High Blood Pressure (Hypertension)

High Blood Pressure (Hypertension): Glossary

Here are definitions of medical terms related to high blood pressure.

ACE: Angiotensin-converting enzyme; an enzyme that causes inactive angiotensin I to be converted to active angiotensin II; also known as kinase II

ACEI or ACE inhibitors: Other terms for angiotensin-converting enzyme inhibitors

Acute: brief; short term

Adrenal gland: A gland that is at the upper end of each kidney; it is a ductless glands that secretes catecholamines (epinephrine and norepinephrine) from the medulla portion of the gland and steroid hormones (such as cortisol) from the cortex portion of the gland

Adrenal gland tumors: Tumors (abnormal tissue growth characterized by the rapid growth and reproduction of cells with a lack of structural organization) that affect the adrenal gland

Adrenergic: Refers to the catecholamines, epinephrine and norepinephrine

Adverse effects: Any undesirable or unwanted consequences of a drug or a preventive, diagnostic, or therapeutic procedure

Aerobic physical activity: Physical activity that increases the heart rate

Aldosterone: Hormone secreted from the adrenal cortex that causes sodium absorption (with secondary water reabsorption) in the kidneys (in other words, it increases the volume of circulating blood)

Angina: Pressure, tightness, or constricting pain in the chest that occurs due to inadequate blood flow to heart muscle; is usually associated with significant coronary artery disease

Angioedema: Type of swelling involving the face and airways that is related to allergy

Angiotensin II: A potent vasoconstrictor and growth-promoter produced by the RAAS following stimulation by renin; also triggers the release of vasopressin (a pituitary hormone that affects vascular tone and body fluid levels)

Angiotensin: Converting enzyme (ACE): enzyme that causes inactive angiotensin I to be converted to active angiotensin II

Angiotensin-converting enzyme inhibitors (ACEI): Agents used in the treatment of mild-to-moderate hypertension, congestive heart failure, myocardial infarction, and diabetic nephropathy. Their mechanism of action involves blocking the enzyme that converts angiotensin I to angiotensin II (ACE), thus reducing the availability of angiotensin II.

Angiotensin II receptor blockers: A new class of antihypertensive agents; their mechanism of action involves the site-specific blockade of certain angiotensin II receptors

Antidiuretic hormone: Hormone that decreases the excretion of urine (i.e., retains water in body) and also causes contraction of smooth muscle in arteries (vasoconstriction); also referred to as vasopressin.

Antihypertensive medication: A drug that is intended to reduce the blood pressure of individuals with high blood pressure

Aorta: Large artery of the elastic type that is the main trunk of the systemic arterial system

Arteries: Blood vessels that carry blood away from the heart

Arterioles: Small arteries

Arteriosclerosis: A condition involving arterial (or vascular) sclerosis or hardening of the vessels

Artery: Blood vessel that carries blood away from the heart

AT1 receptors: A subtype of angiotensin II receptor thought to mediate the effects of angiotensin II (i.e., vasoconstriction, promotion of growth)

AT2 receptors: A subtype of angiotensin II receptors thought to mediate actions of angiotensin II that oppose actions mediated by AT1 receptors

Atria: Upper cavities or chambers of the right and left sides of the heart; singular is “atrium”

Atherosclerosis: Represents a form of arteriosclerosis characterized by irregularly distributed fatty deposits and fibrous tissue in the inner layer of large- and medium-sized vessels, causing narrowing of the blood vessel

Atheromatous plaques: Also called “atheromas” or just “plaques;” refers to lesions associated with atherosclerosis; these lesions form due to the deposition of fatty substances and fibrous tissue and lead to the narrowing and hardening of arteries

Autonomic nervous system (ANS): The motor division of the peripheral nervous system that supplies nerve fibers to smooth muscle, cardiac muscle, and glands

Baroreceptors: Stretch receptors located within the cardiovascular system that detect changes in blood pressure and transmit this information to the central nervous system

Beta-adrenergic blocking agents (beta-blockers): A class of drugs that is frequently used to begin treatment for hypertension and is also used to treat cardiac arrhythmias (abnormal heart rhythms) and coronary artery disease.

