What does arteriole mean?
An arteriole is one of the smallest branches of the arterial system — a tiny blood vessel that carries blood from the arteries toward the capillaries, where exchange of oxygen, nutrients, and waste takes place. Although microscopic in scale, arterioles play an outsized role in human physiology: their walls contain smooth muscle that can contract or relax, narrowing or widening the vessel and thereby controlling how much blood reaches individual organs and tissues. Because this adjustable resistance directly influences total blood pressure, arterioles are central to cardiovascular medicine, and drugs such as antihypertensives often work by relaxing them. The term appears most often in anatomy textbooks, clinical research, and medical writing, typically in phrases like 'arteriolar resistance' or 'afferent arteriole'. Understanding arterioles means understanding how the fine-tuning of circulation happens far below the level of the heart itself.
nounA very small branch of an artery that leads into capillaries, regulating blood flow into body tissues by constricting or dilating.
- Anatomy: any of the smallest branches of an artery, immediately preceding the capillaries, whose muscular walls allow regulation of blood flow into tissues.
"The doctor explained that narrowed arterioles were raising the patient's blood pressure."
"Constriction of the afferent arteriole reduces the rate of filtration in the kidney's glomerulus."
"Persistent high blood pressure can cause the muscular walls of small arterioles to thicken over time."
Standard English plural; used when referring to multiple small arterial vessels or the class as a whole.
"Arterioles throughout the body dilated in response to the medication."
Barely visible to the naked eye, arterioles are the body's adjustable faucets — tightening or relaxing to control your entire blood pressure.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of arteriole
Arteriole derives from the Latin 'arteria', meaning artery, which itself was borrowed from Greek 'artēria'. It was formed with the French diminutive suffix '-ole', indicating a smaller version of the parent structure, and entered English scientific vocabulary in the early nineteenth century as anatomists refined the classification of blood vessels. It shares its root with related terms such as 'arterial', 'arteriosclerosis', and 'arteritis', all built on the same classical stem.
How arteriole is actually used
Arteriole is a technical term used chiefly in anatomy, physiology, and medicine; it rarely appears outside scientific or clinical writing. The adjective form 'arteriolar' is common in medical literature (e.g., 'arteriolar resistance').
Easily confused with arteriole
An artery is a large blood vessel carrying blood away from the heart, while an arteriole is its much smaller terminal branch leading into capillaries.
A capillary is a microscopic vessel where gas and nutrient exchange occurs, whereas an arteriole is slightly larger and controls blood flow into capillaries.