China
Africa
Explore chapters and articles related to this topic
Effects of Nanomaterials on the Body Systems of Fishes
Published in Julián Blasco, Ilaria Corsi, Ecotoxicology of Nanoparticles in Aquatic Systems, 2019
Richard D. Handy, Genan Al-Bairuty
The gills are the major organs for respiratory gas exchange and osmoregulation in fish. Similar to traditional chemicals, the concern is that waterborne exposure to ENMs may compromise the gill epithelium such that the animals suffer hypoxia and/or life-threatening osmotic disturbances to the blood. The freshwater-adapted fish gill is regarded as one of the tightest epithelia in animal biology. Nonetheless, acute respiratory distress has been documented. Smith et al. (2007) showed that waterborne exposure to 1 mg L−1 of single-walled carbon nanotubes (SWCNTs, length 5–30 µm) in rainbow trout (Oncorhynchus mykiss) causes an increase in the ventilation rate and coagulation of the ENMs in the gill mucus. Overt gill pathology has also been observed in rainbow trout with high mg L−1 concentrations of TiO2 ENMs (TiO2 particle diameter, 21 nm, Federici et al. 2007). Perhaps a more interesting concern is whether or not gill injury is repairable, and whether or not there are nano-specific pathologies in the gill that are not seen with other chemicals.
Respiratory and Cardiovascular Responses
Published in Alan G. Heath, Water Pollution and Fish Physiology, 2018
The gills consist of horizontal flat filaments which are supported in the water stream by the bony gill arches. On the filaments are found the secondary lamellae which range in frequency along a given filament from 10–60/mm; the higher numbers are found in the more active species (Hughes, 1982). Because of the structure of the gills, they provide a large surface area for the movement of oxygen, carbon dioxide, electrolytes, water, ammonia, and hydrogen ions between the blood and water. Thus, the gills are really a multipurpose organ directly involved in a variety of functions including respiratory gas exchange, osmoregulation, acid-base balance, and nitrogenous waste excretion. The majority of these fluxes of chemicals take place across the epithelial surface of the lamellae, which because of its multiple function, has been referred to as the “renaissance epithelium” (Bentley, 1980).
Adaptation of Life to Extreme Conditions
Published in Michael Hehenberger, Zhi Xia, Huanming Yang, Our Animal Connection, 2020
Michael Hehenberger, Zhi Xia, Huanming Yang
It is interesting how gills extract dissolved oxygen from water and excrete carbon dioxide. In fish (and mollusks such as octopus and squid), the efficiency of the gills is enhanced by a countercurrent mechanism: the water passes over the gills in the opposite direction to the flow of blood through them. This mechanism is very efficient and permits recovery of about 90% of the dissolved oxygen in water.32 The gills are composed of comb-like filaments, the gill lamellae, which help increase their surface area for oxygen exchange.
Seasonal variation and impact of linear alkyl sulphonate (LAS) toxicity on Nile tilapia, Oreochromis niloticus in two Nile Delta Lagoons, Egypt
Published in Chemistry and Ecology, 2022
Mohamed A. Okbah, Asmaa M. R. Gouda, Ahmed E. Hagras, Maie I. El-Gammal
Fish gills are the target organ for water pollutants because it usually in direct contact with the surrounding water, so they are influenced by either chemical or physical changes causing changes in their morphology. Thus, histological evaluation of gills is effective in environmental monitoring programs [36]. The normal structure of gills tissue consists of several cartilaginous arches, each arch bears pairs of processes called primary lamellae which serve more support for thin expansions called secondary lamellae for respiration. It is noticed that gill’s histology in River Nile fish showed the roughly normal structure, while that of fish sampled from both Burullus and Edku Lakes showed some abnormalities represented in marked degenerative changes, adhesion between lamellae and desquamative, complete loss of secondary lamellae associated with marked proliferation of mucous cells, marked infiltration of leukocytic cells and telangiectasis of the capillary of the secondary lamellae (Figures 6–9). The observed histological changes may be due to increased LAS concentrations in both lakes water than River Nile, these results agree with [37,38].