CHAPTER 3

VENTILATORY DYNAMICS

GENERAL OBSERVATIONS IN A CONTINUOUS SERIES OF RESPIRATORY PULSES

 

5. Series of three cycles of transmitted impulses, as detected in the pleural space "Respiratory Pulse", and simultaneous tidal volume intake. Main inflexions correspond to dynamics for inspiration. Small cycles of inflexions correspond to the 1,obular-alveolo-capillary dynamics for gas interchange with the blood.

 

Fig. 5 Shows the pulses of a series of three respiratory cycles framed between the starting point of the fourth cycle at the right and the end of another cycle at the left. The major upward inflexions correspond to the respective inspiratory impulses and the following downward inflexion to pulmonary relaxation and tone regulation. The shallow part, on a slight incline, completes the recovery of the tone at the end of which a new inspiratory inflexion is produced.

A line a-b has been drawn following the axis of the ascending slope. Parallels to this line have also been traced through analogous points of the other inflexions. The area occupied by the inspiratory inflexions has then been closed by drawing a plotted horizontal tangent to the lower part of the graph, now being enclosed in the triangular areas, which circumscribe the graphs of impulses, generated during the pulmonary inspiratory phase. These triangles are equal and the circumscribed graphs are similar; therefore, the phenomena that determine them are similar in intensity, duration and frequency.

If the graphs of the whole cyclic waves of pressure are now observed, it is possible to distinguish small inflexions, which are repeated periodically and can be identified by their characteristics. These small inflexions correspond to the lobular-alveolo-capillary cycles.

Finally, a line e-f has been drawn tangent to the lowest part of the shallow segment of the first pulse, as well as a perpendicular from this line to the vertex of the graph and parallels have also been traced to the corresponding points of the other cycle.

 

RESULTS

1. Base level = +8 mm. Hg.

2. Amplitude of the inspiratory impulse (average) = + 12 mm. Hg.

3. Slant of the shallow segment of the graph: +1.2 mm. Hg. (after 3.5 sec.).

4. Duration of the inspiratory impulses: (constant) .

5. Duration of the descending slope and the shallow segment of the graph: variable.

6. Duration of the whole cycle: variable.

 

CONCLUSIONS

1. The inspiratory inflexion has a constant duration, which is similar in all cycles.

2. The starting and ending points of the inspiratory inflexion reach the same level, which means that the Resultant of the dynamic conditions for each inspiratory impulse detected at the pleural space, is similar throughout the series of cycles.

3. The small inflexions or: "Lobular pulses" present a small cyclic difference in duration between one another, which is the subject of analysis in chapter 2.

4. The descending slope and shallow segment of the graph, corresponding to bronchi-relaxation followed by pulmonary expansion and elastic retraction has a duration, which varies within narrow limits for each ventilatory cycle, which is relative to the general dynamic conditions.

5. The retracting period of the pulmonary structure (shown by the tangent e-f and its parallels) indicates that the pressure detected during the recovery of he pulmonary tone increases uniformly up to 1.2 mm. Hg., from the lowest point in the base level, which is possibly the determinant in the changes of the alveoli-capillary cycles as organic dynamic adaptation. This is extensively analysed in chapter 2.

6. This retracting period (tangent e-f) maintains its characteristic during about 3.5 sec. (average period of cycles 1 and 2), throughout the experiment. The third respiratory cycle of the graph is longer at the expense of its retracting phase, which has given place to an extra lobular cycle. The detected pressure after 3.5 sec. has dropped below the lowest point of the base level which allows us to conclude that the Resultant of the forces in the pleural space, is lower than that reached during the previous cycles (at this point in the cycle referred to).

Furthermore, such a drop in tension would be attributed to the extra consumption of the stored air during this cycle (residual volume) i.e., The level of the residual volume reached during cycles 1 and 2, has decreased for this cycle, with the dynamic consequences we have observed.

