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Tag Archives: Afterload

Afterload and Its Components


Afterload Also see information about afteroad in Pharmacy Profession Forum at Afterload in the intact heart reflects the resistance that the ventricle must overcome to empty its contents. It is more formally defined as the ventricular wall stress that develops during systolic ejection. Wall stress (σ), like pressure, is expressed as force per unit area […]

Physiologic Adapations and Maladaptations in Heart Failure


Basic Concepts Preload The concept of preload in the intact heart was described by physiologists Frank and Starling a century ago. The preload can be though of as the amount of myocardial stretch at the end of diastole, just before contraction. Measurements that correlate with myocardial stretch, and that are often used to indicate the […]

The Regulation of Circulation (Heart, Neurohormons, Local)


Heart is innervated by both sympathetic and parasympathetic divisions of the autonomic nervous system. Release of norepinephrine from postganglionic sympathetic nerves activates β1-adrenoceptors in the heart, notably on the sion-atrial (SA) node, atrioventricular (AV) node, His-Purkinje conductive tissue, and atrial and ventricular contractile tissue. In response to stimulation of sympathetic nerves, the heart rate (chronotropy), rate of […]