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Oct 30, 2023 · The sudden change in the pressure gradient results in a small backflow of blood into the left ventricle just before the aortic valves close. This is represented on the aortic pressure graph by a sharp decline or ‘ incisura ’ and then a sharp increase.
- Content Manager
- 15 min
- Introduction
- Structure of The Heart
- The Cardiac Cycle
- Wigger’s Diagram
- Cardiac Volumes
- Key Points
- References
The heart is the pump of the body’s circulatory system. It must work in a systematic way so that the body is adequately supplied with blood. This article will give an overview of the cardiac cycle, highlighting the physiology and clinical relevance.
Blood flows through the structures of the heart in the following order: 1. Great veins (the venae cavae on the right and the pulmonary vein on the left) 2. Atria 3. Ventricles 4. Great arteries (the pulmonary artery on the right and the aorta on the left) There are two sets of valves, theatrioventricular and thesemilunar valves, on each side of the...
The heart relies on its muscle to contract and relax to pump the blood around the body. The left and right sides of the heart areindependent of each other, however, will contract synchronously. When in a contractile state, this is called systole. When in a relaxed state, this is called diastole. The cycle can then be divided into three stages: 1. A...
Wigger’s diagram is used to demonstrate thevarying pressures in the atrium, ventricle, and artery during one cardiac cycle (Figure 2). Intracardiac pressures are different within the right and left sides of the heart. The left side hashigher pressure, as it has to pump blood through the whole body, compared to the right side, which has to pump bloo...
There are two cardiac volumes to be measured during the cardiac cycle. 1. Ventricular end-systolic volume= the volume of blood in the ventricle at the end of the systolic phase 2. Ventricular end-diastolic volume= the volume of blood in the ventricle at the end of the diastolic phase These volumes can then be used to calculate other parameters whic...
The cardiac cycle can be divided into systolic (contraction) and diastolic(relaxation) phases.The cycle goes in the following order: atrial systole, ventricular systole and diastole.Heart valves open when the pressure of the chamber lying before it is higherthan that of the chamber after the valve.The shutting of the valves produces the two heart sounds(S1/S2), also known as the ‘lub-dub’ heart sounds.Reference texts
1. Gillian Pocock, Christopher D. Richards, David A. Richards. Human Physiology (Fifth Edition). 2018. 2. Walter F. Boron, Emile L. Boulpaep. Medical Physiology (Third Edition). 2017.
Reference images
1. Figure 1. OpenStax. Dual System of the Human Blood Circulation. License: [CC BY 4.0] 2. Figure 2 – 6. DanielChangMD. Adapted by Geeky Medics. Wigger’s diagram. Licence: [CC BY-SA 2.5]
Oct 30, 2023 · Being the first segment of the systemic circulation, the aorta originates directly from the heart. It begins from the aortic orifice found at the base of the left ventricle. It is separated from the ventricle by the aortic valve, that consists of three semilunar cusps; the right, left and posterior cusp.
- Content Manager
- 11 min
Oct 1, 2020 · This step-by-step diagram provides easy notes and explanations of the cardiac cycle, blood flow through the heart in order, and the atrial and ventricular anatomy of the heart. Learn the conduction system including the SA node, AV node, and cardiac action potentials.
When pressure within the ventricles drops below pressure in both the pulmonary trunk and aorta, blood flows back toward the heart, producing the dicrotic notch (small dip) seen in blood pressure tracings. The semilunar valves close to prevent backflow into the heart.
- Lindsay M. Biga, Sierra Dawson, Amy Harwell, Robin Hopkins, Joel Kaufmann, Mike LeMaster, Philip Mat...
- 2019
Nov 7, 2024 · The ventricles work in close coordination with the heart’s atrioventricular (AV) valves and semilunar valves to ensure the proper direction of blood flow:. Atrioventricular (AV) Valves:The tricuspid valve (in the right ventricle) and the mitral valve (in the left ventricle) are responsible for ensuring one-way blood flow from the atria to the ventricles during diastole (the heart’s ...
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From the atria, the blood flows into the lower chambers of the heart: the left ventricle, which pumps oxygenated blood to all our organs and tissues via the aorta; and the right ventricle, which pumps the deoxygenated blood back to the lungs via the pulmonary arteries.