 

ANALYSIS OF THE INSPIRATORY PHASE OF THE RESPIRATORY CYCLE

All the characteristic inflexions of the lobular pulse are now possible to identify, as well as parallel consequences of their effects in the intra-pleural pressure wave which translates changes of capacity in this space, as a result of the pulmonary structure retraction-expansion. These dynamics enable the lobular cycles to perform.

We also know how the pulmonary state of tension throughout the ventilatory cycle influences the alveoli-capillary cycles that take place during each respiratory cycle.

We shall now explain how the inspiratory retraction-expansion of the lung structure effects the entire respiratory system and how he pulmothorax co-ordination responds to the new conditions.

 

CORRELATION BETWEEN THE RESPIRATORY PULSE AND THE INTRA PLEURAL PRESSURE

The Inspiratory Pulse graph is in the shape of a steep hill and can be compared to the slope of the first half of a lobular cycle, the only difference being the great amplitude of the former and the pressure of small inflexions in its contour which correspond to the deformed lobular cycles that take place simultaneously. The deformation makes it difficult to identify these cycles. Therefore, the pleural pressure wave helps to clarify the events; pleural presume wave helps to clarify the events; consequently, we will start our study by analysing the latter curve.

INTRA-PLEURAL PRESSURE GRAPH. The inspiratory dynamic effects reflected in the intra-pleural pressure graph appear as a trough in the base level line. This depression indicates an increase in pleural capacity, which is foreign to the lobular cycle dynamics, as can be concluded from the fact that the correspondent waves of the lobular cycles included in the contour of that depression are identifiable. They take on the appearance of the parts of a metallic bridge which has collapsed, their parts being identifiable because of their location and because their general shape and length remain similar among the deformations determined by the stress conditions to which they were subjected.

 

6. Fragment of fig. 5 (corresponding to inspiration), for a better differentiation of the effects produced by inspiratory dynamics, from those of coincident lobular-alveolo-capillary dynamics. The plotted area in the Respiratory Pulse graph corresponds to variations in pressure of the air displaced to the pulmonary periphery. The plotted area in the intra-pleural pressure graph corresponds to simultaneous effects in the pressure the intra-pleural vapour, which translates the changes in pleural capacity. Parallel effects in the abdominal aortic pulses are due to pressure variations in the abdominal cavity. The clear zone around the plotted area shows similar effects produced by the dynamics of the coincident lobular-alveolo-capillary cycles.

 

For the identification of the these waves, we have chosen the following:

1. The aortic pulses, each one of which refers to the corresponding alveolo-capillary pulse slope, or first part of the second half of the lobular cycles.

2. The upper points of the intra-pleural pressure graph which touch the base level line, marked with arrows 1, 2 and 3, in fig. 6.

3. The deepest points of the same graph which correspond to the central part of each lobular cycle (arrows 4 and 5).

All the similar points in the graph are identifiable with the help of these references, which allow us to limit the corresponding area to each lobular cycle. The plotted area corresponds to the effects of the inspiratory dynamics in the pleural space, while the white area corresponds to those of lobular cycle dynamics.

RESPIRATORY PULSE. The vertical projection of the above identified referential points along the Respiratory Pulse wave, permit the identification of the inflexions that would correspond to lobular and alveolo-capillary actions, due to their chronological correspondence. A similar method to that mentioned above enables us to delimit the area, which would correspond to the inspiratory dynamic effects as opposed to those that correspond to the lobular-alveolo-capillary dynamics.

The contour of the inspiratory impulses "net" graph (total area less that corresponding to the effects of lobular impulses) has a similar, but inverted shape to that of the "net" area of the intra-pleural Pressure graph. This is a consequence of the changes of capacity of the pleural space in converse proportion. Therefore, it is possible to conclude:

 

CONCLUSIONS

1. The changes in capacity in the pleural space during inspiration are correlative to pulmonary ventilatory dynamics, whose transmitted impulses, as Resultants, generate the inspiratory impulse.

2. The inspiratory pulse, as detected in the pleural space, is the Resultant of the effects of the airway constriction, the actions, reactions and reflexes that it determines in the thorax walls (firstly the diaphragm and then the costal wall), as well as the impulses generated by displacement of the intra-pulmonary mass of air under those conditions.

