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Medical Dictionary - Letter: h

H+hydrogen ion
h/ohistory of
habitA recurrent, often unconscious pattern of behavior that is regularly manifested.
hairA threadlike specialized epidermal structure developing from a papilla sunk in the dermis.
hair follicleA tube-like invagination of the epidermis from which the hair shaft develops and into which the sebaceous glands open. The hair follicle is lined by a cellular inner and outer root sheath of epidermal origin and is invested with a fibrous sheath derived from the dermis.
halitosisA foul breath odor resulting from poor oral hygiene, dental or oral infections, or the ingestion of certain foods.
hallucinationSensing things while awake that appear to be real, but instead have been created by the mind, common in delirium.hah-loo″sĭ-na´shun
hallux valgusA bunion. A deformity of the joint connecting the big toe to the foot.hal'ŭks val'gŭs
handThe distal part of the arm beyond the wrist consisting of the carpus, metacarpus, and fingers.
hapl/osimple, single
HAVhepatitis A virus
HBPhigh blood pressure
HBVhepatitis B virus
HCGhuman chorionic gonadotropin
HCPhealth care professional
HCVhepatitis C virus
HDhearing distance
HDLhigh-density lipoprotein
HDVhepatitis D
headThe upper part of the body containing the brain, mouth, and sense organs.
headachePain in the cranial region.
hearingThe ability to perceive sounds.
heartThe hollow, muscular organ that maintains the circulation of the blood.
heart arrestCessation of heart beat.
heart blockImpaired conduction of cardiac impulse that can occur anywhere along the conduction pathway, such as between the sinoatrial node and the right atrium (SA block) or between atria and ventricles (AV block).
heart failureA heterogeneous condition in which the heart is unable to pump sufficient blood to meet the metabolic need of the body.
heart murmursHeart sounds caused by vibrations resulting from the flow of blood through the heart.
heart septumThis structure includes the thin muscular atrial septum between the two heart atria, and the thick muscular ventricular septum between the two heart ventricles.
heart soundsThe sounds heard over the cardiac region produced by the functioning of the heart.
heart valvesFlaps of tissue that prevent regurgitation of blood from the ventricles to the atria or from the pulmonary arteries or aorta to the ventricles.
heartburnSubsternal pain or burning sensation, usually associated with regurgitation of gastric juice into the esophagus.
heat exhaustionA clinical syndrome caused by heat stress, such as over-exertion in a hot environment or excessive exposure to sun.
heat strokeA condition caused by the failure of body to dissipate heat in an excessively hot environment or during physical exertion in a hot environment. The body temperature is dangerously high with red, hot skin accompanied by delusions; convulsions; or coma. It can be a life-threatening emergency and is most common in infants and the elderly. Also called sunstroke.
hect-one hundred
heel spurA bony outgrowth on the lower surface of the heel bone.
hemangiomaA birthmark that commonly appears as a bright red nodule of blood vessels in the skin. Grows during the first year of life and then recedes over time. Also called a strawberry mark.he-man″je-o´mah
hemarthrosisBleeding into the joints.he″mahr-thro´sis
hematemesisVomiting blood.he″mah-tem´ĕ-sis
hematocolposAn accumulation of menstrual blood in the vagina.
hematocritThe percentage by volume of red blood cells in a given sample.
hematologyThe medical specialty focused on the diagnosis, treatment and prevention of blood diseases.he″mah-tol´o-je
hematomaAn abnormal collection of blood outside of a blood vessel. A bruise.he″mah-to´mah
hematometraAn accumulation of menstrual blood in the uterus.
hematospermiaBlood in the semen.he·ma·to-sper´me-ah
hematuriaRed blood cells in the urine.he″mah-tu´re-ah
hemianopiaThe loss of part of the field of view on the same side, in both eyes. A common side effect of stroke or brain injury. hem″e-ah-no´pe-ah
hemiparesisWeakness or paralysis of the entire left or right side of the body. Caused by congenital conditions, trauma, stroke or tumors.hem″e-pah-re´sis
hemiplegiaParalysis of one side of the body.hem″e-ple´jah
hemobiliaBleeding into the biliary passages.
