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Each pulse causes the targeted chamber(s) to contract and pump blood, [3] thus regulating the function of the electrical conduction system of the heart. The primary purpose of a pacemaker is to maintain an even heart rate , either because the heart's natural cardiac pacemaker provides an inadequate or irregular heartbeat, or because there is a ...
The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to the lungs. [3] In humans , the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest , called the mediastinum .
kT (also written as k B T) is the product of the Boltzmann constant, k (or k B), and the temperature, T.This product is used in physics as a scale factor for energy values in molecular-scale systems (sometimes it is used as a unit of energy), as the rates and frequencies of many processes and phenomena depend not on their energy alone, but on the ratio of that energy and kT, that is, on E ...
[2] The American Heart Association states the normal resting adult human heart rate is 60–100 bpm. An ultra-trained athlete would have a resting heart rate of 37–38 bpm. [3] Tachycardia is a high heart rate, defined as above 100 bpm at rest. [4] Bradycardia is a low heart rate, defined as below 60 bpm at rest. When a human sleeps, a ...
CPR involves chest compressions for adults between 5 cm (2.0 in) and 6 cm (2.4 in) deep and at a rate of at least 100 to 120 per minute. [2] The rescuer may also provide artificial ventilation by either exhaling air into the subject's mouth or nose ( mouth-to-mouth resuscitation ) or using a device that pushes air into the subject's lungs ...
A heart valve is a biological one-way valve that allows blood to flow in one direction through the chambers of the heart.A mammalian heart usually has four valves. Together, the valves determine the direction of blood flow through the heart.
Human anatomy (gr. ἀνατομία, "dissection", from ἀνά, "up", and τέμνειν, "cut") is primarily the scientific study of the morphology of the human body. [1]
The heart derives from embryonic mesodermal germ layer cells that differentiate after gastrulation into mesothelium, endothelium, and myocardium.Heart induction occurs in the anterior mesoderm during gastrulation through interactions with adjacent endoderm (both extra-embryonic and definitive) mediated primarily by endogenous inhibitors of WNT signaling such as DKK1.