Mammalian respiratory system

Figure 3.10 The structure of the mammalian respiratory system (A) trachea, (B) bronchiole, (C) alveolar sac with blood supply, (D) arrangement of blood vessels around alveoli, (E) arrangement of cells and airspaces in alveoli showing the large surface area available for absorption, (F) cellular structure of alveolus showing the close association between (G) the endothelial cell of the capillary (H) with erythrocytes and (I) the epithelial cell of the alveolar sac. The luminal side of the epithelial cell is bathed in fluid, which also facilitates absorption and gaseous exchange. Source From Ref. 1.

Different irritant chemicals affect parts of the mammalian respiratory system differently. The upper respiratory tract of the mammalian lung is affected by chemicals such as aldehydes, ammonia, alkaline dust, chromic acid, sulfur dioxide, sulfur trioxide, hydrogen fluoride, hydrogen chloride, and ethylene oxide). It is now known that many fluorine-containing organic compounds, such as chlorofluorocarbons (CFCs), have played a major role in the asthmatic deaths... 

Pinkerton KE Joad JP (2000) The mammalian respiratory system and critical windows of exposure for children s health. Environ Health Perspect, 108(Suppl 3) 457-462. 

Jones, J.H. (1998). Optimization of the mammalian respiratory system symmorphosis versus single species adaptation. Comp. Biochem. Physiol. 120B 125-138. 

Taylor, C.R., E.R. Weibel, R.H. Karas, and H. Hoppeler (1987). Adaptive variation in the mammalian respiratory system in relation to energy demand. Resp. Physiol. 69 1-127. 

Taylor, C.R., G.M.O. Maloiy, E.R. Weibel, V.A. Langman, J.M.Z. Kamau, H.J. Seeherman, and N.C. Eleglund (1981). Design of the mammalian respiratory system. III. Scaling maximum aerobic capacity to body mass wild and domestic mammals. Respir. Physiol. 44 25-37. 

To maintain its primary function as an organ of gas exchange, the mammalian respiratory system must be able to defend itself from constant assault of hazardous agents that enter the body by this route of exposure. When these normal pulmonary defenses are compromised, inhaled toxic substances have the potential for initiating or aggravating existing lung disease. The health effects associated with airborne... 

B. Different Type h Cytochromes in Mammalian Respiratory Systems... 

As noted above, cytochrome b in the mammalian respiratory system is firmly bound to the mitochondrial membrane and cannot be solubilized without using detergents such as cholate. It is thus interesting that a cytochrome b-like pigment, cytochrome b-563, is easily extracted from the larvae and pupae of the housefly, Musca domestica, with a simple salt solution, but it cannot be extracted from the adult flies under the same conditions. The cytochrome is obtained as a crystalline preparation after purification by the chromatography on DEAE-cellulose (78,84). The crystalline cytochrome b-563 has a similar spectral property to mammalian cytochrome b and shows absorption peaks at 563, 530, and 428.5 nm in the reduced state. Contrary to purified mammalian cytochrome b, this cytochrome does not combine with carbon monoxide and exists as monomer species in the solution without detergent. 

The process of combustion of materials enriched with yttrium seems to be a risk factor as a source of flammable dusts. Yttrium oxide, yttrium chloride, yttrium citrate, and certain other yttrium compounds may cause chronic pathological effects in different parts of the mammalian respiratory system, according to the results of experimental studies carried out in rats, mice, guinea pigs, and rabbits. Therefore, a higher risk for human health may be... 

Taylor, C.R. and Weibel, E.R. 1981. Design of the mammalian respiratory system I Problem and strategy. Respir. Physiol. 44 1-10. 

The mammalian immune system protects the body from infection by many complex strategies. The most vigorous defense is performed by white blood cells known as granulocytes. These cells consume oxygen in response to microbial infections. This oxidative process, called the respiratory burst, has recently been proven to produce stabilized hvDOchlorite antimicrobials (bredominantlv bv neutroDhils) and stabilized... 

Note that both acetogenins and styryl-lactones are cytotoxic for mammalian cells, as the result of distinct biochemical pathways, which, however, have their molecular origin near or in the mitochondrial membrane and/or the mitochondrial respiratory system (61,62). Acetogenins were first characterized as the active principles responsible for... 

The nasal system of guinea pigs is more complex than that of other mammalian species, including humans. In those species the fraction of agent absorbed or deposited in the upper respiratory system may be smaller. Consequently, the middle and lower respiratory systems are likely to be exposed to a larger portion of the agent. 

The terminal respiratory systems of some bacteria (Dolin, 1961), protozoa (trypanosomes) (Grant, Sargent and Ryley, 1961), and helminths Ascaris) (Kmetec and Bueding, 1961) are insensitive to concentrations of cyanides and antimycin A that are lethal to mammalian cells. It is evident that they can dispense with the whole respiratory chain after cytochrome b. However, they are particularly sensitive to vitamin K analogues, e.g. 2-hydroxy-3-2 -methyloctyl-1,4-naphthoquinone. 

Toxic effects of nickel to humans and laboratory mammals are documented for respiratory, cardiovascular, gastrointestinal, hematological, musculoskeletal, hepatic, renal, dermal, ocular, immunological, developmental, neurological, and reproductive systems. Nickel toxicity in mammals is governed by the chemical form of nickel, dose, and route of exposure. Mammalian exposure to nickel by inhalation or cutaneous contact was more significant than oral exposure. To protect humans and other mammals against respiratory effects, proposed air-quality criteria are 0.01 to less than... 

HCN is a systemic poison toxicity is due to inhibition of cytochrome oxidase, which prevents cellular utilization of oxygen. Inhibition of the terminal step of electron transport in cells of the brain results in loss of consciousness, respiratory arrest, and ultimately, death. Stimulation of the chemoreceptors of the carotid and aortic bodies produces a brief period of hyperpnea cardiac irregularities may also occur. The biochemical mechanisms of cyanide action are the same for all mammalian species. HCN is metabolized by the enzyme rhodanese which catalyzes the transfer of sulfur from thiosulfate to cyanide to yield the relatively nontoxic thiocyanate. 

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