hemochromatosisA disorder of iron metabolism where the body absorbs too much iron. Treatment is required to avoid organ damage. A genetic disorder. 8% of population is a carrier.he″mo-kro″mah-to´sis
hemodialysisA therapeutic procedure used with kidney failure involving removal of harmful wastes and fluids from the blood.he″mo-di-al´ĭ-sis
hemodynamicsThe forces involved in the movement of the blood through the cardiovascular system.
hemoglobinsThe oxygen-carrying proteins of erythrocytes (red blood cells). he´mo-glo″binz
hemopneumothoraxCollection both blood and air in the pleural cavity.
hemoptysisCoughing up blood or blood-stained mucus from the respiratory tract.he-mop´tĭ-sis
hemorrhageBleeding or escape of blood from a vessel. Bleeding can occur externally or internally to the body.hem´ŏ-rij
hemorrhagic strokeA stroke that occurs when a weakened blood vessel ruptures. Also called an aneurysm.hem″o-raj´ik
hemorrhoidsSwollen veins in the lower part of the rectum or anus.
hemospermiaBlood in the semen, often due to inflammation of the prostate or the seminal vesicles.
hemostasisThe complex body process which spontaneously stops hemorrhages. This includes vessel contraction and blood adhesion, aggregation and coagulation.he-mos´tah-sis
hemothoraxHemorrhage within the pleural cavity, often from chest trauma.he″mo-thor´aks
heparinAn endogenous, short-acting anticoagulant.
hepaticPertaining to the liver.
hepatitisInflammation of the liver caused by viral agents.hep'ă-tī'tis
hepatoblastomaA malignant neoplasm occurring in young children, primarily in the liver,
hepatocytesA parenchymal liver cell.
hepatomaA malignant tumor of the liver
hepatomegalyHaving an enlarged liver.hep″ah-to-meg´ah-le
herbicidesPesticides used to destroy vegetation, particularly weeds and grasses.
heredityThe transmission of traits encoded in genes from parent to offspring.
heredo-heir, heredity
hermaphroditicA plant or animal with both male and female sex organs.
herniaAbnormal protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained.her´ne-ah
herniorrhaphySurgical repair of a hernia
herpesAn infection caused by a herpes simplex virus. Can affect the genitals, buttocks or anal areas. Oral herpes causes cold sores on the face or mouth.her´pēz
herpes labialisCold sores caused by herpes simplex I.her´pēz lā´bēal´is
heter-different, other
heterophoriaA tendency for deviation of the eyes from parallelism, prevented by binocular vision.
heterosexualityThe sexual attraction between members of the opposite sex.
heterosisGreater vigor of the first generation hybrid than is shown by either parent.
heuristicsA set of rules or methods for solving problems other than by algorithm. The solution is not guaranteed to be optimal, but sufficient for a given set of goals.
HEVhepatitis E
HFheart failure
HFOVhigh frequency oscillatory ventilation
HGFhuman growth factor
HGSILhigh-grade squamous intraepithelial lesion
hiat/ogap, opening, pause
hiatusAn aperture, gap or opening.
hiccupA spasm of the diaphragm that causes a sudden inhalation followed by rapid closure of the glottis which produces a sound. Also called singultus.
hidrocystomaA cystic form of sweat gland adenoma, created by the cystic proliferation of apocrine secretory glands.
hidrosisThe production and excretion of sweat.
hidroticRelating to or causing sweating.
high density lipoproteinCholesterol known as HDL that removes harmful cholesterol, reducing risk of heart problems.
hipThe region of the body around the joint between the top of the femur and side of the pelvis.
HIPAAHealth Insurance Portability and Accountability Act
hippocampusA curved elevation of gray matter extending the entire length of the floor of the temporal horn of the lateral ventricle (see also temporal lobe). It has a central role in memory processes.
hippusRhythmic pupillary dilation and constriction, independent of changes in illumination or convergence.
hirsutismExcessive hairiness in women, usually caused by hormonal imbalance.her´soo-tizm
histamineAn amine found in body tissues released in allergic inflammatory reactions. It is a vasodilator, stimulant of heart rate and gastric secretion, constrictor of bronchial smooth muscle and also a centrally acting neurotransmitter.
histiocytesMacrophages found in the tissues, as opposed to those found in the blood or serous cavities.
histiocytomaA neoplasm containing histiocytes.
histiocytosisAbnormal appearance of histiocytes.
histogramA bar chart.
histologyThe study of the structure of tissues on a microscopic level.
hivHuman immunodeficiency virus.
hoarsenessAn unnaturally rough quality of voice.
