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The frontal sinuses are one of the four pairs of paranasal sinuses that are situated behind the brow ridges. Sinuses are mucosa -lined airspaces within the bones of the face and skull. Each opens into the anterior part of the corresponding middle nasal meatus of the nose through the frontonasal duct which traverses the anterior part of the ...
Heart failure is caused by chronic oxygen deprivation due to reduced blood flow, which weakens the heart over time. Arrhythmias are caused by inadequate blood supply to the heart that interferes with the heart's electric impulse. The coronary arteries can constrict as a response to various stimuli, mostly chemical. This is known as a coronary ...
The right coronary sulcus begins anteriorly and superiorly on the sternocostal surface of the heart. Its position is marked by the location of the right coronary artery , and small cardiac vein . The right coronary sulcus separates the right atrium and its atrial appendage from the right ventricle inferiorly.
Coronary arteries supply blood to the myocardium and other components of the heart. Two coronary arteries originate from the left side of the heart at the beginning (root) left ventricle . There are three aortic sinuses (dilations) in the wall of the aorta just superior to the aortic semilunar valve.
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).
Coronary arteries are vessels supplying blood and nutrients to the heart muscle (). [1]Coronary arteries arise from ostia, openings of the aorta (the largest artery in the human body) at the upper third or middle third of the sinuses of Valsalva (the first part of the big pipe coming off the main pumping chamber).
The externa, alternatively known as the tunica adventitia, is composed of collagen fibers and elastic tissue—with the largest arteries containing vasa vasorum, small blood vessels that supply the walls of large blood vessels. [3] Most of the layers have a clear boundary between them, however the tunica externa has a boundary that is ill-defined.
There are generally three aortic sinuses, one anterior and two posterior sinuses. These give rise to coronary arteries: [4] [better source needed] The left aortic or left posterior aortic sinus gives rise to the left coronary artery; The right aortic or anterior aortic sinus gives rise to the right coronary artery;