3. All these actions, reactions and reflexes determine co-ordinated displacements of the thorax walls for pulmonary expansion, in which expansion the retracting elastic forces of the pulmonary structure are always, present. Therefore:

4. The intra-pleural sub-atmospheric pressure changes are correlative to the capacity-changes of the pleural space.

5. The pleural capacity-changes are determines by the pulmonary primary retraction, followed by the diaphragm and costal wall, within the limits imposed by pleural adhesion, as analysed in chapter # 4.

6. The relation between the intensity of the dynamic phenomena at the pulmonary respiratory zone (lobular zone) and their consequent broadening of the pleural space is minimal (about one to one), remaining steady throughout the whole ventilatory cycle as in our study, while the quotient of the intensity of the inspiratory impulses and their mechanical consequences, broadening the pleural space, is very great: 10 to 1.

7. The lobular-alveolo-capillary cycles included in one ventilatory cycle remain steady, despite the strong dynamic changes, which take place during the entire ventilatory cycle.

8. The essence of the co-ordinated dynamics on both sides of the pleural space, with cardiac rhythm, is to enable alveolo-capillary expansion, which is achieved by the actively co-ordinated constriction-relaxation of the pulmonary structure and, consequently:

9. The potential elastic stretching-retracting of the pleural medium of adhesion is the balanced resistance that limits the increase and the decrease in pleural capacity.

10. Similar to the mechanisms, which determine the broadening of the pleural space during the lobular alveolo-capillary cycle, must be those that cause the major increase in the same space during the first part of inspiration, although they take place at a different structural level; i.e., ventilatory level.

 

ANALYSIS OF THE INSPIRATORY IMPULSES

METHODS

RESPIRATORY PULSE. Figs. 6 and 7. A plotted tangent at its lowest point has been drawn, with the object of showing the moment at which the correspondent impulses to the physiological phenomena of inspiration begins to be detected. This very moment has been determines by the intersection of the above mentioned tangent and the plotted vertical 1.

INTRA-PLEURAL PRESSURE. Figs. 6 and 7. A plotted tangent has also been drawn at its upper point, with a similar purpose to the one referred to above, i.e., to show the moment at which the intra-pleural sub-atmospheric pressure starts to increase in relation to the inspiratory impulses. This point coincides with the projection of vertical 1.

TIDAL VOLUME. We have traced a horizontal line to show the moment at which the air volume-mass begins to penetrate the upper airways. At this point we have traced vertical 2, which we have projected downwards to show the correspondent points in the other graphs. The tidal volume continues to penetrate up to the moment shown by the intersection of its graph and the tangent at its upper point. At this stage we have drawn vertical 4, which we have also projected downwards.

At the summit of the graph of the inspiratory impulses, we have drawn vertical 3, to show both the moments at which the impulses reach their highest intensity, and the corresponding points in the other graphs.

Finally, vertical 5 shows the end of the inspiratory impulses downward slope and their correlative effects as they are detected in other graphs.

 

PERIOD 1 - 2

Characterised by a sudden upward displacement of the Respiratory Pulse curve which from the base level, at the end of the former cycle, increases up to 3.8 mm Hg. during 0.25 sec.

 

7. Magnified fragment of fig. 4 (corresponding to inspiration), for analysis of the simultaneous events, which take place during inspiration.

 

This event is simultaneous to the decrement in the intra-pleural sub-atmospheric pressure, which, from its base level, drops 1.4 mm, Hg. during the same period. This translates a proportional increase of the pleural capacity. This change of capacity also includes its simultaneous increment determines by the dynamics of the lobular cycle that takes place at the same time.

It is worth noting that the atmospheric air has not begun to enter the lungs at the end of this period, which means that the generated impulses can only be produced by the displacement of the retained volume-mass of air (residual volume), which is in accordance with our interpretation.