Hodgkin's lymphomaA type of lymphoma, a cancer of tissue in the lymph nodes, spleen, liver, and bone marrow. The first sign is often an enlargement of lymph node.
holo-entire, complete
holographyThe recording of three-dimensional images form using a laser beams.
holter monitorA device that continuously records EKGs for hours or a few days, used to diagnose abnormal cardiac rhythms.
home/osame, not changed
homeostasisThe process of maintaining physiological equilibrium.
homosexualityThe sexual attraction or relationship between members of the same sex.
hordeolumBlockage of an eyelid gland causing a small inflamed cyst at the lid margin. Also called a stye.hor-de´o-lum
horm-impulse, urge
hormoneSubstances having a specific regulatory effect on the activity of an organ or organs.
hospiceA facility providing palliative and supportive care to a patient with a terminal illness and to the patient's family.
hospice careCare provided to a dying person. Care may be provided in the home, in the hospital or in specialized facilities.
hospitalistsPhysicians who are employed to work exclusively in hospital settings, often for managed care organizations.
HPIhistory of present illness
HRheart rate
HRThormone replacement therapy
HSILhigh-grade squamous intraepithelial lesion
HSVherpes simplex virus
humerusThe bone of the upper arm. It extends from the shoulder joint to the elbow joint.
huntington diseaseAn inherited disorder characterized by the onset of progressive chorea (involuntary, rapid, irregular, jerky movements) and dementia in middle age.
hyalinA translucent substance occurring in pathological degeneration of tissues.
hydr/owater, fluid
hydremiaAn excess of water in the blood.
hydroceleBuildup of the normal fluid around the testicle, common in infants, self-resolving.hi´dro-sēl
hydrocephalusThe buildup of excessive cerebrospinal fluid in the brain. hi″dro-sef´ah-lus
hydronephrosisAbnormal enlargement of a kidney, sometimes caused by blockage of the ureter.hi″dro-nĕ-fro´sis
hygieneThe science and practices that promote or preserve health
hymenA thin fold of mucous membrane situated at the orifice of the vagina.
hyper-excessive, above
hyperalgesiaAn abnormal increased sensation of pain, caused by damage to soft tissue containing nociceptors or injury to a peripheral nerve.
hyperbaricAt a pressure higher than atmospheric pressure.
hypercalcemiaToo much calcium in the blood.hi″per-kal-se´me-ah
hypercalciuriaExcretion of abnormally high level of calcium in the urine.
hypercapniaAbnormal increase in carbon dioxide in the blood.hī'pĕr-kap'nē-ă
hyperemesis gravidarumSevere, intractable vomiting during early pregnancy. Often needs IV fluids and anti nausea agents.hī′pər-ĕm′ĭ-sĭs grăv′ĭ-dâr′əm
hyperemiaThe presence of an increased amount of blood in a body part due to increase of blood flow into the area or due to obstruction of outflow of blood from the area.
hyperesthesiaHyperesthesia is a condition in which someone becomes highly sensitized to sensory stimuli. hi″per-es-the´zhah
hyperglycemiaHigh blood sugar. A serious problem for diabetics.hi″per-gli-se´me-ah
hyperhidrosisExcessive sweating.
hyperinsulinismAbnormally high levels of insulin in the blood. hi″per-in´su-lin-izm″
hyperkalemiaAbnormally high potassium concentration in the blood, usually due to acute renal failure.
hyperkinesiaSpontaneous involuntary movements.hy·per-kĭ-ne´zhah
hyperkinesisExcessive movement of muscles of the body.
hyperlipidemiaConditions with excess lipids (fats) in the blood. hi″per-lip″i-de´me-ah
hypernatremiaAn excess of sodium in the blood.
hyperopiaFarsightedness. Distant objects can be seen clearly, but close ones do not come into proper focus. hi″per-o´pe-ah
hyperostosisAbnormal thickening or growth of bone.
hyperoxaluriaAbnormally high amounts of oxalates in the urine.
hyperoxiaAn excess of oxygen in tissues and organs.
hyperphosphatemiaAbnormally high level of phosphates in the blood.
hyperpigmentationExcessive pigmentation of the skin, usually as a result of increased epidermal or dermal melanin pigmentation, hypermelanosis. The condition may arise from exposure to the sun.
