A Passive Model of the Heat, Oxygen and Carbon Dioxide Transport in the Human Body

2009 ◽  
Author(s):  
Cyro Albuquerque-Neto ◽  
Jurandir Itizo Yanagihara
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Human Body ◽  
Circular Cross Section ◽  
The Body ◽  
Heat Equations ◽  
Carbon Dioxide Transport ◽  
Small Vessels ◽  
Hands And Feet ◽  
Dissociation Curves

The aim of this work is the development of a mathematical model which integrates a model of the human respiratory system and a model of the human thermal system. Both models were previously developed at the same laboratory, based on classical works. The human body was divided in 15 segments: head, neck, trunk, arms, forearms, hands, thighs, legs and feet. Those segments have the form of a cylinder (circular cross-section) or a parallelogram (hands and feet) with the following tissue layers: muscle, fat, skin, bone, brain, lung, heart and viscera. Two different geometries are used to model the transport of mass and heat in the tissues. For the mass transfer, those layers are considered as tissue compartments. For the heat transfer, the body geometry is taken into account. Each segment contains an arterial and a venous compartment, representing the large vessels. The blood in the small vessels are considered together with the tissues. The gases are transported by the blood dissolved and chemically reacted. Metabolism takes place in the tissues, where oxygen is consumed generating carbon dioxide and heat. In the lungs, mass transfer happens by diffusion between an alveolar compartment and several pulmonary capillaries compartments. The skin exchanges heat with the environment by convection, radiation and evaporation. The differential transport equations were obtained by heat and mass balances. The discretization heat equations were obtained applying the finite volume method. The regulation mechanisms were considered as model inputs. The results show three different environment situations. It was concluded that the gas transport is most influenced by the temperature effects on the blood dissociation curves and the metabolism rise in a cold environment by shivering.

scholarly journals Oxygen and Carbon Dioxide Transport Characteristics of the Blood of the Nile Monitor Lizard (Varanus Niloticus)

1987 ◽  
Vol 130 (1) ◽  
pp. 27-38
Author(s):  
JAMES W. HICKS ◽  
ATSUSHI ISHIMATSU ◽  
NORBERT HEISLER
Keyword(s):  
Carbon Dioxide ◽  
Haemoglobin Concentration ◽  
Oxygen Affinity ◽  
Total Blood ◽  
Carbon Dioxide Transport ◽  
Monitor Lizard ◽  
The Right ◽  
Dissociation Curves

Oxygen and carbon dioxide dissociation curves were constructed for the blood of the Nile monitor lizard, Varanus niloticus, acclimated for 12h at 25 and 35°C. The oxygen affinity of Varanus blood was low when Pco2 w a s in the range of in vivo values (25°C: P50 = 34.3 at PCOCO2 = 21 mmHg; 35°C: P50 = 46.2 mmHg at PCOCO2 = 35 mmHg; 1 mmHg = 133.3 Pa), and the oxygen dissociation curves were highly sigmoidal (Hill's n = 2.97 at 25°C and 3.40 at 35°C). The position of the O2 curves was relatively insensitive to temperature change with an apparent enthalpy of oxygenation (ΔH) of −9.2kJ mol−1. The carbon dioxide dissociation curves were shifted to the right with increasing temperature by decreasing total CCOCO2 at fixed PCOCO2, whereas the state of oxygenation had little effect on total blood CO2 content. The in vitro buffer value of true plasma (Δ[HCO3−]pl/-ΔpHpl) rose from 12.0 mequiv pH−1−1 at 25°C to 17.5 mequiv pH−11−1 at 35°C, reflecting a reversible increase of about 30% in haemoglobin concentration and haematocrit levels during resting conditions in vivo.

