Respiratory system Flashcards
As you inhale and expand the rib cage, what happens to the air pressure in the lungs?
Decrease in pressure because more volume, same amount of air. Movement of air is all about pressure difference.
Compliance
How easily lungs can inflate or expand under pressure. Pulmonary infections can reduce lung compliance
Elasticity
the tendency of a structure to return to its initial size after being distended.
High content of elastin
Pulmonary fibrosis
reduces lung compliance
Cigarette smoking reduces the elasticity of the lungs what effect will that have on respiration, as measured with a spirometer
Effect in tidal volume, can inhale, can’t exhale as easily. rapid shallow breathing
What is the benefit of breathin 100% oxygen? What is the Po2 of 100% oxygen?
More transport
Functions of pulmonary system
gas exchange, pH regulation, immune function
Two functional sections of pulmonary system
conducting zone: warmed and humidified, mucus cells and cilliated cells.
ventilatory/respiratory zone
inspiration
diaphragm contracts, increasing volume, external intercostals bring ribcage up and out
Emphysema does what to compliance
increases
Fibrosis does what to compliance
decreases
alveolus SA and number
60-80 m^2 and ~300 million
Type I alveolar cells
play a role in gas exchange between air pockets and blood sheets (sheets like capillaries). Primary function is to exchange CO2 and O2 between airspace and blood
Type II alveolar cells
produce and secrete surfactant, preventing small airways from collapsing
surfactant
lowers the surface tension, preventing small airways from collapsing
Gas exchange between alveolar air and pulmonary capillaries results in
increased oxygen concentration and decreased carbon dioxide concentration in blood leaving lungs
Dalton’s law
total pressure of a gas mixture is equal to the sum of the pressures that each gas in a mixture exerts independently
Henry’s law
When a liquid/gas such as blood and alveolar air are at equilibrium, the amount of gas dissolved in fluid reaches a max value
Henry’s law is dependent on
solubility of gas in fluid, temp of fluid, partial pressure of the gas
partial pressure depends on
humidity in the air
ventilation/perfusion ratio and it’s significance
ratio is the amount of air getting to alveoli and the amount of blood being sent to lungs, determines blood oxygen/CO2 concentration
Ventilation/perfusion mismatch
top of lung= more air than blood
middle= good match (equilibrium)
bottom= more blood than air
Response to decrease ventilation
decreased outflow, reduces pO2 in blood vessels–> vasoconstriction of pulmonary vessels, increasing BP–> decreases blood flow–> blood flow matches airflow
response to increase ventilation
increased airflow–> elevated po2 in blood vessels–> vasodilation of pulmonary vessels, lowering BP, increasing blood flow–> blood flow matches airflow