If the estimate of the sub-atmospheric pressure decrease at the end of this period, determines by the dynamic effect of the coincident lobular cycle (which is -0.7 mm Hg.), is rested from the total-decrease, which is 1.4 mm Hg., the result would be 1.4 - 0.7 = 0.7, which means that each one of the dynamic phenomena determines a similar fall in the intra-pleural sub-atmospheric pressure. These two effects have to be produced by specific actions and reactions, which is what we are trying to demonstrate.

 

INTERPRETATION

The contraction of the tracheo-bronchial smooth muscles determines a decrease in diameter and length of the airways with the following consequences:

1. Pressurisation of the container air mass (residual volume) according to the Boyle-Mariotte Principle.

2. Ejection of the same air mass toward the pulmonary periphery where it acquires the pressure of about 3.8-mm Hg., at this very moment. The components of this Resultant of 3.8 mm Hg. have a direction and sense towards the centre-lobular bronchiole as deduced from the general division and distribution of the intra-pulmonary airways.

3. Traction of the visceral pleura by shortening of the pulmonary structure. The object of this is to pull the visceral pleura, which in turn pull the thorax wall, this latter by means of pleural adhesion. Consequently, the pleural diameter increases an-d the diaphragm is suddenly traction, evoking the reflex to start diaphragmatic contraction and the events, which mark the beginning of the next period.

 

PERIOD 2 - 3

Characterised by a great increment of the inspiratory impulses, which reach about +l0 mm. Hg. (less the corresponding impulse of the lobular dynamics at this moment). This increase is slower than the one produced during the first period, as deduced from the new inclination acquired by the general tendency of the pulse outline (a-b, c-d).

The intra-pleural sub-atmospheric pressure shows very little decrease if we compare it to that of the previous period: i.e. there is no correlation between the effects of the two kinds of dynamic actions simultaneously detected in the pleural cavity (airways traction and air mass ejection).

It is important to note that the beginning of this period is also the starting point where the atmospheric air begins to enter the lungs, as can be observed in the simultaneous graph of the tidal volume intake.

 

INTERPRETATION

These facts merit attention in their analytical implications as well as in their synthesis by the dynamics of the respiratory apparatus to produce a programmed result.

The change in the respiratory pulse contour, which becomes less steep, although a new volume mass of air is penetrating from the exterior, leads us to think that the Result-ants at each moment are inferior to those expected, in relation to the effects observed in the first phase; therefore, a new working factor must have entered into action to produce an increase in pulmo-thorax capacity. In fact, this new factor is the contraction of the diaphragm in response to pulmonary demand to open ways for the expansion of the formerly pressurised volume-mass of air toward the potential abdominal space; therefore, thorax capacity increases in the axial sense.

Pulmonary expansion, relative to the cone shape of the pulmo-thorax -and to classical conception, could increase the distance between the pleural surfaces, although this does not happen as we have shown. This is possible due to the simultaneous traction of the costal wall by the diaphragm, since intercostal muscles are now relaxed. During this period the diameter of the thorax decreases, as demonstrated in another chapter.

Another important observation is that the intensity of the inspiratory impulses at the very moment at which contraction of the diaphragm begins (3.8 mm Hg.), corresponds to physiological tension needed at the pulmo-diaphragmatic level, i.e., correspond to the threshold of stimulation for the mechano-receptors to evoke the contraction of the central diaphragm. This fact is proof of the primary activity of the lungs which, according to this theory, is manifested as a retracting action followed by the secondary reflex contraction of the diaphragm to facilitate intra-pulmonary air expansion and generate pulses toward the abdomen.

 

PERIOD 3 - 4

This period corresponds to the sudden fall in Inspiratory impulses, while the tidal volume continues to penetrate, reaching base level (in this cyclic pattern)

The intra-pleural sub-atmospheric pressure returns to its base level in a parallel manner.

The return of both pressure curves: inspiratory impulses and sub-atmospheric intra-pleural pressure, to their respective base levels, signifies that the pulmonary structure has achieved maximum muscular relaxation; hence, the intra-pulmonary air-mass has achieved maximum physiological expansion at this moment of the ventilatory cycle, which also means that there is a minimum of physiological tension in the ventilatory structure. From here on the pulmonary airways have to balance their tone to permit a steady state of dynamic conditions and air supply to the lobuli and, henceforth, to the alveoli-capillary units. The cyclic dynamic effects detestable in the pleural space are now those of the lobular cycles and, the steady increase in base line pressure.