Beta1 receptors: Adrenergic receptors that bind the hormones norepinephrine (noradrenaline) and epinephrine (adrenaline); includes Beta 1 and Beta 2 subtypes that regulate heart rate, myocardial contractility, and vascular tone (tension in blood vessels)

Beta1 receptors: A subtype of adrenergic receptors (and beta receptors) that mediates heart rate and myocardial contractility

Blood flow: Movement of blood through blood vessels

Blood pressure (BP): The force per unit area exerted on the wall of a blood vessel by the blood it contains

Blood pressure measurements: Measurements of blood pressure, usually expressed as the systolic blood pressure over the diastolic pressure

Blood vessel: A term for a tube conveying blood, which may be used to describe an artery, capillary, vein, or sinus

Blood vessel length: Linear distance between the ends of a blood vessel

Blood vessel diameter: The width of a blood vessel

Blood viscosity: Viscosity refers to the resistance to flow or alteration in shape of a liquid; blood viscosity is a measure of the thickness of “stickiness” of blood, which reflects the number of circulating blood cells among other factors

Blood volume: Amount of blood circulating in body

Brachial pulse: The pulse (rhythmical dilation of an artery, produced by the increased volume of blood that enters a vessel with cardiac contraction) that can felt over the brachial artery (an artery extending from about the level of the shoulder to the elbow)

Bradycardia: Decreased heart rate (HR); usually defined as a heart rate of less than 60 beats per minute.

Bradykinin: Produced from bradykinogen under direction of the enzyme kallikren; bradykinin is an endothelium-derived substance/hormone that causes vasodilation and release of nitric oxide and prostacyclin

Bronchospasm: Spasm of lung bronchioles

Bruits: A harsh or musical, intermittent sound heard with a stethoscope; an indication on physical exam of abnormal blood flow and/or lesions (such as plaques) in blood vessels

Calcium antagonists: Another term for calcium channel blockers

Calcium channel blockers: Drugs used in the treatment of hypertension and angina; their mechanism of action involves opening up blood vessels

Cardiovascular risk factors: Risk factors for heart disease including high blood pressure, cigarette smoking, diabetes, older age, gender, and family history of cardiovascular disease, among others

Cardiac output (CO): Amount of blood pumped out of the ventricle in one minute

Catecholamines: Epinephrine (adrenaline) and norepinephrine (noradrenaline)

Central nervous system (CNS): Division of nervous system consisting of brain and spinal cord

Chronic obstructive pulmonary disease (COPD): A chronic condition involving expiratory airflow obstruction due primarily to emphysema; a frequent result of lung damage due to smoking

Clinical trials: An internationally recognized research protocol designed to evaluate the efficacy or safety of drugs, vaccines, or other therapeutic agents, and to produce scientifically valid results

Coarctation of the aorta: Constriction of the aorta; a cause of secondary hypertension

Comorbid: Coexisting, but unrelated, pathological process or disease state

Compliance: A measure of the ease with which a structure such as an artery can be stretched

Congestive heart failure: Failure of the heart to pump blood effectively

Constrict: The act or process of binding or contracting; becoming narrowed or squeezed

Contractility: Vigor of heart-pumping action

Cortisol: Also known as hydrocortisone, cortisol is a steroid hormone that represents the most powerful glucocorticoid produced by the adrenal gland; actions include promotion of the formation of glucose from fats and proteins as well as anti-inflammatory effects

Cushing’s syndrome: Refers to a syndrome consisting of a variety of symptoms caused by the production of too much cortisol (and other hormones); a cause of secondary hypertension

Diabetes: A disorder that prevents the body from converting digested food into energy.

Diabetic nephropathy: Kidney dysfunction in an individual with diabetes

Diastolic blood pressure (DBP): The lowest level of pressure in the aorta that occurs during diastole (relaxation of ventricles); ranges between 70-80 mm Hg in normal (healthy) adults

Dilate: Enlarge the opening or the lumen of a hollow structure such as a blood vessel

Distensibility: The ability of an artery to increase in diameter; refers to the intrinsic wall properties of large vessels containing elastin

Dyslipidemia: Abnormal blood levels of lipids (substances extracted from animal or vegetable cells, including fatty acids and “fat-soluble” vitamins A, D, and E)

Edema: The accumulation of an excessive amount of watery fluid in cells, tissues, or serous cavities.

