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For this reason, the blood flow velocity is the fastest in the middle of the vessel and slowest at the vessel wall. In most cases, the mean velocity is used. [18] There are many ways to measure blood flow velocity, like videocapillary microscoping with frame-to-frame analysis, or laser Doppler anemometry. [19]
Modalities applied to measurement of ejection fraction is an emerging field of medical mathematics and subsequent computational applications. The first common measurement method is echocardiography, [7] [8] although cardiac magnetic resonance imaging (MRI), [8] [9] cardiac computed tomography, [8] [9] ventriculography and nuclear medicine (gated SPECT and radionuclide angiography) [8] [10 ...
Perfusion is measured as the rate at which blood is delivered to tissue, [2] or volume of blood per unit time (blood flow) per unit tissue mass. The SI unit is m 3 /(s·kg) [ citation needed ] , although for human organs perfusion is typically reported in ml/min/g. [ 3 ]
Hypoxemia occurs in these individuals due to increased pulmonary blood flow causing: Reduced capillary transit time due to an increased blood flow within the pulmonary capillary. Capillary transit time (tc), at rest is around 0.8s, allowing plenty of time for the diffusion of oxygen into the circulation and the diffusion of CO 2 out of the ...
Ischemia, meaning insufficient blood flow to a tissue, can also result in hypoxia in the affected tissues. This is called 'ischemic hypoxia'. Ischemia can be caused by an embolism, a heart attack that decreases overall blood flow, trauma to a tissue that results in damage reducing perfusion, and a variety of other causes.
Because blood flow to the skin can be modulated by multiple other physiological systems, the PPG can also be used to monitor breathing, hypovolemia, and other circulatory conditions. [5] Additionally, the shape of the PPG waveform differs from subject to subject, and varies with the location and manner in which the pulse oximeter is attached.
White blood cells, carried to the area by the newly returning blood, release a host of inflammatory factors such as interleukins as well as free radicals in response to tissue damage. [2] The restored blood flow reintroduces oxygen within cells that damages cellular proteins, DNA, and the plasma membrane. Damage to the cell's membrane may in ...
Cardiac physiology or heart function is the study of healthy, unimpaired function of the heart: involving blood flow; myocardium structure; the electrical conduction system of the heart; the cardiac cycle and cardiac output and how these interact and depend on one another.