hyperpituitarismExcessive hormone production by the pituitary gland.hi″per-pĭ-too´ĭ-tah-rizm″
hyperplasiaAn abnormal increase in the number of cells in a tissue or organ without tumor formation.
hyperpneaDeep breathing. Can be normal during exercise or abnormal due to anemia or sepsis.hi″perp-ne´ah
hypersensitivityAbnormally high response to an antigen.
hypersomniaExcessive sleeping
hyperstheniaExcessive strength or tension.
hypertensionPersistently high systemic arterial blood pressure.hy·per-ten´shun
hyperthyroidismExcessive hormone production by the thyroid. hi″per-thi´roi-dizm
hyperthyroxinemiaAbnormally elevated thyroxine level in the blood.
hypertonicHaving increased tone or tension.
hypertrichosisExcessive hair growth at inappropriate locations.
hypertriglyceridemiaA condition of elevated levels of triglycerides in the blood.
hypertrophyGeneral increase in volume of a tissue or organ produced entirely by enlargement of existing cells.
hyperuricemiaAn abnormally high concentration of uric acid in the blood. It is associated with gout and also hypertension.
hyperventilationBreathing faster or deeper than is metabolically necessary causing an excessive intake of oxygen and a reduction carbon dioxide level in arterial blood.
hypesthesiaAbsent or reduced sensitivity to cutaneous stimulation.
hyphemaBleeding in the anterior chamber of the eye.
hypnosisA state of increased receptivity to suggestion and direction, initially induced by the influence of another person.
hypo-deficient, under
hypocalcemiaAbnormally low levels of calcium in the blood.
hypocapniaDeficiency of carbon dioxide in arterial blood.
hypochondriaAnxiety about one's own health and belief that one is likely to become ill even though there is no medical evidence of illness.
hypochondriasisAn overwhelming fear of having a serious disease.hi″po-kon-dri´ah-sis
hypodermicBeneath the skin.
hypogeusiaDiminished sense of taste.
hypoglycemiaAbnormally low blood glucose (blood sugar) levels, usually less than 70 mg/dl.hi″po-gli-se´me-ah
hypogonadismAbnormally low functional activity of the gonads, with diminished growth and sexual development
hypohidrosisAbnormally low or absent perspiration.
hypokalemiaAbnormally low potassium concentration in the blood.
hypokinesiaAbnormally diminished movement of body musculature.
hypomenorrheaExtremely light menstrual blood flow.hy·po-men″o-re´ah
hyponatremiaInsufficient sodium levels in the blood. Can be caused by loss of sodium or by increased and excessive body fluids.hi″po-na-tre´me-ah
hypoperfusionAbnormally low blood flow through an organ.hy-po-per-per-fu´zhun
hypoplasiaUnderdevelopment of a tissue or organ.
hypopneaShallow or abnormally slow breathing.hi-pop´ne-ah
hypospadiasA birth defect due to malformation of the urethra in which the urethral opening is below its normal location.hi″po-spa´de-as
hypotensionAbnormally low blood pressure that can result in inadequate blood flow to the brain and other organs.hi″po-ten´shun
hypothermiaLower than normal body temperature.
hypotoniaPoor muscle tone usually detected at birth or during infancy. It is reflected in the APGAR score.hy·po-tōn´e-ah
hypotonicDenoting decreased tone or tension.
hypotrichosisLess than the normal amount of hair.
hypoventilationDeficient ventilation of the lungs resulting is low oxygen levels and high carbon dioxide levels in the blood.
hypovolemiaAn abnormally low volume of circulating blood.
hypoxemiaOxygen deficiency in arterial blood.hi″pok-se´me-ah
hypoxiaInsufficient oxygen levels in body organs and tissues.hi-pok´se-ah
hysterectomySurgical removal of the uterus. his″tĕ-rek´to-me
hysteriaExcessive or uncontrollable emotion, such as fear or panic.
hysterosalpingographyFluoroscopic examination of the uterus and fallopian tubes.hys-tero-sal″ping-gog´rah-fe
hysteroscopyExamination of the uterine cavity using an endoscope.his′təros′kepē
hysterotomyAn incision in the uterus, performed through either the abdomen or the vagina.
Hzhertz (cycles per second)