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While both ventilation and perfusion increase going from the apex to the base, perfusion increases to a greater degree than ventilation, lowering the V/Q ratio at the base of the lungs. The principal factor involved in the creation of this V/Q gradient between the apex and the base of the lung is gravity (this is why V/Q ratios change in ...
Sometimes, the apex beat may not be palpable, either due to a thick chest wall, or conditions where the stroke volume is reduced; such as during ventricular tachycardia or shock. The character of the apex beat may provide vital diagnostic clues: A forceful impulse indicates volume overload in the heart (as might occur in aortic regurgitation)
The heart is a muscular organ situated in the mediastinum.It consists of four chambers, four valves, two main arteries (the coronary arteries), and the conduction system. The left and right sides of the heart have different functions: the right side receives de-oxygenated blood through the superior and inferior venae cavae and pumps blood to the lungs through the pulmonary artery, and the left ...
The heart is cone-shaped, with its base positioned upwards and tapering down to the apex. [8] An adult heart has a mass of 250–350 grams (9–12 oz). [ 17 ] The heart is often described as the size of a fist: 12 cm (5 in) in length, 8 cm (3.5 in) wide, and 6 cm (2.5 in) in thickness, [ 8 ] although this description is disputed, as the heart ...
It is located on the diaphragmatic surface of the heart [1] [2] near the right margin. [2] It extends between the coronary sulcus and the (notch of [ 2 ] ) apex of the heart. It contains the posterior interventricular artery and middle cardiac vein .
The right ventricle is triangular in shape and extends from the tricuspid valve in the right atrium to near the apex of the heart. Its wall is thickest at the apex and thins towards its base at the atrium. When viewed via cross section however, the right ventricle seems to be crescent shaped.
The Purkinje fibers have a fast inherent conduction rate, and the electrical impulse reaches all of the ventricular muscle cells in about 75 ms. Since the electrical stimulus begins at the apex, the contraction also begins at the apex and travels toward the base of the heart, similar to squeezing a tube of toothpaste from the bottom.
In the coronary circulation, the posterior descending artery (PDA), also called the posterior interventricular artery (PIV, PIA, or PIVA), is an artery running in the posterior interventricular sulcus to the apex of the heart where it meets with the left anterior descending artery also known as the anterior interventricular artery.