NS LM3 key terms

The basic signaling cell of the nervous system, composed of a cell body, dendrites that receive input, and an axon that transmits electrical impulses to other cells.

Supporting cells of the nervous system that do not conduct impulses but nourish, insulate, and protect neurons; examples include astrocytes, oligodendrocytes, microglia, and ependymal cells.

A rapid, all-or-none electrical change across a neuron membrane caused by ion flow, which carries a signal along the axon and triggers neurotransmitter release at the terminal.

The junction where one neuron communicates with another cell, consisting of a presynaptic terminal, a synaptic cleft, and a postsynaptic membrane bearing receptors.

A chemical released from a nerve terminal that crosses the synaptic cleft and binds receptors on the next cell, exciting or inhibiting it; examples include dopamine, serotonin, and acetylcholine.

A fatty sheath wrapped around axons by oligodendrocytes in the brain and Schwann cells in peripheral nerves, which speeds impulse conduction and is lost in demyelinating disease.

A selective filter formed by tight junctions between brain capillary endothelial cells and astrocyte processes, restricting which substances and drugs can pass from blood into brain tissue.

The outer layered gray matter of the cerebral hemispheres, responsible for conscious sensation, voluntary movement, language, and higher cognitive functions, organized into lobes with distinct roles.

The anterior cerebral lobe governing voluntary motor control, expressive language, planning, judgment, and personality; injury may produce weakness, aphasia, or behavioral change.

A structure behind the brainstem that coordinates movement, maintains balance and posture, and refines motor skills; damage causes ataxia, tremor, and unsteady gait.

The midbrain, pons, and medulla collectively, containing cranial nerve nuclei and pathways for consciousness, breathing, and blood pressure; injury here can be life-threatening.

Twelve paired nerves arising from the brain and brainstem that serve sensory, motor, and autonomic functions of the head and neck, assessed individually during neurological examination.

Clear fluid produced in the ventricles that cushions the brain and spinal cord, removes waste, and is sampled by lumbar puncture to diagnose infection, bleeding, or inflammation.

A nerve cell whose body lies in the brain or brainstem and whose axon descends to control lower motor neurons; damage produces spasticity, hyperreflexia, and a positive Babinski sign.

A nerve cell in the spinal cord anterior horn or brainstem that directly innervates skeletal muscle; damage causes flaccid weakness, atrophy, fasciculations, and reduced reflexes.

The degree to which a patient is awake and responsive, ranging from alert to comatose; it is the most sensitive early indicator of deteriorating brain function.

A standardized 3-to-15 score summing eye opening, verbal response, and motor response, used to grade consciousness and detect deterioration after head injury or stroke.

Constriction of the pupil when light strikes the retina, mediated by cranial nerves two and three; its loss or asymmetry can signal brainstem compression or herniation.

An involuntary muscle contraction elicited by tapping a tendon, graded from absent to brisk; comparison of sides helps localize upper versus lower motor neuron lesions.

A zero-to-five scale describing voluntary contraction, from no movement to normal power against resistance, recorded for each limb group to track weakness over time.

Sudden brain injury from blocked blood flow, most often an occluded cerebral artery, causing focal deficits; time-critical treatment aims to restore perfusion before tissue dies.

Bleeding into or around brain tissue, usually from a ruptured vessel or aneurysm, producing headache, vomiting, and rapid decline; anticoagulants worsen it and clot-busting drugs are contraindicated.

A transient episode of abnormal excessive electrical activity in the brain causing altered movement, sensation, awareness, or behavior; safety precautions focus on preventing injury during the event.

A chronic disorder marked by recurrent unprovoked seizures, diagnosed after appropriate evaluation and usually managed with long-term medication and lifestyle counseling.

An immune-mediated disease that damages myelin in the central nervous system, causing relapsing sensory, motor, visual, and bladder symptoms that worsen with heat and fatigue.

An acquired language disorder from damage to language areas, most often the left hemisphere, affecting expression, comprehension, reading, or writing while intellect may remain intact.

Uncoordinated, clumsy movement with poor balance and a wide-based gait, arising from cerebellar or sensory pathway dysfunction rather than from muscle weakness itself.

A rapid X-ray-based imaging study that shows bone and acute bleeding well; it is the first test for suspected stroke or head trauma because it distinguishes hemorrhage from ischemia quickly.

Imaging that uses magnetic fields and radio waves to give detailed soft-tissue views of brain and spinal cord; it requires screening for metal implants and may need sedation for claustrophobic patients.

Insertion of a needle into the lower spinal canal to sample cerebrospinal fluid for analysis or to measure pressure; position and post-procedure flat rest reduce headache risk.

A recording of electrical brain activity through scalp electrodes, used to detect seizure patterns, evaluate altered consciousness, and monitor brain function during certain procedures.

Clot-dissolving medication given soon after ischemic stroke onset to restore blood flow; it requires strict eligibility screening because bleeding risk is significant.

Medication that suppresses abnormal brain electrical activity to prevent seizures; adherence, side-effect monitoring, and safe withdrawal planning are essential nursing responsibilities.

How a drug is absorbed, distributed, metabolized, and eliminated by the body; these processes determine onset, duration, and needed dose adjustments in neurological patients.

Measures such as swallowing screening, upright positioning, and texture-modified diet used to prevent food or fluid from entering the airway when neurological disease impairs swallowing.

Environmental and nursing actions, including bed alarms, nonslip footwear, and assisted ambulation, that reduce injury in patients with weakness, imbalance, or altered awareness.

Safety measures for patients at risk of seizures, such as padded side rails, ready suction and oxygen, and prompt removal of hazards, aiming to prevent injury during an event.

A structured evaluation of consciousness, pupils, motor and sensory function, reflexes, and vital signs performed at intervals to detect change and guide timely intervention.