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Glossary of Physiology Terms
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There are 5 glossary search results for:   The pressure or force fluid back into the capillary




Definition:
Pulse pressure is defined as the arithmetic difference between the systolic pressure (the highest blood pressure) and the diastolic pressure (the lowest blood pressure) recorded at any point along the vascular bed. Therefore:

Pulse pressure = Systolic pressure - Diastolic pressure

Pulse pressure values can be reported at any point along the vasculature starting from the left ventricle and aorta all the way to the vena cava and the right atrium. As with systolic and diastolic pressure values, pulse pressure is typically reported in mm Hg (millimeters of mercury). A typical arterial pulse pressure is 40 mm Hg (120 - 80 = 40 mm Hg). This value decreases as one proceeds along the vascular bed from arteries to arterioles, capillaries, venules, and veins. The most significant drop occurs along the arterioles.

See also:
Mean Arterial Pressure Calculator



Definition:
The large blood vessel (artery) that receives the output of the left ventricle of the heart. The aorta is the first and largest (in diameter) artery of the systemic circulation.

Following ventricular contraction (systole), hydrostatic pressure within the ventricle exceeds the pressure in the aorta, which forces blood out of the left ventricle, through the aortic semilunar valve, and into the aorta. As the ventricle relaxes during diastole, the pressure within the left ventricle drops to a level below that in the aorta. At this point, the aortic semilunar valve closes, which prevents the backflow of blood from the aorta to the left ventricle.



Definition:
The ability of a tissue or organ to regulate its own function without extrinsic neural or hormonal input.

For example, in the kidneys, autoregulation ensures relatively constant blood flow and pressure through the kidney tubules in order to maintain a fairly constant glomerular filtration rate (GFR).



Definition:
The tapping sounds heard through a stethoscope placed over a partially compressed peripheral artery.

For the purpose of non-invasive blood pressure measurements, the stethoscope is usually placed on the skin overlying the brachial artery just distal to an inflated pressure cuff wrapped around the upper arm. As the pressure cuff is gradually deflated, the Korotkoff sounds result from the pulsations of the blood through the partially constricted brachial artery. With each ventricular systole, blood is forced to flow through the partially constricted brachial artery, and the turbulence in blood flow leads to the generation of the Korotkoff sounds. When the pressure cuff is fully deflated, flow through the artery resumes its normal laminar flow and, at that time, the Korotkoff sounds disappear.



Definition:
A rectangular signal waveform used in physiological studies to perturb (i.e., challenge) the system under study. The response of the system to the pulse is then studied carefully to learn about how the system responds to challenges.

Examples include pulses of voltage or current in electrophysiological experiments. Other examples include pulses of light, pressure, temperature, ligand, etc.

A square-wave pulse is defined by the amplitude and duration of the pulse, as well as by the frequency at which the pulse is applied to the system under study.

See also:
Neuronal Action Potential - Introduction

Other resources:
Square wave (Wikipedia)









Posted: Sunday, March 31, 2013
Last updated: Friday, August 28, 2015