COMPARATIVE ANALYSIS OF THE PULMONARY AND EXTRA PULMONARY AIR-CIRCULATION WITH THE CARDIAC AND BLOOD VESSELS CIRCULATION
A Model for the Twenty-first Century.
New advances in scientific knowledge about Pulmonary Respiration, of which I am the Author, led me to create a new mechanical functional model of the Respiratory Apparatus; to ease both the exposition and understanding of the new ideas, which contrast traditional prevailing beliefs
In the praxis, explanation of the new model could not avoid the transitional use of references with traditional parameters in order to ease its understanding, but also creating the need of a posterior clarification of the differences and consequent rectification.
Respiration is a global function of the living being concerned with cells metabolism, its objective being the exchange of gases relative to that process both, at the cells capillary level or Tissue Respiration and at the level of the alveolar-capillary units or Pulmonary respiration, leading to renovation of gases concerned with the first named exchange.
I have devoted this study to the Organo-Physical Mechanics leading to gas exchange at the alveolar-capillary units or Pulmonary Respiration. This Mechanics, contrary to expectation, is very complex and a great part of it has remained veiled by the shadow of the expiring traditional theory.
The new scientific theory, whose study and reasoned discussion I propose, has been tested during a series of experiments carried out during over twenty years.
This Theory is framed into the following conceptual scheme:
Lung, as the specific viscera of the Respiratory Apparatus, simultaneously performs two different mechanics conveying to the same final objective: one which is concerned with air renovation from the Atmosphere and the other with gas exchange with the blood, both complementing Pulmonary Respiration.
The Lung or ensemble of the pulmonary lobes is an active organ, leader of the whole Respiratory Mechanics, under Vagus-Sympathetic command. Lung is to Pulmonary Respiration what Heart and blood vessels are to Tissue's Respiration.
Lung on one side and Heart-blood vessels on the other, can be independently defined as complex systems of pumps for ejection-reception and circulation of their specific fluids: air or blood.
Similarly, as total blood flows from the left ventricle to the left auricle, passing throughout the tissues capillaries, on one side and the alveolar capillaries on the other side, air flows from the Atmosphere towards the alveoli, in one sense, and from the alveoli towards the Atmosphere in a converse sense.
The following observations focus the main differences and similarities between the two complex circuits:
1. Each pulmonary Lobe is in itself a functional circuit of three steps, two senses and two complementary rhythms, functional circuit for an air mass stream, loaded with 21% of Oxygen on one sense, and another mass loaded with Carbon dioxide on the converse sense. These gases go for and come from the exchange with the blood at their own alveolar-capillary units, during the cycles comprised into a major cycle for air renovation.
2.The used mass of air, coming from the alveoli, must be renewed with a pre-adapted air mass supplied by the corresponding right or left main bronchus.
3. The Lung's circulatory System of air carry out the gas exchange by fractions, at the lobular-alveolar- capillary units of each lobe.
4. A fraction of the circulating blood flows throughout the tissue's capillaries, and another similar fraction simultaneously flows throughout the alveolar capillaries, while a greater volume circulates into the vessels in between, before arriving at their destination. Therefore, this functional design guarantees a constant filling of the whole vessels with simultaneous balanced supplies to their two destinations.
5. A fraction of the circulating air mass flows throughout the lobar bronchial tree, while small fraction flows throughout the lobular bronchiolar trees and alveoli, each in the two opposing senses. One of these senses is directed towards the lobar periphery, towards the alveoli, while the other converse sense is directed towards the lobar roots and from here to the left or right main bronchus.
6. The extra-pulmonary airways: Right and Left Main Bronchi. Trachea and Larynx up to the Glottis complete the specific extra-pulmonary airway, also co-ordinated by the same Vagus Sympathetic command, which is a condition for its functional integration with the pulmonary lobes on one side and with the upper airways on the other side.
