Respiratory Physiology Flashcards
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
Moderate COPD
Moderate COPD has more resistance when air flow into or out of the lung
time of normal
Normal - inhaltion and exhalation are similar amount of time
time of moderate COPD
Moderate COPD - more time spent on exhaltion and more pressure needed overall
time of serve COPD
Serve - more time furthmoer spent on exhlaton and more pressure on that
What is Buffer Puffer
Buffer Puffer - alveoli destruction , reduces surface area, reduced elasicity
How to overcome elastic and non elastic resistacne
Work = force x distance = pressure x volume
Work of Breathing
Inspiration - energy input required to overcome elastic component and surface tension
Expriation - energy input to overcome airways and tissue resistance
how does panting work
Panting - work harder to overcome surface tension and dynamic compression and overcome upper airways. Tidal volume is going to be less painting breathes are shallower
Deep Breathing
deep breath - bigger tidal volume to more of vital capcity but frequency decreases and elastic recoil of the lung is used mDore and surface tension is dissipated as taking longer to expand the aveoli
Embryonic
Embryonic: establishes basic lung structure as a template for furthergrowth
Pseudoglandualr
Pseudoglandular: establishes the branched network of gas conducting airway
Canalicular
Canalicular : Formation of the blood-gas barrier
Saccular
Saccular : Formation of the respiratory acinus – the zone of gas exchange
Alveolar
Alveolar: Formation of the alveolus and high surface area for gas exchange. 5x increase in surface area for 2x increase in lung volume.
what is irregular dichotomous braching
Irregular DIchotomous branching is the regulated increase in the number of airways at each branch disperses air flow resistance which would otherwise increase with distance into the lung
What does irregualr dichotomous branching allow
Irregular dichotomous branching allows disperal of gas among terminal airways branches mechanical strain dispersed evenly among units
what happens with chloride
A chloride gradient drives fluid movement into the airway lumen giving mechanical support for 3D growth. Chlorine accumulates against its electrochemical gradient
what is fractual
Fractal is a repreated geometric shape repeated at different magnitudes - the repitive shape of airway and blood vessel branches
what is conductive zone
the conductive zone is the dead space within the lung as it does actively participate in gas exchange
what is the respiratory zone
the respiratory zone is wehre the alvolei is being formed around the airway region and gas exchange occurs
What is partial pressure
partial pressure tells you the direction of movement of gas
gas moves from high partial pressure to low partial pressure
partial pressure rules
gas moves down its partial pressure graident
O2 moves from avoleoar to blood
there is a corrections for water vapour
how does gas move in the body
Becomes hydrated then it mixes down tot he avoleoar gas
From their, it diffuses across the4 blood gas barrier into the pulmonary vein into the heart and around the body then makes it way to mitochondria where it is converted to water in the process of oxidative phopshorylation to generate ATP
what is the consequences of airway branching
airway branching has two consequences: increases surface area for gas exchange and dissipates resistance to air flow as airway diameter narrow towards the respiratory zone
Poiseuille law
Poiseuille law is the doubling total airway diameter at each branch generation reduces resistance 16 fold
what is bulk flow of gas into the conductive zone driven by
The bulk flow of gas into the conductive zone is driven bydifference in net pressure caused by expansion andrelaxation of the chest cavity
Gas moves into alveoli
Gas moves into alveoli if : alveolar pressure less than atmospheric
gas moves out to alveoli
gas moves of alveoli if : alveolar pressure greater than atmospheric
the alveolar pressure
the alveolar pressure is the sum of elastic recoil pressure and pleural pressure
how does the lungs move during inspiration
During inspiration the external intercostal muscles between the ribcages pulls the structure of the ribcage upwards and outwards
how does the lung move during expiration
External intercostal muscle - slope oblqieuly between ribs forward and down because the attachment to the lower rib is father forward from the axis of rotation contraction raises the lower rib more than it depresses the upper rib
muscles of inspiratory
muscle of inspiratiry - diaphgram , external intercostals , accessory muscles
