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An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries. [1] Arterioles have muscular walls (usually only one to two layers of smooth muscle cells) and are the primary site of vascular resistance. The greatest change in blood pressure and velocity of blood flow ...
In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. [1] [2] It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels (from Greek kardia meaning heart, and Latin vascula meaning vessels).
A capillary is a small blood vessel, from 5 to 10 micrometres in diameter, and is part of the microcirculation system. Capillaries are microvessels and the smallest blood vessels in the body. They are composed of only the tunica intima (the innermost layer of an artery or vein), consisting of a thin wall of simple squamous endothelial cells. [2]
Metarterioles connect arterioles and capillaries. A tributary to the venules is known as a thoroughfare channel. [citation needed] The microcirculation has three major components: pre-capillary, capillary, and post-capillary. In the pre-capillary sector, arterioles, and precapillary sphincters participate. Their function is to regulate blood ...
This is a list of arteries of the human body. The aorta; The arteries of the head and neck. The common carotid artery. The external carotid artery; The triangles of the neck; The internal carotid artery; The arteries of the brain; The arteries of the upper extremity The subclavian artery; The axilla. The axillary artery; The brachial artery ...
The smaller arteries and arterioles have higher resistance, and confer the main blood pressure drop across major arteries to capillaries in the circulatory system. Illustration demonstrating how vessel narrowing, or vasoconstriction, increases blood pressure. In the arterioles blood pressure is lower than in the major arteries.
The aorta is a large artery that branches into many smaller arteries, arterioles, and ultimately capillaries. In the capillaries, oxygen and nutrients from blood are supplied to body cells for metabolism, and exchanged for carbon dioxide and waste products. [8]
Post-capillary venules are the smallest of the veins with a diameter of between 10 and 30 micrometres (μm). When the post-capillary venules increase in diameter to 50μm they can incorporate smooth muscle and are known as muscular venules. [1] Veins contain approximately 70% of total blood volume, while about 25% is contained in the venules. [2]