Word Roots

alveol- = a cavity (alveoli: one of the dead-end, multilobed air sacs that constitute the gas exchange surface of the lungs)

atrio- = a vestibule; -ventriculo ventricle (atrioventricular node: a region of specialized muscle tissue between the right atrium and right ventricle; it generates electrical impulses that primarily cause the ventricles to contract)

cardi- = heart; -vascula = a little vessel (cardiovascular system: the closed circulatory system characteristic of vertebrates)

counter- = opposite (countercurrent exchange: the opposite flow of adjacent fluids that maximizes transfer rates)

endo- = inner (endothelium: the innermost, simple squamous layer of cells lining the blood vessels; the only constituent structure of capillaries)

erythro- = red; -poiet = produce (erythropoietin: a hormone produced in the kidney when tissues of the body do not receive enough oxygen. This hormone stimulates the production of erythrocytes)

fibrino- = a fiber; -gen = produce (fibrinogen: the inactive form of the plasma protein that is converted to the active form fibrin, which aggregates into threads that form the framework of a blood clot)

hemo- = blood; -philia = loving (hemophilia: a human genetic disease caused by a sex-linked recessive allele, characterized by excessive bleeding following injury)

leuko- = white;

-cyte = cell (leukocyte: a white blood cell)

myo- = muscle (myoglobin: an oxygen-storing, pigmented protein in muscle cells)

para- = beside, near (parabronchi: the sites of gas exchange in bird lungs; they allow air to flow past the respiratory surface in just one direction)

pluri- = more, several; -potent = powerful (pluripotent stem cell: a cell within bone marrow that is a progenitor for any kind of blood cell)

pulmo- = a lung; -cutane = skin (pulmocutaneous: the route of circulation that directs blood to the skin and lungs)

semi- = half; -luna = moon (semilunar valve: a valve located at the two exits of the heart, where the aorta leaves the left ventricle and the pulmonary artery leaves the right ventricle)

thrombo- = a clot (thrombus: a clump of platelets and fibrin that block the flow of blood through a blood vessel)

©2005 Pearson Education, Inc., publishing as Benjamin Cummings