NS LM3 flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Resting membrane potential

The voltage across a neuron membrane at rest, about -70 mV, maintained by the sodium-potassium pump and selective potassium permeability.

Saltatory conduction

Rapid propagation of action potentials by jumping between nodes of Ranvier along myelinated axons, increasing conduction velocity compared with unmyelinated fibers.

Blood-brain barrier

A selective barrier formed by tight junctions between capillary endothelial cells, astrocytes, and pericytes that restricts entry of many substances into brain tissue.

Sympathetic nervous system

The fight-or-flight division that increases heart rate, dilates pupils and bronchi, and reduces gastrointestinal activity through norepinephrine release.

Cerebellar lesion signs

Ipsilateral ataxia, dysmetria, intention tremor, and nystagmus caused by damage to the cerebellum or its connections, reflecting impaired coordination and balance.

Broca area

A region in the dominant frontal lobe that controls speech production; damage causes expressive aphasia with halting speech but preserved comprehension.

Wernicke area

A region in the dominant temporal lobe responsible for language comprehension; damage causes receptive aphasia with fluent but meaningless speech.

Basal ganglia function

A group of deep nuclei that initiate and modulate voluntary movement; dopamine loss in the substantia nigra produces Parkinsonism.

Corticospinal tract

A descending motor pathway that decussates in the medulla and carries voluntary movement commands; upper motor neuron lesions cause contralateral weakness and hyperreflexia.

Glasgow Coma Scale

A 3-15 score combining eye, verbal, and motor responses; a score of 8 or less indicates severe impairment and risk of airway compromise.

Pupillary light reflex

Constriction of the pupil in response to light, mediated by the optic nerve as afferent and the oculomotor nerve as efferent; a fixed dilated pupil suggests herniation.

Babinski sign

Dorsiflexion of the great toe with fanning of other toes after stroking the sole; abnormal in adults and indicates an upper motor neuron lesion.

Decerebrate posturing

Extension of arms and legs with internal rotation in response to painful stimuli, indicating a lower brainstem lesion and a poorer prognosis than decorticate posturing.

NIH Stroke Scale

A 0-42 standardized assessment of stroke severity covering consciousness, gaze, visual fields, motor function, sensation, language, and neglect; higher scores mean greater deficit.

Ischemic stroke window

Intravenous thrombolysis is generally given within 4.5 hours of last known well; thrombectomy may be offered up to 24 hours in selected large-vessel occlusion.

Status epilepticus

Continuous seizure activity lasting 5 minutes or longer, or repeated seizures without recovery between them; treated first with a benzodiazepine.

Myasthenia gravis

An autoimmune disorder with antibodies against acetylcholine receptors causing fatigable weakness, ptosis, and diplopia that worsen with activity and improve with rest.

Guillain-Barré syndrome

An acute immune-mediated polyneuropathy causing ascending symmetric weakness with areflexia, often after infection; respiratory function requires close monitoring.

Cushing triad

A late sign of raised intracranial pressure consisting of hypertension with widened pulse pressure, bradycardia, and irregular respirations.

Non-contrast head CT

The first-line imaging study for acute stroke and head trauma because it rapidly detects acute hemorrhage, though early ischemia may not be visible.

Lumbar puncture findings

In bacterial meningitis, cerebrospinal fluid shows elevated white cells with neutrophil predominance, high protein, and low glucose; normal opening pressure is 10-20 cm water.

Electroencephalogram

A recording of brain electrical activity used to detect seizures; continuous monitoring identifies nonconvulsive seizures in unresponsive patients.

Nerve conduction studies

Tests that measure electrical conduction velocity along peripheral nerves and help distinguish neuropathy from myopathy when combined with electromyography.

Levodopa/carbidopa

The most effective treatment for Parkinson disease; carbidopa blocks peripheral conversion of levodopa, reducing nausea and increasing delivery to the brain.

Thrombolytic exclusions

Conditions that prevent alteplase or tenecteplase in stroke, including intracranial hemorrhage, uncontrolled blood pressure above 185/110 mmHg, and recent major surgery.

Pyridostigmine

An acetylcholinesterase inhibitor that increases acetylcholine at the neuromuscular junction and reduces fatigable weakness in myasthenia gravis.

Triptan contraindications

Triptans are avoided in coronary artery disease, uncontrolled hypertension, and certain vascular disorders because of their vasoconstrictive effects.

Mannitol use

An osmotic diuretic that draws fluid from brain tissue to lower intracranial pressure; requires monitoring of osmolality, renal function, and fluid balance.

Aspiration precautions

Measures after stroke such as elevating the head of the bed, screening swallowing before oral intake, and using thickened liquids to prevent aspiration pneumonia.

Seizure safety

Do not restrain a seizing patient; protect the head, clear the area, place the patient on the side after the seizure, and time the event.

Last known well

The time a patient was last observed at neurologic baseline; it determines eligibility for thrombolysis and thrombectomy and must be documented.

SBAR handoff

A structured communication format covering situation, background, assessment, and recommendation, used to report changes in neurologic status clearly and safely.