cranial Nerves, and Spinal Cord Anatomy

Comprehensive vocabulary review flashcards covering higher brain functions, language dominance, memory classifications, the consciousness continuum, sleep architecture and physiology, the 12 cranial nerves, and spinal cord anatomy, innervation, and injuries.

Higher Brain Functions

Complex mental activities including thinking, reasoning, memory, comprehension, decision-making, and language, which are primarily associated with the cerebral cortex.

Broca's Area and Wernicke's Area

Two critical regions situated in the association cortex of the left cerebral hemisphere that communicate back and forth to generate speech and comprehend language.

Right Cerebral Hemisphere (in Language)

The non-language dominant hemisphere responsible for interpreting nonverbal emotional components of communication, including facial expressions, body language, gestures, and tone of voice.

Declarative Memory

A category of memory devoted to storing facts, such as names, faces, dates, and words; it is subdivided into working memory and long-term memory.

Working Memory

A short-term category of declarative memory that has a limited storage capacity, such as looking up a telephone number, dialing it, and immediately forgetting it.

Long-Term Memory

A category of declarative memory with an almost limitless storage capacity; its ability to store and retrieve information naturally declines with age.

Procedural Memory

A memory type involving learned motor skills that are acquired and refined through repetition over years, such as tying shoelaces or playing the piano.

Motor Memory

The stored ability to execute coordinated physical movements automatically without conscious thought, such as remembering how to balance and ride a bicycle.

Emotional Memory

The storage and recall of past experiences that are linked to specific emotions, such as the anxiety of an exam, falling in love, or graduation day.

Consciousness

An individual's state of awareness that includes sensory perception, voluntary initiation and control of movements, and higher mental processing capabilities such as logic, judgment, and imagination.

Alertness

The highest state of consciousness along the clinical continuum, in which a person is completely aware of surroundings and in full voluntary control of body movements and speech.

Drowsiness (Lethargy)

A depressed state of consciousness characterized by sluggishness and sleepiness, which directly proceeds to sleep.

Stupor

A severely reduced level of consciousness immediately preceding coma, where the patient does not engage in conversation and only produces a minimal physical or vocal response to painful, vigorous stimuli.

Coma

The most depressed state of consciousness, in which a patient exhibits little to no response to vigorous external stimuli and cortical activity is depressed.

Syncope

A temporary, brief loss of consciousness (fainting), typically caused by inadequate cerebral blood flow resulting from low blood pressure, severe emotional stress, or heart disease.

Sleep

A partial state of unconsciousness controlled by the hypothalamus from which a person can be aroused by stimulation; vital brainstem functions persist while cortical activity is depressed.

REM Sleep (Rapid Eye Movement)

The sleep phase in which most dreaming occurs, during which skeletal muscles are temporarily paralyzed by the inhibitory action of GABA and glycine to prevent acting out dreams.

NREM Sleep (Non-Rapid Eye Movement)

A major division of sleep that alternates with rapid eye movement (REM) sleep in repeating intervals across a $24\text{-hour}$ circadian rhythm.

Antidiuretic Hormone (ADH) in Sleep

A hormone secreted during sleep that reduces urine output so that an individual can sleep through the night; declining nocturnal production with aging leads to frequent nighttime urination.

Cytokines in Sleep

Immune system chemical messengers released during sleep that regulate immune responses, promote recovery, and fight against infection and inflammation.

Cranial Nerves

Twelve pairs ($12$ pairs) of peripheral nerves that arise directly from the inferior base of the brain, designated by Roman numerals I through XII.

Olfactory Nerve (CN I)

Cranial nerve I; a sensory nerve whose sole function is the sense of smell.

Optic Nerve (CN II)

Cranial nerve II; a sensory nerve dedicated to vision.

Oculomotor Nerve (CN III)

Cranial nerve III; functions to adjust pupil diameter, focus the lens, raise the eyelids, and rotate the eyeballs.

Trochlear Nerve (CN IV)

Cranial nerve IV; functions in motor control to move the eyeballs.

Trigeminal Nerve (CN V)

Cranial nerve V; provides motor innervation for chewing (mastication) and sensory innervation for sensations of the face and mouth.

Abducens Nerve (CN VI)

Cranial nerve VI; provides motor innervation to move the eyeballs laterally.

Facial Nerve (CN VII)

Cranial nerve VII; responsible for facial expressions, tear production, and sensory sensations from the tongue.

Branches of the Facial Nerve

The five peripheral motor branches of Cranial Nerve VII: Temporal, Zygomatic, Buccal, Mandibular, and Cervical.

Vestibulocochlear Nerve (CN VIII)

Cranial nerve VIII; a sensory nerve that mediates hearing and balance (equilibrium).

Glossopharyngeal Nerve (CN IX)

Cranial nerve IX; responsible for producing saliva, swallowing, and taste sensations.

Vagus Nerve (CN X)

Cranial nerve X; provides extensive parasympathetic autonomic regulation over peripheral organs and mediates the gag reflex.

Accessory Nerve (CN XI)

Cranial nerve XI; controls skeletal movements of the neck and shoulder and assists in swallowing.

Hypoglossal Nerve (CN XII)

Cranial nerve XII; innervates muscles of the tongue to form speech, move the tongue, and swallow.

Spinal Cord Anatomy

The central nerve cord extending from the foramen magnum (continuous with the medulla oblongata) down to the first lumbar vertebra ($L1$), composed of $31$ segments that each give rise to a pair of spinal nerves.

Spinal Cord Cross Section

An oval-shaped cross section featuring inner gray matter (dorsal and ventral horns, gray commissure, and central canal) surrounded by white matter tracts, connected to dorsal and ventral nerve roots.

Cauda Equina

A bundle of nerve roots located within the vertebral canal inferior to the termination of the spinal cord in the lumbar region, named for its resemblance to a horse's tail.

High Cervical Injury ($C1$-$C2$)

A severe spinal cord transection occurring between $C1$ and $C2$ that carries a mortality rate of nearly $100\%$ due to loss of respiratory and vital autonomic control.

Tetraplegia (Quadriplegia)

Paralysis affecting the trunk and all four limbs caused by cervical spine injury, resulting in complete paralysis below the neck at $C4$ or partial paralysis of the hands, arms, and lower body at $C6$.

Paraplegia

Paralysis affecting the lower half of the body resulting from thoracic or lumbar cord lesions, producing paralysis below the chest at $T4$ or paralysis below the waist at $L1$.

Upper Limb Nerves

Major peripheral nerves supplying the shoulder and upper extremity: the axillary nerve, radial nerve, median nerve, and ulnar nerve.

Lower Limb Nerves

Major peripheral nerves supplying the pelvic and lower extremity regions: the pudendal nerve, sciatic nerve, common fibular nerve, and tibial nerve.

Sciatica

Radiating pain that results from irritation, compression, or pinching of the sciatic nerve.

Causes of Sciatica

Pathological conditions that compress the sciatic nerve, most commonly contracture of the piriformis muscle (piriformis syndrome) or herniated/bulging intervertebral discs causing local nerve inflammation.