chest and wall mechanics Flashcards
what is boyles law?
pressure exerted by a gas in inversely proportional to its volume
whats daltons law
the total pressure of a gas mixture is the sum of the pressures of the individual gases.
whats charles law?
that the volume occupied by a gas is directly related to the absolute temperature (v α T)
Whats Henry’s law
the amount of gas dissolved in a liquid is determined by the pressure of the gas and it’s solubility in the liquid.
what is the lower resp system enclosed in
the thorax bounded by the ribs, spine and diaphragm
what is the thorax covered by?
pleural membranes
what does the visceral pleural membrane coat?
outer surface of the lungs
what does the parietal pleural membrane coat?
inner suface of the ribs
what is asthma
over- reactive constriction of bronchial smooth muscle increasses resistance, expiration difficult
which pressure is always negative
intra pleural pressure
which pressure is always positive
transpulmonary pressure
which pressure can be negative or positive
intra thoracic pressure
what are the two types of pleural cavities
parietal and visceral
which pleural cavity is most sensitive to pain
parietal
whats important about the relationship between the lungs and the ribcage?
the fluid between them means they resist seperation and always moves together
what action do lungs want to do?
contract and recoil inwards
what action does the ribcage want to do?
extend and recoil outwards
why would there be negative pressure in the lungs/ribcage?
lung recoils inwards and ribs recoil outwards
why is transpulmonary pressure always positive?
because the intra-pleural pressure is always negative
what is used for inspiration?
external intercostals muscles and the diaphragm
what is used for expiration?
internal intercostal and abdominal muscles
what are the muscles used for ventilation?
inspiration- diaphargm, external intercostals, sternocleidomastoids and scalenes.
expiration- internal intercostals and abdominals
is diaphragm relaxed or contracting at inspiration?
contracting
