# resistance

(redirected from systemic vascular resistance)
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## resistance,

in biology: see immunityimmunity,
ability of an organism to resist disease by identifying and destroying foreign substances or organisms. Although all animals have some immune capabilities, little is known about nonmammalian immunity.
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## resistance,

in psychiatry: see psychoanalysispsychoanalysis,
name given by Sigmund Freud to a system of interpretation and therapeutic treatment of psychological disorders. Psychoanalysis began after Freud studied (1885–86) with the French neurologist J. M.
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## resistance,

property of an electric conductor by which it opposes a flow of electricity and dissipates electrical energy away from the circuit, usually as heat. Optimum resistance is provided by a conductor that is long, small in cross section, and of a material that conducts poorly. Resistance is basically the same for alternating and direct current circuits (see impedanceimpedance,
in electricity, measure in ohms of the degree to which an electric circuit resists the flow of electric current when a voltage is impressed across its terminals.
). However, an alternating current of high frequency tends to travel near the surface of a conductor. Since such a current uses less of the available cross section of the conductor than a direct current, it meets with more resistance than a direct current. In circuit analysis an ideal resistorresistor,
two-terminal electric circuit component that offers opposition to an electric current. Resistors are normally designed and operated so that, with varying levels of current, variations of their resistance values are negligible (see resistance).
, i.e., a circuit component whose only property is resistance, is called a resistance. The phenomenon of resistance arises from the interactions of electrons with ions in the conductor. The unit of resistance is the ohmohm
[for G. S. Ohm], symbol Ω, unit of electrical resistance, defined as the resistance in a circuit in which a potential difference of one volt creates a current of one ampere; hence, 1 ohm equals 1 volt/ampere. The megohm (1,000,000 ohms) and the milliohm (.
. See superconductivitysuperconductivity,
abnormally high electrical conductivity of certain substances. The phenomenon was discovered in 1911 by Heike Kamerlingh Onnes, who found that the resistance of mercury dropped suddenly to zero at a temperature of about 4.
; Ohm's lawOhm's law
[for G. S. Ohm], law stating that the electric current i flowing through a given resistance r is equal to the applied voltage v divided by the resistance, or i=v/r.
; conductionconduction,
transfer of heat or electricity through a substance, resulting from a difference in temperature between different parts of the substance, in the case of heat, or from a difference in electric potential, in the case of electricity.
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## Resistance

The physical property of a material to resist or impede the conduction of electrical current, measured in ohms. High resistance means poor conductivity and vice versa.

## resistance

[ri′zis·təns]
(acoustics)
(electricity)
The opposition that a device or material offers to the flow of direct current, equal to the voltage drop across the element divided by the current through the element. Also known as electrical resistance.
In an alternating-current circuit, the real part of the complex impedance.
(fluid mechanics)
(mechanics)
In damped harmonic motion, the ratio of the frictional resistive force to the speed. Also known as damping coefficient; damping constant; mechanical resistance.

## electrical resistance

The physical property of a device, conductor, element, branch, or system, by virtue of which power is lost as heat when current flows through it; the physical property which an electric conductor exhibits to the flow of current; measured in ohms.

## resistance

1.
a. the opposition to a flow of electric current through a circuit component, medium, or substance. It is the magnitude of the real part of the impedance and is measured in ohms.
b. (as modifier): resistance coupling
2. any force that tends to retard or oppose motion
3. (in psychoanalytical theory) the tendency of a person to prevent the translation of repressed thoughts and ideas from the unconscious to the conscious and esp to resist the analyst's attempt to bring this about
4. Physics the magnitude of the real part of the acoustic or mechanical impedance
References in periodicals archive ?
V[O.sub.2] max, maximum oxygen uptake; SVRI, systemic vascular resistance index; MFI, microvascular flow index of small vessels; PPV, percentage of perfused small vessels; TVD, total vessel density of small vessels; FCD, functional capillary density.
Listening to recorded traffic noise resulted in a significant decrease in stroke volume and cardiac output and increased systemic vascular resistance. Heart rate variability and the general state of the autonomic nervous system remained similar in all periods of the experiment.
Concerns about a possible interaction between aspirin and ACE inhibitors began with a 1992 hemodynamic study, later confirmed by others, showing that coadministration of enalapril and aspirin in 18 patients with severe heart failure attenuated some of the hemodynamic effects of ACE inhibitors on systemic vascular resistance.
In a study of 45 hypertensive heart transplant recipients, researchers at the University of Oslo in Norway found that compared to placebo, omega-3 fatty acids protected patients against significant increases in blood pressure and systemic vascular resistance and worsening of plasma creatinine and the glomerular filtration rate.
SBP: Systolic blood pressure, DBP: Diastolic blood pressure, HR: Heart rate, CO: Cardiac output, SV: Stroke volume, SPR: Systemic peripheral resistance, CI: Cardiac index, SI: Stroke volume index, SVRI: Systemic vascular resistance index
Firstly, immediately after injection, decrease in the systemic vascular resistance and mean arterial pressure predominate.
"'Increased systemic vascular resistance, arterial stiffness, altered endothelial function, increased atherosclerosis, and altered coagulability have been reported to be associated with subclinical hypothyroidism and may accelerate CHD," they noted.
We planned an anaesthetic technique which was likely to be haemodynamically stable and did not need to use any haemodynamically active drugs to deal with systemic vascular resistance (SVR), pulmonary vascular resistance (PVR) or contractility.
In uncorrected or palliated pregnant patients with cyanotic congenital heart disease the usual pregnancy associated fall in systemic vascular resistance and rise in CO exacerbate right to left shunting leading to increased maternal hypoxemia and cyanosis.
Ularitide also produced a dose-related increase in the cardiac index and a reduction in systemic vascular resistance.
INTRODUCTION: Laparoscopic surgeries are routinely performed under general anesthesia & are associated with unique hemodynamic changes in the form of increased systemic vascular resistance, especially due to pneumoperitonium.

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