Respiratory Physiology Flashcards
What causes lungs elasticity ?
Surface tension.
Elastin and collagen fibers.
Results in elastic recoil that opposes alveolar expansion (compliance)
What is boyles law?
Boyles law states that pressure and volume are inversely related, meaning that when he lung volume increases, lung pressure decreases and vice versa.
What is Dalton’s law ? (Partial pressures)
It refers to the partial presumes entered by a single gas on amicture.
Factors- pressure of the gas mixture. Relative proportion of the gas in the mixture.
What is Darcy’s law of airflow?
Airflow is proportional to the difference in pressure gradient and inversely proportial to resistance flow.
What is ficks law ( rate of gas diffusion) ?
Rate of diffusion of gases directly proportional to -
Partial pressure gradient.
Surface area of membrane.
Gas molecule solubility ( at 37 degrees)
Inversely proportional to :
Membrane thickness
Size of gas molecule
.
What is Henry’s law ( gas concentration in a solution)?
The concentration of a gas molecule dissolved in a fluid is proportional to:
Primal pressure of the gas.
The solubility of the gas in the fluid.
What is hypoxia pulmonary vasoconstriction and why does it occur ?
Pulmonary arterioles vasoconstric when they detect low oxygen, high C02 and low PH, reducing perfusion.
This occurs when an alveolus isn’t receiving airflow and ant participate i gas exchange to maintain the V/Q ratio
What is lung compliance and elasticity?
Lung compliance is how distensibel (capable of being stretched/expanded) the lung and chest wall is.
Lung elasticity is its and the chest walls restiance to being distended and its ability to return to its original shape and size following distension.
Compliance and elastics are inversely related.
What is poiseuilles law of resistance flow ?
Resistance is determined by fluid viscosity tube length and tube radius. Tube radius begins the main and most acutely changeable factors in resistance.
What si secreted by type II alveolar cells ?
Surfactant
What is the structure and function of surfactant?
Surfactant is an amphipathic molecule made of phospholipids and proteins produced by type two Alviola cells which reduces surface tension. Net in wood force of surface water molecules, compressed together due to only lateral and inferior attracting forces making them want to assume smallest size possible.
Surfactant reduces surface tension through hydrophobic end which exerts attraction to force upwards and hydrophilic, and which interacts with water molecules, pulling water molecules up and decreasing the cohesion.
What is the volume of gas in the anatomical dead space?
Around 150 ML
What is the V/Q (ventilation/perfusion ratio)?
The V/Q ratio is a ratio how much air ventilate alveoli and how much blood perfuses Alveolar capillaries four gas exchange over one minute.
A normal V/Q in a healthy lung is around 0.8 to 0.9 as normal alveolar ventilation is around 4L/min and Alveolar perfusion is around 5L/min although this varies between regions of the lungs .
What occurs during quiet inspiration?
The diaphragm contracts (flattens) and external coastal contract ( move chest walls up and out) .
Transient drop in intraplaural pressure (increased pleural volume).
Transpulmonary pressure increases and outward forces, overcome, long elastic recoil.
Lung volume increases (pressures drops).
Pressure gradient drives air into the lungs .
What pathway causes bronchoconstriction ?
Cholinergic (involving acetylcholine) parasympathetic innovation via the vagus nerve causes acetylcholine binding into M3 muscainic receptors triggering bronchoconstriction.
