resistance

Physiology

(noun)

The resistance which must be overcome by pressure to maintain blood flow throughout the body.

Related Terms

  • diastolic pressure
  • Voltage
  • flow
  • pressure
  • hypotension
  • current
  • vasodilation
  • systolic pressure
  • vasoconstriction
  • voltmeter
  • potential difference
  • voltage

(noun)

Hindrance to the flow of charge.

Related Terms

  • diastolic pressure
  • Voltage
  • flow
  • pressure
  • hypotension
  • current
  • vasodilation
  • systolic pressure
  • vasoconstriction
  • voltmeter
  • potential difference
  • voltage
Physics

(noun)

The opposition to the passage of an electric current through that element.

Related Terms

  • parallel
  • series
Biology

(noun)

the tendency of a system to remain close to its equilibrium state, despite disturbances

Related Terms

  • resilience
  • equilibrium

Examples of resistance in the following topics:

  • Resistance and Resistivity

    • Resistance and resistivity describe the extent to which an object or material impedes the flow of electric current.
    • Conductance and resistance are reciprocals .
    • What determines resistivity?
    • Its resistance to the flow of current is similar to the resistance posed by a pipe to fluid flow.
    • Identify properties of the material that are described by the resistance and resistivity
  • Resistance to French Rule

  • Dependence of Resistance on Temperature

    • Resistivity and resistance depend on temperature with the dependence being linear for small temperature changes and nonlinear for large.
    • The resistivity of all materials depends on temperature.
    • where ρ0 is the original resistivity and α is the temperature coefficient of resistivity.
    • is the temperature dependence of the resistance of an object, where R0 is the original resistance and R is the resistance after a temperature change T.
    • Compare temperature dependence of resistivity and resistance for large and small temperature changes
  • Mechanisms of Resistance

    • Resistance can be mediated by the environment or the microorganism itself .
    • Intrinsic resistance is considered to be a natural and inherited property with high predictability.
    • Once the identity of the organism is known, the aspects of its anti-microbial resistance are also recognized.
    • On the other hand, acquired resistance results from a change in the organism's genetic makeup.
    • Describe the mechanisms bacteria use to develop antimicrobial resistance and the factors that can lead to it
  • Factors Affecting Pulmonary Ventilation: Airway Resistance

    • Airway resistance refers to resistance in the respiratory tract to airflow.
    • Airway resistance can change over time, especially during an asthma attack when the airways constricts causing an increase in airway resistance.
    • Below is the equation for calculating airway resistance (R).
    • Therefore the resistance to air in the bronchi is greater than the resistance to air in the trachea.
    • Laminar flow (a) has orderly layers and low resistance.
  • Cost and Prevention of Resistance

    • Antimicrobial resistance is a major public health and economic burden on patients, affected communities, and healthcare providers.
    • Patients who are infected with bacterial strains resistant to more than one type or class of drugs (multidrug-resistant organisms, MDRO) often have an increased risk of prolonged illness, extended hospital stay, and mortality.
    • Multidrug resistance forces healthcare providers to use antibiotics that are more expensive or more toxic to the patient.
    • Research and development of new drugs effective against resistant bacterial strains also comes at a cost.
    • Antibiotic misuse is a major cause of the staggering healthcare costs for the treatment of resistant bacterial strains.
  • Relative Resistance of Microbes

    • Endospores are considered the most resistant structure of microbes .
    • They are resistant to most agents that would normally kill the vegetative cells from which they formed.
    • Certain bacterial species are more resistant to treatment than others.
    • Gram-negative bacteria have high natural resistance to some antibiotics.
    • Staphylococcus aureus is one of the major resistant pathogens.
  • Resisitors in Series

    • The total resistance in the circuit with resistors connected in series is equal to the sum of the individual resistances.
    • A measure of this limit on charge flow is called resistance.
    • The total resistance in the circuit is equal to the sum of the individual resistances, since the current has to pass through each resistor in sequence through the circuit.
    • This implies that the total resistance in a series is equal to the sum of the individual resistances.
    • Since all of the current must pass through each resistor, it experiences the resistance of each, and resistances in series simply add up.
  • Introduction to Blood Flow, Pressure, and Resistance

    • Resistance to flow must be overcome to push blood through the circulatory system.
    • If resistance increases, either pressure must increase to maintain flow, or flow rate must reduce to maintain pressure.
    • Numerous factors can alter resistance, but the three most important are vessel length, vessel radius, and blood viscosity.
    • With increasing length, increasing viscosity, and decreasing radius, resistance is increased.
    • The resistance offered by peripheral circulation is known as systemic vascular resistance (SVR), while the resistance offered by the vasculature of the lungs is known as pulmonary vascular resistance (PVR).
  • Combination Circuits

    • This is commonly encountered, especially when wire resistances is considered.
    • In that case, wire resistance is in series with other resistances that are in parallel.
    • Essentially, wire resistance is a series with the resistor.
    • It thus increases the total resistance and decreases the current.
    • Each is identified and reduced to an equivalent resistance, and these are further reduced until a single equivalent resistance is reached.
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