7. The Broncho-Tracheo-Larynx extra-pulmonary airway is basically a working space for transitory storage of alternating flowing masses of air. One is constituted by the sum of those fractions coming from the lobes after being used at the alveoli during the whole period of a Respiratory (Ventilatory) Cycle, where they are pressurised by contraction of the extra-pulmonary wall's muscles (Similar to a systole). This is a necessary condition for the used air ejection at he beginning of the Glottis relaxation (Expiration).
Once the ejection of the used air is completed and the muscle's relaxation is in progress, a relative vacuum is created, by which a similar mass of fresh air is aspired from the Pharynx, stored from the Inspiration of the former cycle.
8. It is now important to make clear that the mass of air inspired from the Atmosphere in each cycle does not arrive to the alveoli in the same cycle, but on the contrary, this mass is displaced by steps, during the periods of following cycles.
The first cyclic step is in the Naso-pharynx, where the air mass is stored, to be replaced during the next inspiration. Meanwhile this air mass receives a first degree of adaptation or "Organisation", before being aspired at the second next cycle, second cyclic step, by the Broncho-Tracheo-Larynx, where it will also remain for a period of acclimatisation, to then be aspired by the lobes, third cyclic step.
It is now when the air mass inspired from the Atmosphere, at least two cycles before the starting one, arrives to the mouths of the pulmonary lobes, to be aspired. This pre-conditioned air aspired by the lobes corresponds to the real dynamic process of pulmonary air renovation. It is now the real start of the new cycle for lobar circulation of the pre-adapted inspired air mass, to receive new degrees of adaptation, before being used, by fractions, at the lobular-bronchi and alveoli.
The Lung, better said, the pulmonary lobes in their ensemble perform the visceral dynamics leading to the total process known as Pulmonary Respiration. The extra-pulmonary airways are functional working cavities for atmospheric air circulation, adaptation and delivery to the pulmonary lobes, according to pulmonary demands.
Cardio-Circulatory and Pulmo-Respiratory "Systems", as they are known, are really sub-Systems of the whole organic conception for fluid circulation (Air and blood among others), to achieve a final objective. This objective is the supply of materials to the cells for their metabolism and removal of waste.
The difference in Design, structure and functional dynamics of these two integrated sub-Systems: Pulmo-Circulatory sub-System for Air circulation and Cardio-Circulatory sub-System for Blood-circulation responds to several factors:
1. The different physical behaviour of the fluids in liquid and gas state.
2. Blood is an organic tissue. Therefore, must circulate throughout a closed circuit.
3. Air is an inorganic mass of gases supplied by the Atmosphere, in the conditions of the individual's habitat.
4. The organic functional design demands physiologically balanced conditions in its internal media, anywhere anytime. Therefore, it is evident that inorganic atmospheric air must be physiologically adapted, "Organised" before meeting the venous blood circulating throughout the alveolar capillaries, to guarantee eupneic respiration.
5.Extra-pulmonary airways, lobar bronchi and lobular bronchioli afterwards, have as an important common task the adaptation of successive inspired masses of air to conditions required at the alveoli: mass per volume unit, temperature humidity.
6. Anatomy. Histology and embryological studies testify that each pulmonary lobe displays two well defined sectors:
a. The lobar bronchial tree, with its successive dichotic divisions up to the Central-lobular bronchioli.
b. The lobular bronchiolar trees, beginning at the central-lobular bronchioli, also with their dichotic divisions up to the respiratory bronchioli, the site of the alveoli.
These two sectors and kinds of pulmonary airways: lobar bronchial and lobular bronchiolar trees are fundamental for the cardio-pulmonary dynamic-functional integration, while the extra-pulmonary airways are very important for progressive adaptation of the atmospheric air conditions to organic needs.
These simultaneous mechanical functions announce two kinds of cyclic dynamics, which deserve to be differentiated, although only by abstraction, since they complement each other: Ventilation and Respiration strictus sense, each one with specific tasks and rhythm
7. The known cardiac and pulmonary rhythms are different although interrelated for metabolic demands, but cardiac and lobular-alveolo-capilary rhythms are specific and simultaneous in order to enable functional integration of the two named hemi-Systems.