 

INTERPRETATION

The apparently paradoxical facts that characterise this period are clarified when it is remembered that any physiological muscular contraction is followed by a controlled relaxing period, hence, the bronchial constriction that starts inspiration is followed by relaxation, therefore the formerly pressurised intra-pulmonary gas then expands; consequently, the respiratory pulse wave drops.

If we add to the above that, the diaphragm starts its active reflex contraction, determining flattening of its dome, shortly after bronchoconstriction and before relaxation, it will be understood that the expansion of the lungs will follow the direction where least resistance is offered, i.e., towards the abdomen, and also that the generated air current will create suction of air from the upper part of the air-column and then from the atmosphere; consequently, the atmospheric air enters the lungs to complete the tidal volume-mass, which is relative to the primary bronchi-constriction.

The final increase in sub-atmospheric intrapleural pressure, which translates a parallel decrease in pleural capacity and diameter, is explained by the joint action of the radial pulmonary expansion and the retraction of the relaxed costal wall, helped by the contraction of the diaphragm.

 

PERIOD 4 - 5

This period is circumscribed between the end of the penetration of the tidal volume-mass into the lungs and the lower level of the inspiratory impulses, due to post-inspiratory bronchi-relaxation, both relative to the Vagus action potential that evokes the primary inspiratory reflex.

 

INTERPRETATION

This is the period of maximal bronchial relaxation, which also coincides with the maximal -diaphragm reflex contraction. The latter, when flattening its dome decreases the resistance to the intra-pulmonary air expansion (previously pressurised).

Bronchus relaxation is followed by periodical recuperation of its tone, to guarantee the steady pressure of the remaining air mass during the costal retraction. This very moment is the end of inspiration as a dynamic function concerned with the penetration of the tidal volume-mass into the lungs.

The traction of the peripheral portion of the diaphragm (innervated by the four or five last intercostal nerves) by its central portion, would evoke the intercostal reflex for costal expansion (which 1 call the "costo-diaphragmatic reflex") as well as the tone increase of the abdominal muscles innervated by the same intercostal nerves.

The bronchus relaxation is followed by its tone periodical recuperation, to guarantee the steady pressure of the remaining air mass along the respiratory cycle, step by step as each fraction of air mass is used by each alveoli-capillary cycle. These actions also lead the lungs to their dynamic conditions at the beginning of the cycle, to start a new inspiration.

 

COMPARATIVE STUDY OF THE RESPIRATORY PULSE AND THE PNEUMOGRAM

The results of the actions and reactions, which are produced during one pulmo-thoracic respiratory cycle, as detected in the pleural space, are now known. We also know the trajectory followed y the pulmo-diaphragmatic expansion in an axial direction. Therefore, we are able to interpret the relation of the above to costal retraction-expansion, attributing to this latter its role in respiratory mechanics.

Costal retraction-expansion is shown by the curve known as the pneumogram, fig. 8.

 

METHOD

A vertical has been drawn along the vertex of the pneumogram, Nš 1. A second vertical has been traced along the cusp of the respiratory pulse graph, Nš 2, and a third one, along the lowest point of the neumogram, Nš 3. The cyclic incursion of the costal wall has now been related to the chronological facts represented in the Respiratory Pulse, which has to do with the generation and progress of costal displacements.

OBSERVATIONS. 1. The descending slope of the pneumogram starts in coincidence with the beginning of the inspiratory impulses (vertical 1) and continues its descent while the inspiratory impulses increase. 2 When the inspiratory pulse reaches its highest level (vertical 2) the costal retraction has only reached half its descent. Later on, (arrow 3) begins the ascending slope, which signifies costal expansion.

