scholarly journals Phototropism of freshwater invertebrates in relation to their locomotion, habitats, respiration type, and diet

2020 ◽  
pp. 119-127
Author(s):  
Наталья Евгеньевна Николаева
Keyword(s):  
Respiratory System ◽  
Atmospheric Oxygen ◽  
Freshwater Invertebrates ◽  
Herbivorous Species

Установлено, что интенсивность и знак фототропизма у пресноводных беспозвоночных зависят от особенностей их передвижения, местообитания, питания и дыхания. У видов, активно плавающих в толще воды, наблюдались более высокие показатели положительного фототропизма, чем у бентосных. У животных, дышащих атмосферным кислородом, положительный фототропизм был выражен в большей степени, чем у животных с жаберным дыханием. При этом, чем больше потребность в кислороде или чем менее совершенны органы дыхания, тем ярче проявлялась положительная фотореакция. У хищников интенсивность положительного фототропизма выше, чем у растительноядных видов, и значительно выше, чем у детритофагов. У хищников обнаружена зависимость фотореакции от местообитания их пищевых объектов. We found that the intensity and polarity of phototropism in freshwater invertebrates depend on the characteristics of their locomotion, habitat, diet, and the type of respiration. Actively swimming species showed higher rates of positive phototropism than benthic ones. In animals breathing atmospheric oxygen, positive phototropism was more pronounced than in animals with gill respiration. At the same time, the higher the need for oxygen or the less perfect the respiratory system, the wider the positive photoreaction. In predators, the intensity of positive phototropism is higher than in herbivorous species and significantly higher than in detritophages. The photoreaction of predators is also dependant on the habitat of their food objects.

scholarly journals Refocusing Functional Anatomy and Immunology of the Respiratory Mucosa in the Advent of Covid-19

2021 ◽  
Author(s):  
Humphrey Simukoko
Keyword(s):  
Respiratory Tract ◽  
Respiratory System ◽  
Mammalian Cells ◽  
Atmospheric Oxygen ◽  
Severe Disease ◽  
Pulmonary Ventilation ◽  
Functional Anatomy ◽  
Upper Respiratory Tract ◽  
Mucosal Cells ◽  
Upper Respiratory

Atmospheric oxygen is an indispensable element required in order for mammalian cells to function normally. The mammalian respiratory system, through pulmonary ventilation and gas diffusion, provides the physical mechanisms by which oxygen gains access to all body cells and through which carbon dioxide is eliminated from the body. The network of tissues and organs of the respiratory system helps the mammalian body cells to absorb oxygen from the air to enable the tissues and organs to function optimally. The advent of the coronavirus disease 2019 (Covid-19) Pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has stimulated heightened and refocused interest in the study of various aspects of the respiratory system. The SARS-CoV-2 targets the respiratory system mucosal cells and in a cascade of biological processes curtails the ability of the respiratory system to absorb and deliver oxygen to the pulmonary blood and body cells often resulting in severe disease and/or death. The mucosa and submucosa of the respiratory tract are adapted to provide both innate and adaptive immune defense mechanisms against pathogens including the SARS-CoV-2. The entire respiratory tract is covered by a mucosa that transitions in its structural and functional characteristics from the upper respiratory tract to the lower respiratory tract. This chapter provides an overview of the functional anatomy and immunology of the respiratory tract covering the mucosa from the upper respiratory tract all the way up to the alveolar epithelium. In the advent of the covid-19 pandemic, a broader perspective and understanding of the anatomy and immunology of the respiratory tract will enable general readers and researchers to fully appreciate the discourse in covid-19 research as it affects the respiratory tract.

The Evolution of Unidirectional Pulmonary Airflow

Physiology ◽  
2015 ◽  
Vol 30 (4) ◽  
pp. 260-272 ◽  
Author(s):  
C. G. Farmer
Keyword(s):  
Gas Exchange ◽  
Respiratory System ◽  
Aerobic Capacity ◽  
Atmospheric Oxygen ◽  
Work Of Breathing ◽  
Large Body ◽  
Blood Gas ◽  
Gas Barrier ◽  
Unidirectional Flow ◽  
Selection For

Conventional wisdom holds that the avian respiratory system is unique because air flows in the same direction through most of the gas-exchange tubules during both phases of ventilation. However, recent studies showing that unidirectional airflow also exists in crocodilians and lizards raise questions about the true phylogenetic distribution of unidirectional airflow, the selective drivers of the trait, the date of origin, and the functional consequences of this phenomenon. These discoveries suggest unidirectional flow was present in the common diapsid ancestor and are inconsistent with the traditional paradigm that unidirectional flow is an adaptation for supporting high rates of gas exchange. Instead, these discoveries suggest it may serve functions such as decreasing the work of breathing, decreasing evaporative respiratory water loss, reducing rates of heat loss, and facilitating crypsis. The divergence in the design of the respiratory system between unidirectionally ventilated lungs and tidally ventilated lungs, such as those found in mammals, is very old, with a minimum date for the divergence in the Permian Period. From this foundation, the avian and mammalian lineages evolved very different respiratory systems. I suggest the difference in design is due to the same selective pressure, expanded aerobic capacity, acting under different environmental conditions. High levels of atmospheric oxygen of the Permian Period relaxed selection for a thin blood-gas barrier and may have resulted in the homogeneous, broncho-alveolar design, whereas the reduced oxygen of the Mesozoic selected for a heterogeneous lung with an extremely thin blood-gas barrier. These differences in lung design may explain the puzzling pattern of ecomorphological diversification of Mesozoic mammals: all were small animals that did not occupy niches requiring a great aerobic capacity. The broncho-alveolar lung and the hypoxia of the Mesozoic may have restricted these mammals from exploiting niches of large body size, where cursorial locomotion can be advantageous, as well as other niches requiring great aerobic capacities, such as those using flapping flight. Furthermore, hypoxia may have exerted positive selection for a parasagittal posture, the diaphragm, and reduced erythrocyte size, innovations that enabled increased rates of ventilation and more rapid rates of diffusion in the lung.

