Respiratory Physiology Flashcards
(56 cards)
Gas moves through the airways by
Gas moves through the airways by resistance to gas flow and tuberbulence
Why does reistance arise
Reistance to gas flow in the lungs due to the one trachea the smallest tube has the greatest airway resistance - due to cumulative resistance is lower (Posieuille Law)
factors determining determining
The factors determining resistance : lung volume and branching , bronchiolar smooth muscle tone and density and visoisty of gases
tube raidus does what by muscular contraction
decrease
why tube radius decreased by muscualr contraction
muscular contraction is by parasympathetic activity, ACh neurotransmission, irritants, decreased alveolar PCO2
what happens to tube raidus to cause relaxation
increases
muscular relaxation
muscular relaxation is by sympathetic activity, pulmonary stretch , NAdr and Adr
how astham causes resistance
when an asthma attack occurs hyper reaxtivity of airway smooth muscle contraction which causes bronchial smooth muscle to thicken
what does the graph for resistance and airway generation show
asthma causes the resistance by every airway generation to increase (shift to the right) as convective gas flow in lungs much less efficient
Krough Oyxgen coeffeicent
How gas moves at rest - airways by convention - expands and relaxation allows ventrialtion of the lung
Gas enters the airways and penetrates the region of low resistance it travel and hits the point where oxygen is moving at krough oxygen coefficient (molecular diffusion rate through bulk air) so therefore lose the convention affect at the cross ection and after that oxygen gets through diffusion (due to going its own velocity)
how does gas movement by excerise
During Excerise convention of the lung increases and ventilation is more vigor allow more convert movement - so there is slow molecular movement into the venous respiratory conduction pathway
how does asthma
asthma is moved leftward to molecualr viscoisty so it slow down molecular velocity a lot faster as there is more resistance
how is airway resistance measurement
measurement of airway resistance is done by whole body plethysmography
Inspiration and expiration graph
During inhalation, airway resistance falls as gas flow and lung volume increase
Resistance to gas flow is dissipated due to branching (poisuelles)
Dynamic lowering tethering of aovlei to one another
As airway resistance decline gas flow into the lung increase
what is the mechanical tethering
as the lung expands the increasing tension in alveolar walls pulls conducting airways open
how is the resistance upper airways exhaltion
During exhalation the resistance of the upper airways help to keep airways pressure high to maximise gas movement of the aveoli
what happens with resistance during inhaltion
Inhalation as gas enters the airways resistance of gas movement is being dispatteded by the branch structure
exhalation loop and inhlation loop
Hytersis - largechnage in flow to change in vital capacity
Elastic recoil is putting pressure onto the lung to a point where it ovecomes the upper airway resistance - dynamic compression
After this point gs can move out of the lungs to allow the next inhale
graph for inhalation
During an Inspiration
Negative pressure between intrupural pressure and airway pressure
The greatest pressure difference is in the conducting zone
Pressure difference change decreases at the avoleus
By expanding the chest cavity you reduce intrpural pressure
Pulls airway pressure down below atmospheric pressure so gas begins to enter the airways
The main driving force for gas entering the conductive airways
Due to the gradient
end of inspriation
End inspiration
Short period after inhalation and before exhlation
Intramural pressure remains more negative than airway pressur due to the tahering of the lung to the chest wall
No movement so it remains the same all the way through
Expiartion
Expiration
Lung begins to collapse because of surface tension and elastic recoil
Dynamic compression of the lung
Intrpurla pressure is positive - arises airway pressure of aolvei above atmospheric pressure
Dynamic impression of the avolei that raises airway pressure sufficiently so gas can move out of the airways into the mouth
Airway pressure falls belowintrpural pressure - dynamic pressure avolei across this zone at the point matches the resistance of the conducting airways as it moves out of the branch network of the airways into the trachea
Puffing Expiration
Puffing during expiration
Puff lip breathing doing maintain airway pressure high through conducting zone so do not have the fall that is normal in airway pressure
Maximal resistance at their mouth and using dynamic pressure to go up above intrpural pressure through the airways
Producing a dynamic compression to clear the lung of gas
normal reisistant pressure with air flow into lung
normal has not much chnage iwht inhaltion and exhlation
serve COPD
With serve COPD there is a much greater resistance to air flow during exhalation but inflation looks normal