Elastic arteries: Arteries that easily distend due to elastin contained in the arterial walls

Ejection fraction: Percentage of blood contained in the ventricle that is ejected during systole (ventricular contraction)

Endothelin: The most powerful vasoconstrictor produced by the endothelium (endothelial cells lining blood vessels); also has growth-promoting effects

Endothelium: Singular layer of flat cells that lines the walls of the heart, blood vessels, and lymphatic vessels; inner lining of the tunica intima layer of blood vessels

Endothelium-derived substances: Biologically active substances released by the endothelium in response to neural and chemical stimuli; these substances are involved in the regulation of vascular tone (i.e., peripheral resistance) and structure

Endothelial dysfunction: An imbalance between the vasodilating and vasoconstricting factors and growth-inhibiting and growth-promoting factors produced by the endothelium

Epinephrine: Chief hormone produced by adrenal medulla; also referred to as ‘adrenaline’

Essential hypertension: High blood pressure of “unknown cause,” although multiple theories exist; it accounts for 90%-95% of individuals with hypertension

Friction: The act of rubbing the surface of an object against that of another

Growth inhibitors: Substances that inhibit growth; in this context, refers to substances released by the endothelium that inhibit the growth of vascular smooth muscle cells.

Growth promoters: Substances that promote growth; in this context, refers to substances released by the endothelium that promote the growth of vascular smooth muscle cells.

Heart rate (HR): Number of beats (contractions) of heart per minute

HDL cholesterol: “Good cholesterol”; high levels are thought to protect the heart

Heart failure: Inadequate pumping of the heart to maintain the forward circulation of blood, often resulting in the development of congestive heart failure and swelling in body tissues

Heredity: The transmission of characteristics from parent to offspring

Hormones: Chemical substances, formed in one organ or part of the body and carried in the blood to another organ or part

Hyperaldosteronism: A term to describe various conditions that lead to abnormally high levels of aldosterone; a cause of secondary hypertension

Hypercholesterolemia: Abnormally high serum levels of cholesterol; a risk factor for cardiovascular disease

Hypertension: High blood pressure; that is, blood pressure greater than 140/90

Hypotension: Lower-than-normal blood pressure

Inflammatory response: A chemical reactions that occur in blood vessels and nearby tissues in response to an injury or abnormal stimulation caused by a physical, chemical, or biologic agent

Insulin: A hormone secreted by the pancreas

Insulin resistance: State in which cells are resistance to effects of insulin, a hormone secreted by the pancreas

Insulin sensitivity: Sensitivity of cells to effects of insulin

Ischemia: Inadequate blood to tissue due to an obstruction (mainly a narrowing of an artery)

Isolated systolic hypertension (ISH): A systolic blood pressure (SBP) of 140 mm Hg or greater and a diastolic blood pressure (DBP) of less than 90 mm Hg; a form of blood pressure that is commonly observed in elderly individuals

JNC VI: The sixth Joint National Committee’s report on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure; published in November 1997 by the National Institutes of Health; intended to guide clinicians in the treatment of high blood pressure

LDL cholesterol: “Bad cholesterol”; high levels contribute to atherosclerosis, which clogs arteries and causes heart attacks and strokes

Left ventricular dysfunction: Refers to dysfunction of left ventricle of heart

Lipids: Substances extracted by the body from animal or vegetable cells, including fatty acids and “fat-soluble” vitamins A, D, and E

Loop diuretics: A type of diuretic less commonly used to treat hypertension

Mean arterial pressure: Static component of blood pressure equal to the cardiac output multiplied by the peripheral resistance

Mechanism of action (MOA): Used to describe the ways pharmacologic agents achieve their effects

Myocardial infarction: A heart attack

Natriuresis: Urinary excretion of sodium (accompanied by water); may be increased by disease or by taking diuretics

Nephropathy: Any disease of the kidney

Nervous system: The system in the body consisting of the brain and spinal cord (central nervous system), along with other structures

Nitric oxide (NO): A chemical messenger released by nerve fibers that can widen blood vessels

Norepinephrine (NE): Hormone released by the adrenal gland that is also a neurotransmitter (substance released by nerves); one of the two catecholamines

Organ: Any part of the body that carries out a specific function such as breathing, digestion, etc.

