6 Terminology of the Cardiovascular, Lymphatic, Respiratory, and Blood Systems

How to decode medical terms

Medical terms often combine word parts that describe a body structure, condition, or procedure. Recognizing these parts can provide a first-pass interpretation of unfamiliar terminology, but meanings are guides rather than guaranteed definitions. Context and a reliable reference are important when the interpretation matters.

Word-part structure and interpretation

A prefix appears at the beginning of a term and modifies its meaning. A root gives the central meaning, often naming a body part. A suffix appears at the end and commonly describes a condition, procedure, or specialty. A combining vowel, usually o, joins roots or makes a term easier to pronounce.

Use this sequence to interpret a term:

1. Find and interpret the suffix first; it often identifies the kind of term.

2. Identify the root or roots and their body-system meanings.

3. Interpret any prefix.

4. Combine the meanings into a plain-language definition, then check whether it fits the context.

For example, bradycardia combines brady- (slow), cardi (heart), and -ia (condition) to mean a condition of an abnormally slow heart rate. Angiography combines angi/o (vessel) and -graphy (process of recording or imaging) to mean imaging of blood vessels. The combining vowel is commonly omitted before a suffix beginning with a vowel: cardi/itis becomes carditis.

Not every term can be completely decoded from its parts, and a word part can have more than one meaning. Use context and a reliable reference rather than treating a literal breakdown as a complete definition.

Common prefixes, roots, and suffixes

The following word-part meanings are useful guides. Interpret each part in the context of the complete term.

• Prefixes: brady- means slow; tachy- means fast or rapid; dys- means difficult, painful, abnormal, or labored; hyper- means excessive or above normal; hypo- means deficient or below normal; a- and an- mean without or absence of.

• Cardiovascular roots: cardi/o means heart; angi/o means vessel; arteri/o and ven/o mean artery and vein; vas/o and vascul/o mean vessel.

• Lymphatic roots: lymph/o means lymph; lymphaden/o means lymph node; splen/o means spleen; thym/o means thymus.

• Respiratory roots: rhin/o and nas/o mean nose; pharyng/o means pharynx; laryng/o means larynx; trache/o means trachea; bronch/o means bronchus; pneum/o means lung or air; pulmon/o means lung.

• Blood-related roots: hemat/o and hem/o mean blood; erythr/o means red; leuk/o means white; thromb/o means clot; coagul/o means clotting.

• Suffixes: -itis means inflammation; -osis means abnormal condition; -emia means blood condition; -penia means deficiency or decrease; -megaly means enlargement; -pathy means disease; -gram means recorded image or record; -graphy means process of recording or imaging; -ectomy means surgical removal; -scopy means process of viewing with an instrument; -pnea means breathing.

Cardiovascular terminology

The cardiovascular system moves blood through the heart and vessels. Common terms include:

• Cardiomegaly combines cardi/o (heart) and -megaly (enlargement) to mean enlargement of the heart.

• Bradycardia means an abnormally slow heart rate; tachycardia means an abnormally fast heart rate.

• Angiography combines angi/o (vessel) and -graphy (imaging or recording) to mean imaging of blood vessels.

• Phlebitis combines phleb (vein) and -itis (inflammation) to mean inflammation of a vein.

Lymphatic terminology

The lymphatic system returns tissue fluid to the bloodstream and supports immune defense. Terms associated with it include:

• Lymphadenopathy combines lymphaden/o (lymph node) and -pathy (disease) to mean disease or abnormality of lymph nodes. The term alone does not establish the cause.

• Lymphedema refers to swelling associated with lymph accumulation.

• Splenectomy combines splen (spleen) and -ectomy (surgical removal) to mean surgical removal of the spleen.

Respiratory terminology

The respiratory system supports breathing and gas exchange. Its terminology includes:

• Tachypnea combines tachy- (fast) and -pnea (breathing) to mean rapid breathing.

• Dyspnea combines dys- (difficult or labored) and -pnea (breathing) to mean difficult or uncomfortable breathing.

• Bronchitis combines bronch (bronchus) and -itis (inflammation) to mean inflammation of the bronchi.

• Pneumonia is a lung-related disease term. Its meaning is not fully determined by simply translating pneum/o and a suffix.

Blood terminology

Blood transports cells and other substances throughout the body. Blood terminology often combines roots for blood, cells, color, and clotting:

• Erythrocyte combines erythr/o (red) and -cyte (cell) to mean red blood cell.

• Leukocyte combines leuk/o (white) and -cyte (cell) to mean white blood cell.

• Thrombocytopenia combines thromb/o (clot), cyt/o (cell), and -penia (decrease) to mean a low platelet count.

• Anemia is a blood-related condition commonly involving too few healthy red blood cells or too little hemoglobin. Its clinical meaning is broader than a simple literal translation.

Common abbreviations

Abbreviations save space but can be unclear without context. Common examples include:

• BP: blood pressure.

• ECG or EKG: electrocardiogram, a recording of the heart’s electrical activity.

• DVT: deep-vein thrombosis.

• CBC: complete blood count.

• RBC and WBC: red blood cell(s) and white blood cell(s).

• Hgb and Hct: hemoglobin and hematocrit.

• ABG: arterial blood gases.

• COPD: chronic obstructive pulmonary disease.

• URI: upper respiratory infection.

An abbreviation may have different meanings in different settings. When reading a chart, lab report, or instruction, confirm its meaning from the surrounding context or an authoritative reference rather than guessing.