The Physiology of Carbon Dioxide Transport in Insect Blood

1950 ◽  
Vol 27 (2) ◽  
pp. 158-174 ◽  
Author(s):  
L. LEVENBOOK
Keyword(s):  
Carbon Dioxide ◽  
Dissociation Constant ◽  
Temperature Coefficient ◽  
Carbonic Acid ◽  
Apparent Dissociation Constant ◽  
Carbon Dioxide Transport ◽  
High Co2 ◽  
The Third ◽  
A Value ◽  
Dissociation Curves

1. The pH of the blood of the third instar Gastrophilus larva is 6.64 at 38° C. with a pH-temperature coefficient of -0.007 Per 1° C. rise in temperature. 2. The total CO2 content of the blood varies from 40.6 to 131.4 vol. % with an average of 72.4 vol. %. The CO2 content of the tissues minus the cuticle is very close to, and follows the variations in, the CO2 content of the blood. 3. The CO2 tension in the blood is from 300 to 500 mm. Hg. From 30 to 50% of the CO2 is in solution, the rest in the form of bicarbonate. Carbamate formation does not occur in the blood. 4. The ‘apparent’ dissociation constant for carbonic acid, (pK'1), has a value of 6.08 (S.D. ±0.06) at 38° C. and 6.19 (s.d. ±0.13) at 16° C. 5. CO2 dissociation curves have been drawn for 38 and 16° C. The slope of the curves indicates that the whole of the CO2 is given off at zero CO2 tension, and that the blood is adapted for functioning at high CO2 tensions.

The mechanisms which affect the periodic cycle of Pacific Wuchereria bancrofti microfilariae

1981 ◽  
Vol 55 (2) ◽  
pp. 95-100 ◽  
Author(s):  
F. Hawking ◽  
Tinousi Jennings ◽  
F. J. Louis ◽  
E. Tuira
Keyword(s):  
Carbon Dioxide ◽  
Circadian Rhythm ◽  
Body Temperature ◽  
Sodium Bicarbonate ◽  
Human Body ◽  
Venous Blood ◽  
Wuchereria Bancrofti ◽  
Early Morning ◽  
The Body ◽  
Small Rise

ABSTRACT1. Investigations were made of the effect of various procedures in raising or lowering the microfilaria count of Pacific type Wuchereria bancrofti in the peripheral blood.2. Raising the body temperature in the early morning was followed by a moderate fall in the counts. Breathing increased oxygen, or reduced oxygen (hypoxia) or increased carbon dioxide, or the ingestion of sodium bicarbonate produced no consistent and significant changes in the count. Ingestion of glucose (in one volunteer) was followed by a small rise in the count. Muscular exercise was followed by a fall in the count, which is interpreted as probably being a response to a lower concentration of oxygen in the venous blood returning to the lung.3. It has not been possible to identify the physiological components of the circadian rhythm of the human body which entrain the cycle of these microfilariae. Attempts to obtain evidence incriminating the stimuli described above have been unsuccessful.

scholarly journals CLINICAL SIGNIFICANCE OF CARDIAC AND RESPIRATORY ADJUSTMENTS IN CHRONIC ANEMIA

Blood ◽  
1948 ◽  
Vol 3 (4) ◽  
pp. 329-348 ◽  
Author(s):  
HERRMAN L. BLUMGART ◽  
MARK D. ALTSCHULE
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Carbonic Anhydrase ◽  
Carrying Capacity ◽  
Vital Capacity ◽  
The Body ◽  
Carbon Dioxide Transport ◽  
Chronic Anemia ◽  
Arterial Blood ◽  
Oxygen Carrying Capacity

