U Wave Inversion

ECG abnormality linked to hypokalemia.

ECG

U-Shaped Curve

Relationship where extremes of variable increase risk.

Sociology / Exercise Physiology

UV Index

Measure of UV radiation risk to skin.

Physiology

UV Therapy

Controlled UV light for skin conditions.

Medicine

Ulcer

Open sore in skin or mucous membrane.

Pathophysiology

Ulcerative Colitis

Chronic inflammatory bowel disease.

Pathophysiology

Ulna

Forearm bone on the little finger side.

Anatomy

Ulnar Deviation

Wrist movement toward little finger.

Biomechanics

Ulnar Nerve

Nerve running along forearm into hand.

Anatomy

Ultradian Rhythm

Biological cycle shorter than 24 hours.

Physiology

Ultrafiltration

Kidney process filtering blood plasma.

Physiology

Ultrasound

Imaging using high-frequency sound waves.

Medicine

Ultrastructural Pathology

Disease signs visible only by electron microscopy.

Pathophysiology

Ultrastructure

Fine detail of cells seen with electron microscope.

Biology

Ultraviolet Radiation (UV)

Electromagnetic radiation beyond visible light.

Physics

Umbilical Cord

Structure connecting fetus to placenta.

Anatomy

Unconditioned Reflex

Innate reflex present at birth.

Motor Behavior / Physiology

Unconscious Mind

Freud’s concept of hidden mental processes.

Psychology

Uncoupling Protein

Mitochondrial protein regulating energy efficiency.

Physiology

Undertraining

Insufficient stimulus for adaptation.

Exercise Physiology

Undulating Periodization

Training model alternating volume/intensity.

Strength & Conditioning

Unequal Pupils (Anisocoria)

Condition where pupils differ in size.

Pathophysiology

Unilateral Training

Exercise using one limb at a time.

Strength & Conditioning

Unipolar Neuron

Neuron with a single process.

Anatomy / Neuroscience

Unison Response

Simultaneous activation of multiple units.

Motor Behavior

Unit Load

Biomechanical measure of stress distribution.

Biomechanics

Universal Donor

Blood group O negative used in emergencies.

Medicine

Universal Recipient

Blood group AB positive receiving all types.

Medicine

Unsaturated Fatty Acids

Healthy fats with one or more double bonds.

Nutrition

Unstable Angina

Chest pain due to coronary artery disease.

Pathophysiology

Unstable Equilibrium

State where small disturbance causes loss of balance.

Physics / Biomechanics

Unstable Fracture

Bone break with high risk of displacement.

Sport Injury

Unstable Plaque

Vulnerable atherosclerotic lesion risk for rupture.

Pathophysiology

Unstable Shoulder

Shoulder joint with excessive looseness.

Sport Injury

Unstable Vital Signs

Critical deviations in heart rate, BP, respiration.

ACLS

Untrained Individual

Person without exercise adaptation.

Exercise Physiology

Untrained Response

Initial adaptation pattern in new exercisers.

Exercise Physiology

Untreated Hypertension

Persistently high blood pressure without therapy.

Pathophysiology

Upper Airway

Nose, pharynx, larynx parts of respiratory system.

Anatomy

Upper Crossed Syndrome

Postural imbalance with rounded shoulders/forward head.

Biomechanics

Upper Esophageal Sphincter

Muscle valve controlling food entry to esophagus.

Anatomy

Upper Extremity

Arm region including shoulder, elbow, wrist, hand.

Anatomy

Upper Limb Strength Test

Measurement of arm force output.

Exercise Testing

Upper Motor Neuron

Neuron in brain/spinal cord controlling movement.

Neuroscience

Upper Motor Neuron Lesion

Damage to central motor pathways.

Pathophysiology

Upregulation

Increase in receptor number or sensitivity.

Physiology

Upright Posture

Standing body alignment against gravity.

Biomechanics

Upright Row

Resistance exercise targeting shoulders/trapezius.

Strength & Conditioning

Upstroke (ECG)

Rising phase of action potential.

ECG / Physiology

Uptake Rate (VO₂ Uptake)

Speed of oxygen consumption in exercise.

Exercise Physiology

Urban Health

Study of health outcomes in city populations.

Sociology

Urea

Waste product of protein metabolism excreted in urine.

Physiology

Uremia

Buildup of urea in blood from kidney failure.

Pathophysiology

Ureter

Tube carrying urine from kidney to bladder.

Anatomy

Urethra

Tube carrying urine from bladder to outside.

Anatomy

Urethritis

Inflammation of the urethra.

Pathophysiology

Urge Incontinence

Sudden, strong urge to urinate.

Pathophysiology

Urgent Care

Immediate medical attention for acute issues.

Medicine

Urinalysis

Laboratory analysis of urine composition.

Medicine

Urinary Biomarker

Molecule in urine indicating disease state.

Medicine

Urinary Bladder

Organ storing urine.

Anatomy

Urinary Catheterization

Insertion of tube to drain urine.

Medicine

Urinary Diversion

Surgical rerouting of urine flow.

Medicine

Urinary Retention

Inability to empty bladder fully.

Pathophysiology

Urinary System

System of kidneys, ureters, bladder, urethra.

Anatomy

Urinary Tract Infection (UTI)

Infection of bladder, urethra, or kidneys.

Pathophysiology

Urinary Urgency

Strong sudden need to urinate.

Pathophysiology

Urinary Volume

Total urine produced in given time.

Physiology

Urination (Micturition)

Process of expelling urine.

Physiology

Urine Osmolality

Measure of urine concentration.

Physiology

Urine Specific Gravity

Test indicating kidney concentrating ability.

Medicine

Urobilinogen

Compound formed from hemoglobin breakdown, found in urine.

Biochemistry

Urokinase

Enzyme used to dissolve blood clots.

Medicine

Urolith (Stone)

Solid crystal deposit in urinary tract.

Pathophysiology

Urolithiasis

Formation of stones in urinary tract.

Pathophysiology

Urology

Medical field studying urinary system.

Medicine

Urothelial Carcinoma

Cancer of bladder lining.

Pathophysiology

Urothelium

Epithelial lining of urinary tract.

Anatomy

Urticaria (Hives)

Allergic skin reaction with raised welts.

Pathophysiology

Usability

Ease of use in testing/exercise equipment.

Exercise Testing / Sociology

Use-Dependence

Drug action depending on frequency of use.

Physiology

Usher Syndrome

Genetic disorder causing deafness and blindness.

Genetics / Pathophysiology

Uterine Artery

Blood vessel supplying uterus.

Anatomy

Uterine Contractions

Muscle contractions during labor.

Physiology

Uterine Prolapse

Downward displacement of uterus.

Pathophysiology

Uterine Tube (Fallopian Tube)

Tube transporting egg to uterus.

Anatomy

Uterotonic Agent

Drug stimulating uterine contractions.

Medicine

Uterus

Female organ supporting pregnancy.

Anatomy

Utilitarianism

Ethical theory based on greatest good.

Sociology / Psychology

Utilization Time

Period over which energy substrates are used.

Exercise Physiology

Utricle

Vestibular organ detecting linear acceleration.

Anatomy

Uvea

Pigmented layer of the eye (iris, ciliary body, choroid).

Anatomy

Uveitis

Inflammation of uveal tract in eye.

Pathophysiology

Uveodermatologic Syndrome

Autoimmune condition affecting eyes and skin.

Pathophysiology

Uvula

Small projection at back of throat.

Anatomy

Uvulitis

Inflammation of the uvula.

Pathophysiology