Osteoporosis: A condition in which the bones become weaker and are more likely to break

Peripheral pulses: Pulse that is felt away from the center of the body, such as in the legs or feet

Peripheral resistance: The body’s ability to regulate the width of the blood vessels

Plaques: When used in regard to atherosclerosis, this term fatty deposits inside blood vessels

Postmenopausal: After menopause, which refers to the time when a woman no longer has menstrual periods

Potassium-sparing diuretics: Agents used to treat patients with mild-to-moderate hypertension; their mechanism of action involves the excretion of sodium and retention of potassium by the kidneys

Primary hypertension: Another name for essential hypertension

Prostacyclin: A type of prostaglandin that causes blood vessels to widen and helps prevent clots from forming

Prostaglandins: Substances released by a number of tissues in the body; their actions include regulating smooth muscle contraction within blood vessels

Pulmonary circulation: The passage of blood from the heart to the lungs and back again

Pulse pressure: The difference between the systolic (maximum) blood pressure and diastolic (minimum) blood pressure.

Rales: A sound heard through a stethoscope that could indicate the presence of fluid within the lungs or other conditions

Red blood cells: Blood cells that carries oxygen

Renal: Pertaining to kidneys

Renal parenchymal disease: Disease affecting the parenchyma (connective tissue) of the kidneys

Renal vascular disease: Also called “renovascular disease;” includes problems with blood flow to the kidneys

Renin: An enzyme that converts angiotensinogen to angiotensin I

Renin-angiotensin system (RAS): A system of hormones and enzymes that plays an important role in regulating blood pressure and the body’s balance of fluids and electrolytes; includes angiotensin II; also known as renin-angiotensin aldosterone system (RAAS), when it includes aldosterone

Renin-angiotensin aldosterone system (RAAS): A term applied to RAS when including actions of the hormone aldosterone. The RAS is a system of hormones and enzymes that plays an important role in regulating blood pressure and the body’s balance of fluids and electrolytes

Resistance: The opposition to the flow of a fluid through one or more passageways, such as opposition to the passage of blood through a blood vessel

Secondary hypertension: High blood pressure caused by a diagnosable condition

Side effect: A result of drug or other therapy in addition to or in extension of the desired therapeutic effect; usually but not necessarily meaning an undesirable effect.

Sodium: A metallic element that is one of the body electrolytes

Stress test: Procedure used to measure the heart’s response to exercise (also known as an exercise tolerance test); the individual rides a stationary bicycle or walks on a treadmill while a machine records heart activity.

Stroke volume (SV): Amount of blood pumped out of the ventricle during one contraction (heart beat)

Systemic arteries: Arteries found in the cardiovascular system

Systemic circulation: The circulation of blood through the arteries, capillaries, and veins of the general system

Systole: Contraction of the heart, especially the ventricles

Sympathetic nervous system: A division of the autonomic nervous system that is involved in mobilizing the body in response to threatening or emergent conditions (“fight-or-flight”)

Systolic blood pressure (SBP): The peak (highest) pressure that occurs when the heart contracts; averages about 120 mm Hg in healthy adults

Target organ damage: Refers to damage to organs associated with uncontrolled high blood pressure

Thiazide diuretics: Most common class of diuretics used to treat mild hypertension

Thyroid gland: A gland in the neck that secretes hormones needed to perform certain functions within the body

Titrated: In regard to dosage, refers to the adjustment of a dose based on the response to the medication

Total peripheral resistance (TPR): The resistance to blood flow imposed by the arteries and arterioles of the peripheral (systemic) circulation; also called “peripheral resistance”

Type 1 diabetes: A condition in which the body stops making insulin

Type 2 diabetes: A condition in which the body cannot use insulin properly

Vasoconstricting: Constricting or narrowing a blood vessel

Vasoconstriction: Constriction or reduction in the diameter of a blood vessel

Vasoconstrictor: Substance that cause the narrowing of a blood vessel

Vasodilating: Dilating or widening a blood vessel

Vasodilation: Increase in the diameter of a blood vessel

Vasodilator: Substance that causes widening of a blood vessel

Veins: Blood vessel that carries blood toward the heart

Ventricles: Lower cavities or chambers of the right and left sides of the heart

White-coat hypertension: A temporary increase in blood pressure experienced by some patients in the clinical setting (such as in a doctor’s office) attributed to stress associated with having their blood pressure measured