Abstract The cardiac and respiratory adjustments in chronic anemia and their clinical manifestations have been reviewed. When the oxygen carrying capacity of the blood is diminished, an adequate supply of oxygen to the tissues is maintained by an increased cardiac output, an increased velocity of blood flow, and a relatively more complete abstraction of the oxygen from the blood as it passes through the capillaries. With the increased blood flow, the average peripheral resistance is decreased but the state of the small blood vessels is not uniform everywhere; the blood flow in the hands and kidneys, for instance, may be reduced, while that of other parts of the body is increased. The total oxygen consumption of the body in anemia is not strikingly altered. The blood volume generally is slightly reduced but the plasma volume is normal. The deviations from the normal values vary from patient to patient, but generally are definite when the hemoglobin values are less than 50 per cent and are greatest at the lowest levels of hemoglobin concentration. The close interrelationship between the cardiovascular and respiratory systems is exemplified by the coincident changes in the respiratory system in anemia. The rate and depth of respiration often are increased together with a lowering in the vital capacity and its subdivisions, the reserve and complemental air volumes. The resid- ual air is somewhat increased. These deviations from the normal are similar to those observed in pulmonary congestion or edema and denote a loss of elasticity and expansibility favoring the occurrence of exertional dyspnea. The arterial blood saturation is usually normal at rest but, during exertion, a significant lowering becomes apparent. The importance of hemoglobin in the transport of carbon dioxide is reviewed; the decreased availability of hemoglobin as a buffer in carbon dioxide transport in anemia is compensated by the increased ventilation of the blood in the lungs, rendering the arterial blood somewhat alkalotic. The red cells also play an important role in regard to the respiratory enzyme, carbonic anhydrase. In the anemias due to blood loss, malnutrition, chronic infection, uremia, or leukemia, the blood carbonic anhydrase activity is parallel to the decrease in hemoglobin level leading to a deficiency not only of oxygen carrying capacity but also a decreased ability to absorb carbon dioxide from the tissues and to release it in the lungs. The following factors, many of which are closely interrelated, are operative in the production of dyspnea in anemic patients: the increased respiratory minute volume, the decreased vital capacity and its subdivisions, the abnormalities in carbon dioxide transport and dissociation, the reduced arterial oxygen capacity and the decreased blood oxygen saturation during effort, and the frequently observed elevated blood lactic acid values. The symptoms and signs exhibited by anemic patients, including palpitation and breathlessness on exertion, tachycardia, cardiac dilatation and hypertrophy, are described. In addition to an apical systolic murmur, other systolic and diastolic murmurs are occasionally heard. The arterial blood pressure is frequently lowered in anemia; the venous pressure is generally within the limits of normal. Electrocardiographic abnormalities occur in approximately one-quarter of anemic patients but are minor and not specific in character. The occurrence of angina pectoris, congestive failure, and intermittent claudication in some patients with the development of anemia, and disappearance of these conditions as the anemia is alleviated, is discussed with particular reference to the underlying physiologic mechanisms.

scholarly journals IN VITRO INTERACTIONS BETWEEN OXYGEN AND CARBON DIOXIDE TRANSPORT IN THE BLOOD OF THE SEA LAMPREY (PETROMYZON MARINUS)

1992 ◽  
Vol 173 (1) ◽  
pp. 25-41 ◽  
Author(s):  
R. A. Ferguson ◽  
N. Sehdev ◽  
B. Bagatto ◽  
B. L. Tufts
Keyword(s):  
Carbon Dioxide ◽  
Blood Cell ◽  
Red Blood Cells ◽  
Red Blood Cell ◽  
Whole Blood ◽  
Blood Cells ◽  
Sea Lamprey ◽  
Carbon Dioxide Transport ◽  
Dissociation Curves

