Pulmonary Ventilation Flashcards
Pulmonary Ventilation
AKA ventilation
Is the process of breathing ( a regular cycle of inspiration and experation)
Inspiration= inhalation
Expiration= Exhalation
What are the ways the lungs Expand and Contract?
2 ways:
1. enlargement in depth due to raising and lowering of diaphram
- enlargement in width is done by raising and lowering the ribcage
Motions of the Diaphram
Contracting the Diaphragm pulls it downward (inhalation)
Relaxing the diapragm allows it to return (relaxation)
What is the difference between external intercostals VS internal intercostals?
External intercostals contract the rib cage raising the muscles–> inhalation ALONG with anterior scalene, serratus anterior, SCM
Internal intercostals Contracting the ribcage lowering the muscles –> exhalation ALONG with rectus abdominus
Restful Breathing is Predominantly _______
diaphragmatic
Vigorous breathing is substantially ______
rib cage based
All of the muscles of ventilation serve to change the shape of the chest and therefore change ________
the pressure of the lungs
Plural cavity (fluid) is under what kind of pressure?
negative pressure
Negative intrapleural pressure is thought to be due to
- Low blood pressure in pulmonary circulation plus evaporative force in alveoli
- tension created by elastic recoiling lungs coupled with elastic expanding chest
Forces acting on the lungs
elastic
Elastic recoil due to elastin in all interalveolar septa
elastic expansion of chest from ribs and cartilage
Forces acting on lungs cont
Collapsing tendency of alveoli due to presence of water on walls
counteracting effect of “surfactin” from great alveloar cells (type 2 pnemocytes), lessening H2O effects
Forces acting on the lungs (expansion)
expansion of lungs due to negative intrapleural pressure
Changing the intrapleural pressure (size of thorax) does what
changes the lungs accordingly
all approaches require a consideration of pressure and time
changing volume due to changing pressure previously called?
compliance, compliance behavior of lungs is unusual
(Compliance graph)
Inhalation
in an ideal system, inhalation compliance would rise along the dashed line
there are 3 types of work that must be done
respiratory work
can be calculated by considering the area with a compliance graph, in the respiratory system force=pressure and distance= volume
WORK=force x distance
Tissue work
variable depending on the type of breathing, more tissue work would be required when breathing shifts from diaphragmatic to ribcage based ventilation
Airway work
is just like “R” in the hemodynamics formula . Just like in blood flow, the prime determinant is r^4. the significance that obstructed airways or broncioconstricted ones can create labored breathing by greatly increasing the resistance to the flow of air
what determines the total work of inspiration
compliance, tissue resistance, and airway work
When collective work is done what happens?
its stored by the elasticity of the lungs this stored work is avalible for exhalation
exhalation
largely a matter of capturing the stored energy of inspiration
tissue resistance and airway work will consume some of the stored compliance work or energy
Deducting the tissue and airway work of exhalation the remaining work is totally ?
free of work expiration
when stored compliance work drops out (what is spent and reused) and the tissue and airway work is deducted, then combining the work of entire breathing cycle is known as the
work of breathing
Work of breathing percentage
3% of energy spent
Proportion of work spent on breathing does not exceed what %
5%
What increases the work of breathing
airway restrictions, and tissue scaring
Ventilation studied by measuring lung volume and volume changes over time in field is called
spirometry
Tidal volume
regular amount of air ventilated per breath 500ml
inspiratory reserve volume
amount of air that can be inhaled after tidal volume
3000ml
expiratory volume
amount of air that can be exhaled after tidal volume
1000ml
vital capacity
expiratory reserve + tidal volume+ inspiratory reserve 4500ml males 3700ml females
residual volume
amount of air still in lungs after complete exhalation
1000ml
total lung capacity
vital capacity + residual volume
5500ml
Wind knocked out!
due to abnormally large expiratory reserve being expelled which creates neurological drive on the repiratory control centers. possibly due to an extraordinary stretch