Air Pollution's Effects on the Human Respiratory System

2016 ◽  
Vol 44 (5) ◽  
pp. 383-395 ◽  
Author(s):  
Nehaarika Kantipudi ◽  
Vivek Patel ◽  
Graham Jones ◽  
Markad V. Kamath ◽  
Adrian R. M. Upton
Keyword(s):  
Respiratory System ◽  
Human Respiratory System

Prognostic role of results of dynamic capnography in integral assessment of parameters of respiratory system in 6-minute walk test in patients with chronic heart failure

2020 ◽  
Vol 28 (3) ◽  
pp. 290-299
Author(s):  
Kira A. Ageeva ◽  
Evgenii V. Filippov
Keyword(s):  
Respiratory System ◽  
Prognostic Significance ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Control Group ◽  
Walk Test ◽  
Ventricular Ejection Fraction ◽  
6Mwt Distance ◽  
6 Minute Walk Test ◽  
Minute Walk

Aim. To study the prognostic value of the results of dynamic capnography in the complex assessment of parameters of the respiratory system in 6-minute walk test in patients with chronic heart failure (CHF). Materials and Methods. 73 Patients were examined: the group of study included 48 patients with IIA or IIB stage CHF (mean age 57.94.6 years, 23 men), the control group included 25 practically healthy volunteers (mean age 47.63.5 years, 9 men). The patients were conducted complex determination of parameters of the respiratory system: clinical scaling before and after 6-minute walk test (6MWT), instrumental examinations including spirometry, capnography and pulse oximetry before, during and after physical activity. The analysis of survival was conducted on the basis of the dynamic follow-up of patients within 5 years (60 months). Results. In the analysis of parameters of dyspnea at rest, all the parameters were higher in the group of patients with CHF (р0.05). The distance walked by the patients with CHF in 6 minutes was 488.2390.84 m, which was significantly less than in the control group (815.6053.89 m, р=0.009). Dyspnea as the cause of stoppage/slowing down of walking in 6MWT, was also more often recorded in patients with CHF (93.83.0% and 48.05.1%, р=0.049). Besides, in 6MWT the patients noted: weakness in legs (50.15.0% in the group of CHF and 40.05.0% in the control group, р=0.014), palpitation (29.04.6% and 20.04.1%, respectively, р=0.004). Worsening of dyspnea parameters in 6MWT was more evident in patients with CHF than in the control group (р0.01). In the CHF group, hypocapnic type of ventilation was revealed in 6MWT, analysis of РЕТСО2 trend graphs revealed a wave-like increase in the parameters, the so called periodic breathing (PB). CO2 trend was recorded in CHF group in 58.31.0% of cases (the difference with the control group with р=0.046), the trend of heart rate in 18.80.3% of cases (р=0.027). Cox proportional hazards regression analysis of mortality in patients with CHF showed a prognostic significance of a complex model comprising the following parameters of a patient: body mass index (р=0.005), left ventricular end-diastolic dimension (р=0.034), left ventricular end-systolic dimension (р=0.002), left ventricular ejection fraction (р=0.041), 6MWT distance (р=0.004), desaturation (р=0.009), and the presence of signs of PB during 6MWT (р=0.005). Model coefficients were statistically significant at р0.0001. Conclusions. Dynamic capnography and pulse oximetry allow to identify signs of PB in patients with CHF during 6MWT which may deepen a complex assessment of parameters of the cardio-respiratory system in patients with CHF in order to determine tolerance to physical exercise as well as the effectiveness of the conducted treatment. Complex assessment of survival of patients with CHF showed prognostic significance of the following parameters of a patient: body mass index, left ventricular end-diastolic dimension, left ventricular end-systolic dimension, left ventricular ejection fraction, 6MWT distance, desaturation, PB during 6MWT.

Phanerozoic Oxygen

2017 ◽  
Author(s):  
Donald Eugene Canfield
Keyword(s):  
Oxygen Consumption ◽  
Organic Carbon ◽  
Sea Level ◽  
Time Scale ◽  
Atmospheric Oxygen ◽  
Sea Level Change ◽  
Oxygen Production ◽  
Level Change ◽  
History Of ◽  
Geologic Processes

This chapter discusses the modeling of the history of atmospheric oxygen. The most recently deposited sediments will also be the most prone to weathering through processes like sea-level change or uplift of the land. Thus, through rapid recycling, high rates of oxygen production through the burial of organic-rich sediments will quickly lead to high rates of oxygen consumption through the exposure of these organic-rich sediments to weathering. From a modeling perspective, rapid recycling helps to dampen oxygen changes. This is important because the fluxes of oxygen through the atmosphere during organic carbon and pyrite burial, and by weathering, are huge compared to the relatively small amounts of oxygen in the atmosphere. Thus, all of the oxygen in the present atmosphere is cycled through geologic processes of oxygen liberation (organic carbon and pyrite burial) and consumption (weathering) on a time scale of about 2 to 3 million years.

Sign in / Sign up

Export Citation Format

Share Document