In vitro experiments were carried out to examine the interactions between oxygen and carbon dioxide transport in the blood of the sea lamprey. Oxygen dissociation curves for whole blood obtained from quiescent lampreys had Hill numbers (nH) ranging from 1.52 to 1.89. The Bohr coefficient for whole blood was -0.17 when extracellular pH (pHe) was considered, but was much greater (-0.63) when red blood cell pH (pHi) was considered. The pHi was largely dependent on haemoglobin oxygen- saturation (SO2) and the pH gradient across the red blood cell membrane was often reversed when PCO2 was increased and/or SO2 was lowered. The magnitude of the increase in pHi associated with the Haldane effect ranged from 0.169 pH units at 2.9 kPa PCO2 to 0.453 pH units at a PCO2 of 0.2 kPa. Deoxygenated red blood cells had a much greater total CO2 concentration (CCO2) than oxygenated red blood cells, but the nonbicarbonate buffer value for the red blood cells was unaffected by oxygenation. Plasma CCO2 was not significantly different under oxygenated or deoxygenated conditions. Partitioning of CO2 carriage in oxygenated and deoxygenated blood supports recent in vivo observations that red blood cell CO2 carriage can account for much of the CCO2 difference between arterial and venous blood. Together, the results also suggest that oxygen and carbon dioxide transport may not be tightly coupled in the blood of these primitive vertebrates. Finally, red cell sodium concentrations were dependent on oxygen and carbon dioxide tensions in the blood, suggesting that sodium-dependent ion transport processes may contribute to the unique strategy for gas transport in sea lamprey blood.

scholarly journals Formulation of Generalized Mass Transfer Correlations for Blood Oxygenator Design

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Kenny W. Q. Low ◽  
Raoul Van Loon ◽  
Samuel A. Rolland ◽  
Johann Sienz
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Sherwood Number ◽  
Concentration Field ◽  
Transverse Flow ◽  
Gas Transfer ◽  
Carbon Dioxide Transport ◽  
Blood Oxygenator ◽  
Geometrical Features ◽  
Local Mass Transfer

This paper numerically investigates non-Newtonian blood flow with oxygen and carbon dioxide transport across and along an array of uniformly square and staggered arranged fibers at various porosity (ε) levels, focussing on a low Reynolds number regime (Re < 10). The objective is to establish suitable mass transfer correlations, expressed in the form of Sherwood number (Sh = f(ε, Re, Sc)), that identifies the link from local mass transfer investigations to full-device analyses. The development of a concentration field is initially investigated and expressions are established covering the range from a typical deoxygenated condition up to a full oxygenated condition. An important step is identified where a cut-off point in those expressions is required to avoid any under- or over-estimation on the Sherwood number. Geometrical features of a typical commercial blood oxygenator is adopted and results in general show that a balance in pressure drop, shear stress, and mass transfer is required to avoid potential blood trauma or clotting formation. Different definitions of mass transfer correlations are found for oxygen/carbon dioxide, parallel/transverse flow, and square/staggered configurations, respectively. From this set of correlations, it is found that transverse flow has better gas transfer than parallel flow which is consistent with reported literature. The mass transfer dependency on fiber configuration is observed to be pronounced at low porosity. This approach provides an initial platform when one is looking to improve the mass transfer performance in a blood oxygenator without the need to conduct any numerical simulations or experiments.

The origins of societies

1997 ◽  
Author(s):  
John Maynard Smith ◽  
Eors Szathmary
Keyword(s):  
Carbon Dioxide ◽  
Sex Ratio ◽  
Human Body ◽  
Somatic Cells ◽  
Egg Laying ◽  
The Body ◽  
Narrow Channels ◽  
The Individual ◽  
Animal Societies

