lecture 2 - respiratory physiology Flashcards
why do we breathe?
cells require energy to function (ATP) which is stored in limited quantities - to generate this we need o2 and it generates co2
what is the conducting zone?
no gas exchange take place
Air in the conduction zone is warmed and moistened
The conducting zone is termed anatomic “dead space”
what is the respiratory zone?
capillaries - site of gas exchange
what is boyles law?
decreasing vol increases collisions and pressure
what is atmospheric pressure?
760mmHg
how does pressure move?
along a pressure gradient
how do we breathe?
inspiration - externa; intercostals and diaphragm contract and the chest wall and lungs expand, expansion of ribs moves sternum upward and outward
what is inspiration?
muscles contract, increase in lung vol, decrease in intrapulmonary pressure, changes in pressure gradient
what is expiration?
muscles relax and recoil, decrease lung vol, increase in intrapulmonary pressure, change in pressure gradient
what happens to air pressure as it flows through the trachea?
its reduced
what is henrys law?
Mass of a gas that dissolves in a fluid at a given temperature varies directly with the pressure of the gas over the liquid
what does the rate of diffusion depend on?
Partial pressure between gas above the fluid and gas in the fluid
Solubility coefficient of gas
Surface area for gas exchange
what is Fick’s law of diffusion?
diffusion constant x area for gas exchange x ((P2-P1)/distance (thickness of barrier)
what is involved in alveolar ventilation?
tidal vol
what reduces alveolar ventilation?
shallow breathing
what is the inspiratory reserve vol?
vol of air brought into the lung after normal inspiration
what is the expiratory reserve vol?
vol of air brought out of the lung after normal expiration
what is forced vital capacity?
max air expired after max inspiration
what is the residual lung vol?
vol in lungs after max expiration
what does dynamic ventilation depend on?
FVC, airflow velocity
what does airflow velocity depend on?
resistance of the respiratory passage to the flow of air, compliance of the chest and lung tissue
what does more compliance of the chest wall and lung tissue mean?
more easily stretched
what does less compliance of the chest wall and lung tissue mean?
less easily stretched
what happens to pulmonary ventilation during exercise?
increase in min ventilation via increases in TV and breath frequency