 

8. Correlation between Respiratory Pulse graphs and the pneumogram. a. Pulmo-costal Respiratory Pulse graph. b. Pulmo-diaphragmatic Respiratory Pulse graph. c. Pneumogram. Arrow 1 shows the transitional point between two Respiratory Cycles. Inspiration corresponds to descending slope of pneumogram. Period 1-2 corresponds to broncho-constriction. Period 2-3 corresponds to broncho-relaxation and pulmonary axial expansion. Arrow 3 shows initiation of costal expansion, which coincides with elastic pulmonary retraction and diaphragm relaxation.

 

INTERPRETATION

The fact that the inspiratory impulses initiate their generation in coincidence with the beginning of the descending slope of the pneumogram (starting point of costal retraction) has its most obvious explanation in the fact that the contracting action of the respiratory tree smooth muscles determines broncho-constriction. This occurs together with a sudden retraction of the pulmonary structure, followed by the costal wall, which is retracted.

Simultaneously with the intercostal muscles relaxation, a "change of guard" takes place: The reflex to start diaphragmatic contraction is evoked to create space for the axial pulmonary expansion, counter balanced by elastic resistance of the costal wall, which is retracted.

Once the action potential of the Vagus terminates, costal retraction completes half its displacement. From now on, its retraction will be completes by traction exerted by the diaphragmatic "chord" from the periphery of its costal "arch". When this traction reaches its maximum physiological limit, sensitivity threshold of intercos- tal nerves is reached at the periphery of the diaphragm, evoking the intercostal reflex (costo-diaphragmatic reflex). Henceforth, the costal wall will start its active role to widen the base of the thorax. Meanwhile, the -diaphragm relaxes and the lungs retract using the potential energy accumulated during the last part of their axial expansion.

In view of the relaxed condition of the phrenic-diaphragm, as well as the stretching achieved by the pulmonary structure during abdominal expansion, the lungs. initiate axial elastic retraction, passively followed by the diaphragm. At this point the costal wall slows down the pulmo-diaphragmatic retraction and begins to expand outwards. A zone of lower resistance is now created at the pulmonary periphery, due to the actions of two Resultant forces with opposite senses; henceforth, the remaining intra-pulmonary gas expands against lower resistance.

When axial retraction of the lungs reaches its maximum point for this cycle, the costal wall has also reached maximum expansion, both facts coincide with exhaustion of a volume-mass of air similar to that inspired during the same cycle. The mechanical conditions are given at this very moment for the evocation of a new respiratory reflex in order to start a new ventilatory cycle.

 

CONCLUSIONS

Inspiration is a complex physical biological phenomenon performed by the airways and lungs as a whole (as the target organ) in integration with the thorax walls, under pulmonary command and the co-ordination of the autonomic central nervous system.

The objectives of inspiration involve the following.

1.To displace the intra-pulmonary air-mass (named by the author initial volume-mass, in analogy to the first respiratory cycle after delivery; towards the pulmonary periphery, for fractional or "residual volume" in the classical conception) use by the alveoli-capillary cycles comprised in the same ventilatory cycle.

2. To pull the diaphragm for stimulation of the nerve ends, in order to evoke the diaphragmatic reflex contraction.

3. The subsequent bronchi-relaxation and pulmonary expansion which simultaneously generates suction of a new volume-mass of air from the atmosphere, to replace the previously displaced volume-mass.

4. To store the potential energy generated by bronchi-constriction, which makes the above mentioned actions possible.

5. Diaphragm contraction followed by bronchi-relaxation, eliciting intra-pulmonary gas and lung expansion, towards the potential abdominal space.

6. To offer a volume-mass of air at the lobular zone, to be used for gas exchange with the blood.

7. To propagate the generated impulses to the surrounding visceral areas, as a wave of pressure, which guarantees the modulated circulation of organic fluids.

8. The diameter increase of the pleural space, which occurs during the first phase of inspiration, when bronchi-constriction with pulmonary retraction is achieved.

9. Inspiratory bronchi-constriction determines the maximum reduction of pulmonary volume and thoracic capacity, causing the maximum traction of the diaphragm and costal walls, for the cycle beginning; increasing the pressure of contained gases at the same time that they are displaced towards the periphery.