The heat generated within a mound of the termite Macrotermes is carried upwards by a central air duct. The air then travels down along narrow channels close to the surface of the mound, where it is cooled, and where, as in a lung, oxygen and carbon dioxide are exchanged. The whole mound is an airconditioning system. Although the mound resembles a human building in having features ensuring the comfort of its inhabitants, it differs in that not one of its builders had a picture of the completed structure before building started. The structure emerged from the rule-governed behaviour of tens of thousands of interacting workers. In this, the mound resembles a human body rather than a human building. The body is built by the rule-governed actions of millions of cells. Nowhere is there anything resembling a blueprint of the body. At most, the genome is a set of instructions for making a body: it is not a description of a body. The resemblance between the development of an insect colony and of an organism has led to the concept of a ‘superorganism’. The analogy has some value. To the extent that individual ants, bees or termites have lost the capacity to reproduce, they can propagate their genes only by ensuring the success of the colony, just as somatic cells can propagate theirs only by ensuring the success of the organism. Hence, the colony can be expected to have features adapted to ensure its success, and it is reasonable to apply concepts of optimization to it, rather than to the individual—as was done, for example, by Oster & Wilson (1978) in their book on insect caste systems. But for our purposes the concept of a super organism is of little use. To understand the origins of animal societies, we must ask how individuals capable of reproduction came to cooperate to the extent that most of them lost the ability to reproduce. To understand their maintenance, we must explain why they are not disrupted by cheating. Unlike somatic cells, the individual workers, although related, are not genetically identical. We would therefore expect within-colony conflict to be widespread, as indeed it is: examples discussed below concern egg laying by workers, and conflict over the sex ratio.

The Respiratory System

2019 ◽  
Author(s):  
Zerlina Wong ◽  
Michael Nurok
Keyword(s):  
Carbon Dioxide ◽  
Respiratory System ◽  
Airway Resistance ◽  
Respiratory Mechanics ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Lung Compliance ◽  
The Body ◽  
Elastic Recoil ◽  
Carbon Dioxide Transport ◽  
Pulmonary Vasoconstriction

The pulmonary system is crucial for survival. Managing respiratory mechanics and airway requires a sophisticated understanding of pulmonary physiology. This chapter discusses the ways in which oxygen is brought into the body and carbon dioxide is expelled and reviews the principles of respiratory mechanics, including lung compliance, airway resistance, chemoreceptor and mechanoreceptor control of ventilation, hypoxic pulmonary vasoconstriction, distribution of perfusion, and other properties that affect oxygen and carbon dioxide transport. The respiratory system exists in a state of equilibrium, where the inward elastic recoil of the lungs is balanced with the outward elastic recoil of the chest wall. Airway resistance and compliance are important factors that affect ventilation and air movement. This chapter reviews the role that chemoreceptors and mechanoreceptors have on controlling ventilation, as well as the effects that hypercarbia and hypoxemia have on pulmonary and cerebral circulation, and the Bohr and Haldane effects that elucidate understanding of the hemoglobin dissociation curve. These principles all inform the care of patients who require mechanical ventilation, as we endeavor to support them through their surgery or intensive care stay. This review contains 7 figures and 38 references. Key Words: apneic oxygenation, Bohr effect, chemoreceptors, compliance, Haldane effect, hypoxic pulmonary vasoconstriction, resistance, respiratory mechanics, ventilation-perfusion

Numerical Simulation of Radiation Heat Transfer of the Human Body for Determining Its Radiation Coefficient

2011 ◽  
Author(s):  
Ahmad Najjaran ◽  
Ali R. Tahavvor ◽  
Abdolkarim Najjaran ◽  
Mohammad A. Ahmadfard
Keyword(s):  
Heat Transfer ◽  
Human Body ◽  
Radiation Heat Transfer ◽  
Convection Heat Transfer ◽  
The Body ◽  
Heat Radiation ◽  
Radiation Heat ◽  
Radiation Heat Flux ◽  
Radiation Coefficient ◽  
Hands And Feet

Radiation heat transfer coefficient of the human body is one of the most important factors in the field of human skin health. In this paper, the radiation coefficient of the body is calculated by considering external heat radiation of body with the infinite surrounding. At first a human body is designed, and then analysis is done on it. Two segments are assumed for human body (standing and supine). In these segments hands and feet are supposed to be totally open and stretched. In standing segment, soles and in supine segment, the entire back of the body are in contact with the ground and so don’t have heat transfer. The calculation of the results is done by weighted area average method. Radiation coefficient and radiation heat flux are calculated in various emissivity. Because of existence of air around the body in reality, the convection heat transfer is also assumed for human body. Finally two formulas are reported for these segments.

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