The organism of Uromastyx aegyptius as any other lizard can function effectively depending on the regulated work of such specific lizards’ organs as salt glands which allow them to surviving under the extreme environmental conditions. The role of a salt gland in the lizards’ metabolism and excreting salts is substantial. The specific conditions of reptiles’ living and the lack of fresh water make lizards follow salty diets with the large amount of salty plants. As a result, lizards as the desert habitats experience the necessity to excrete the excess salts or ions in order to preserve the salt balance or the osmolality balance in blood. From this point, the purpose of salt glands is to control the reptiles’ daily metabolism and concentration of ions in the organism’s liquids in order to excrete the excess salts and to contribute to the effective organism’s functioning. The salt gland works as organs to preserve the salt balance with references to the possible minimal loss of water, and this organ is important to control the organism’s balance of sodium, potassium, and chloride and the necessary excretion of the excessive elements. It is significant to note that in spite of the fact that a lot of elements can be excreted with the help of the organism’s other organs, chloride is mainly excreted with the help of the salt gland.
The effective functioning of the salt gland can protect lizards such as Uromastyx aegyptius during the periods of droughts when the enough amount of water is unavailable for the lizards living in deserts. That is why, the role of the salt gland can be examined only with references to the specifics of the gland’s work. It is important to pay attention to the fact that the composition of the secreted fluids, secreting potassium chloride as well as sodium chloride which depend on the dietary ion content can be varied in relation to the salt gland functioning (Bradshaw et al., 1984; Kaslow, 2011). This specific ability to control the excretion of salts with the help of salt glands helps different desert animals regulate their metabolism processes by adjusting these processes to the extreme temperatures, lack of the herbivorous food, and water. The high salt food which is usually spread in deserts becomes a source of feeding for the lizards as the salt gland participates in the excess salts excretion without the significant water losses (Hazard, 2001; Minnich, 1968).
The specific thermoregulatory adjustments of the lizards can be discussed as behavioral or physiological changes of the organism to deflect the temperature changes from environmental heat loads (Firth & Belan, 1998). These adjustments are observed as the result of the blood osmolality which is the measure of the solute particles concentration in the blood which can be influenced by the ability of the organism to excrete the excess salts or other chemical elements. From this perspective, the appropriate functioning of the salt gland can guarantee that the blood osmolality is preserved at the level relevant for the healthy activities of the lizard’s organism.
The connection of the work of the salt gland and the blood osmolality rates was determined with the help of many researches and investigations. Thus, the biochemical analysis of the lizards’ plasma allows marking out the changes occurred in the reptiles’ blood in the high temperature environment. According to the research conducted by El-Banna and Al-Johany, “the main increase in plasma total proteins at the 45°C was due to an increase in albumin and α 1-globulin fractions” (El-Banna & Al-Johany, 2003, p. 3). Furthermore, the group of researchers pay attention to the fact that the “balance of water and ions is partly linked to excretion, the removal of metabolic wastes from the body”, as a result, the role of the salt gland in the organism of reptiles is accentuated (O’Driscoll et al., n.d.). It is possible to assume that any changes in the activities of the salt gland can lead to the ineffective excretion of the chemicals preserved in the organism’s liquids, and reptiles become to suffer from the salt imbalance, and they cannot adapt to the changes in temperature, the lack of the water or plants, and to the specific heat typical for the deserts’ environments (Arnold, 1986).
From this point, the main function of the salt gland in reptiles is the regulation of the salts concentration in plasma. The function of the salt gland does not depend on the place where it is located in the reptile’s organism. Thus, the salt glands of some reptiles can occupy the special shallow depressions near the reptile’s eyes. However, the salt gland does not play the major role in the maintenance of the vitality of reptiles under the conditions of environment heat loads. More attention should be paid to some other factors of survival which are the excretion of the sodium and potassium from cloaca as insoluble urate salts because they perform the additional role in preserving the chemical balance in the reptile’s organism (Dufour, 1993).
Following the idea that the salt gland is important for improving the reptiles’ abilities for survival under the drastic environmental conditions, it is necessary to pay attention to the ability to change the composition of the secreted fluid in relation to the reptiles’ needs as the additional advantage to provide lizards with the ability to become flexible regarding the changes in their diets, availability of water, and the rates of salt or other chemicals in plants and water. The additional flexibility is necessary for improving the adaptation functions of the reptiles’ organisms. Furthermore, the salt glands are important to intensify the specific osmoregulation functions of the organism (Babonis & Brischoux, 2012). Excreting simple ions and the minimal amount of water, the salt gland controls the stability of the organism in relation to the salt balance and its adaptation abilities.
In order to summarize all the above-mentioned information, it should be said that Uromastyx aegyptius possesses the special organs necessary to regulate the ability of its organism to adjust to the extreme natural conditions typical for deserts. Due to the fact that the lizard inhabits the droughty areas of Arabia, its body is capable to survive at the extremely high temperatures and the lack of water. The salt gland locating above the eyes of the animal contributes to the lizard organism adjustment to the desert conditions by means of regulation of the salts concentration in blood and the excretion of the excess salts from the organism. Thus, the specific survival ability of reptiles and lizards in particular depends significantly on the functioning of their salt glands.
References
Arnold, E. N. (1986). A key and annotated checklist to the lizards and amphisbaenians of Arabia. Fauna of Saudi Arabia, 8(1), 335-435.
Bradshaw, S., Lemire, M., Vernet, R., & Grenot, A. (1984). Aldosterone and the Control of Secretion by the Nasal Salt Gland of the North African Desert Lizard, Uromastix acanthinurus. General and Comparative Endocrinology, 54(1), 314-323.
Babonis, L., & Brischoux, F. (2012). Perspectives on the Convergent Evolution of Tetrapod Salt Glands. Integrative and Comparative Biology, 8(5), 1–12.
Dufour, R. D. (1993). Osmometry. The rational basis for use of an underappreciated diagnostic tool. Web.
El-Banna, A. A., & Al-Johany, A. M. (2003). Effect of Cold and Hot Temperature on Behavioral and Selected Physiological Measures of Uromastyx aegyptius (Agamidae). Science and Technology, 8(1), 1-10.
Firth, B. T., & Belan, I. (1998). Daily and seasonal rhythms in selected body temperature in the Australian lizard Tiliqua rugosa (Scincidae): Field and laboratory observations. Physiological Zoology, 71(1), 303-311.
Hazard, L. (2001). Ion secretion by salt glands of desert iguanas (Dipsosaurus dorsalis). Physiological and Biochemical Zoology, 74(1), 22-31.
Kaslow, J. E. (2011). Serum Proteins. Web.
Minnich, J.E. (1968). Maintenance of water and electrolytic balance by desert iguana, Dipsosaurus dorsalis. American Zoologist , 8(1), 782.
O’Driscoll, K.J., Staniels, L.K., & Facey, D.E. (n.d.). Osmoregulation and excretion. Web.