8. I have demonstrated apart that the pulmonary lobuli have a specific rhythm which is parallel to that of the Heart, sine qua non condition to enable simultaneous circulation of the fluid masses of blood and air ejected in each cardio-lobular cycle throughout the alveolar-capillary units. This is the true pulmonary respiratory rhythm: the lobular alveolo-capillary rhythm, which is parallel to cell's respiration, at the other end of the whole integrated circuit.
Therefore, the lobular bronchiolar trees are functionally working small units designed for Heart and Lung Dynamic Integration for gas exchange; while the lobar bronchial trees are mainly concerned with final adaptation, division, distribution and supply of the demanded volume-mass of air to the lobuli. This is a role concerned with air renovation and simultaneous organic integration with the Atmosphere.
The traditionally known "respiratory rhythm", evident or apparent at the nasal and thoraco-abdominal level is only a rhythmic cycle for air renovation from the Atmosphere. Meanwhile, the inspired air is "organised" at successive levels, first by the Naso-Pharynx, then by the Broncho-Tracheo-Larynx extra-pulmonary airways, and afterwards by the proper Pulmonary Lobes. These facts identify this rhythm as a "Ventilatory rhythm" or rhythm for successive masses of air renovation and organic integration with the Atmosphere. Simultaneously, several lobular-alveolo-capillary cycles, with their own rhythm, parallel to cardiac rhythm, which are performed for specific gas exchange with the blood or pulmonary respiration strictus sense.
The facts named above, not perceived before by scientific researchers, are of the utmost importance and their ignorance has been cause of accidents, complications and even death, now avoidable if attention is devoted.
To complete this compared analysis and emphasise the perfection of the structural and functional Design of the living organism; it is necessary to emphasise the complementary role of the Thoracic and Abdominal walls. These walls are support of the Lung, avoiding physical overload, also generating forces to help other viscera.
Thoracic and abdominal walls are functionally integrated to the contained viscera via viscero-somatic reflex first and somato-somatic reflexes afterwards, making the Trunk. Head and Neck a viscero-somatic unit for vital functions.
Ventilation, or ventilatory cycles, is a cyclic process powered by the pulmonary lobes for renovation of successive masses of air from the Atmosphere, followed by their displacing and adaptation, step by step, finally to be finally aspired by the same pulmonary lobes, where they will receive further specific adaptation "organisation" with simultaneous division and distribution. Meanwhile, the intralobar mass of air remaining from each former cycle, which had received a final process of adaptation is ejected towards the lobuli for final use.
Therefore, the whole lobar process fills up, at least, two successive ventilatory cycles to guarantee continuity in space and time of delivery of an "organised air mass" to the lobuli.
The lobuli repeat the dynamics performed by the lobar tree, although with lower forces and fractionated air masses in a shorter space and time.
A similar mass of air to that inspired in each ventilatory cycle is used during the same period, in several small lobular cycles, with cardiac rhythm, to accomplish gas exchange with the blood. This use of air reflects metabolic demands and defines rhythm and volume of air renovation
Pulmonary Respiration is the cyclic process for gas exchange with the blood at the alveolo-capillary units. Consequently, this process demands simultaneous arrival, to the alveolo-capillary units, of proportional masses of blood and air, which means Lung and Heart Dynamic Integration at the Lobular-alveolar capillary units.
Pulmonary Respiration as defined above, is assisted by a complex process for atmospheric air intake , "organisation" transportation and delivery as far as the Centre Lobular Bronchioli.
This complex process also means Organic Integration of the Living Being with the Atmosphere and deserves its proper definition.
I propose the name of Ventilation or Ventilatory Cycle for each cycle of air renovation, reserving the name of Respiratory Cycle to each lobular-alveolo-capillary cycle and ventilo-Respiratory cycle for the whole simultaneous cyclic processes of air renovation from the Atmosphere and gas exchange with the blood, although bearing in mind that they are independent and work with different masses of air.
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