10. The subsequent bronchi-relaxation and pulmonary expansion aided by the diaphragmatic reflex contraction, generates suction in the upper airways, which determines the penetration of the tidal volume.

11. The thorax walls, as exterior support of the lungs, respond by reflex to pulmonary dynamics, by means of the co-ordinated contraction of the muscles innervated by the five or six last intercostals, leading to an alternating increase in the thoracic diameters, according to an organic programme of wide ranging consequences.

12. The maximum expansion of the costal wall and pulmonary elastic retraction at the end of the cycle facilitates stretching of the pulmonary structure, an important factor for the generation of the stimuli that evoke the primary inspiratory reflex for the next ventilatory cycle.

13. Respiration is achieved by means of the following fundamental mechanisms, in chronological order:

1.The contraction of the muscles of the airways up to the vicinity of the lobuli (ventilatory zone).

2. Active retraction of the pulmonary structure.

3. Traction of the diaphragm by the lungs.

4. Reflex contraction of the diaphragm, in response to nerve-end stimulation by the previous traction.

5. Steady relaxation of the airways (ventilatory zone) followed by pulmonary expansion, while the reflex contraction of the diaphragm and the intercostal relaxation are in progress.

6. Diaphragm relaxation followed by intercostal reflex contraction and costal wall expansion.

14.Exhaustion of an air-mass equivalent to that inspired, as well as that of the stored potential energy, coincides with maximum pulmonary elastic retraction and maximum costal expansion.

15. The contraction of the respiratory tree smooth muscle leads to:

1. A decrease in the diameters of the airways.

2. Retraction of the airways and consequently that of the elastic pulmonary structure, and the simultaneous pulling of the diaphragm and costal wall, mediated by pleural adhesion.

3. The maximal decreases in airway capacity, and of the axial diameter of the thorax. At this point, the reflex contraction of the diaphragm is evoked.

4. The primary inspiratory bronchi-constriction determines the size of the potential pulmo-thoracic expansion, which starts at this precise moment.

5.The displacement of the intra-pulmonary air mass, "residual volume" ("initial volume" in the New Theory), towards the pulmonary periphery, where it is stored at high physiological pressure.

16.Bronchial relaxation leads to:

1.Relaxation of the elastic structures, allowing them to be distended by expansion of the air previously displaced at high physiological pressure, This is facilitated by the contraction of the diaphragm.

2.The expansion of the previously displaced air through structural expansion.

3.The total intake of the tidal volume.

17. The contraction of the diaphragm leads to:

1.Active contribution for the expansion of the previously pressurised intra-pulmonary air and the axial displacement of the lungs towards the abdominal potential space, producing maximum physiological distension of the pulmonary structure.

2.Completion of costal retraction, decreasing the costal diameters and directing the pulmonary expansive force in the axial sense, up to the moment at which the intercostal reflex is evoked to initiate active expansion of the costal wall.

18. Relaxation of the diaphragm elicits:

1. Elastic pulmonary retraction.

2. Costal wall expansion.

19. Active costal expansion leads to:

1.Diversion of the elastic pulmonary retraction in a radial sense, widening the mediastinum.

2.An increase in the antero-posterior diameter of the thorax to favour the flow of an increased mass of blood to the auricles.

3.A contribution to the programmed return of the component parts of the pulmo-thorax unit to the dynamic conditions at the beginning of the cycle.

20.Ventilatory dynamics, under the leadership of the active axial pulmonary retraction-expansion, involves the potential abdominal capacity as well as its content in its own dynamics for integrated cyclic dynamics of the trunk and even more, of the whole organism.

21.Respiratory dynamics correlate to cardiac dynamics and both correlates to the total organic dynamics to supply the needs of the cells. These dynamics also concern the dynamic integration of the living organism as a whole in the Universal Dynamics, as reflected in the atmosphere of the environment to which it is adapted.

22.The organism, from the dynamic point of view, works as an Organic-Dynamic-System integrated to the world, to generate the phenomena of life.

23.The atmosphere and the respiratory apparatus are two chambers of a closed circuit for respiratory dynamics.

 


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