Cutaneous Respiration

Adaptations for cutaneous respiration include intraepidermal claret vessels in cryptobranchid salamanders (hellbenders and giant salamanders) (Supplemental Fig. e7) and development of elaborate pare folds that increase surface area for gas exchange (eastward.g., the Lake Titicaca Frog).

From: Pathology of Wild animals and Zoo Animals , 2018

AIR-BREATHING FISHES | Respiratory Adaptations for Air-Breathing Fishes

J.B. Graham , in Encyclopedia of Fish Physiology, 2011

Pare

Cutaneous respiration is documented for nigh of the major fish groups and only a few differences distinguish the air-animate species ( encounter besides GAS Exchange | Respiration: An Introduction). Many developing fishes breathe exclusively through their skin prior to gill development. Larval Monopterus respire through extensive subepithelial capillary networks. Posthatch Neoceratodus accept a ciliated respiratory epithelium covering their body surface.

Fish peel is a less effective gas-exchange organ than either the gills or ABO because of its greater thickness, the added diffusion barriers of scales and mucus, and low perfusion and ventilation potentials. Among species shown to have cutaneous respiration, water–blood improvidence distances range from fifty to 400   μm, and there is no consistent human relationship betwixt features such every bit scales, epidermal thickness, or amount of vascularization, and the charge per unit of cutaneous Oii transfer. For example, a cutaneous V ˙ O 2 of 32% of total V ˙ O 2 was measured for the heavily scaled Erpetoichthys calabaricus. Fish peel is metabolically active; the epidermis contains a living epithelium besides as sensory and secretory cells, all of which receive diet via dermal capillaries. Cutaneous respiration may serve the skin but not deeper aerobic requirements. Such a function would, however, be limited in hypoxic or stagnant water, which minimizes diffusion.

Specializations for skin respiration in amphibious air-breathing fishes include the presence of epidermal capillaries (reduce air–blood diffusion distance) along the dorsal torso surface (this area is readily exposed to air and makes less contact with the substrate). In mudskippers, which obtain virtually one-half of their O2 via the skin, air–blood diffusion distances can be less than 5   μm along the dorsal-body surface but as much equally 150–200   μm at other sites. In Kryptolebias (= Rivulus) marmoratus, which is totally reliant on skin respiration in air, capillaries on its dorsal body surface are within 1   μm of the body surface. Amid aquatic air breathers, the most dramatic application of cutaneous respiration occurs in the eleotrid, Dormitator latifrons. In hypoxic water, this fish hyperinflates its physoclistous gas bladder and becomes positively buoyant, thus emerging its forehead to expose a dumbo capillary network that is engorged with claret and functions for aeriform respiration ( Effigy 13 ).

Figure 13. Overhead view of a large number of Dormitator latifrons aggregated at a dam in Panama. Each fish is positively buoyant and has its aerial-respiratory frontal peel patch exposed to air.

 Reproduced from Fig. 2.9 in Graham JB (1997) Air Animate Fishes: Evolution, Diversity and Adaptation. San Diego, CA: Academic Press, with permission from Elsevier.

Read full affiliate

URL:

https://www.sciencedirect.com/science/article/pii/B9780123745538000459

Water Balance and Gas Exchange

Laurie J. Vitt , Janalee P. Caldwell , in Herpetology (Fourth Edition), 2013

Pare

The highly permeable skin of amphibians is a major site of gas substitution in terrestrial, semiaquatic, and aquatic species. Cutaneous respiration accounts for some gas exchange in certain species of reptiles ( Fig. 6.twenty). Substitution of respiratory gases occurs past diffusion and is facilitated by a relatively thin layer of keratin and a rich supply of capillaries in the pare. Exchange of gases across the skin in water is limited by the same concrete factors every bit substitution across other respiratory surfaces.

Effigy half-dozen.xx. Cutaneous exchange of gases in amphibians and reptiles. Orange bars signal uptake of oxygen; green bars indicate excretion of carbon dioxide. Values represent the percent of total gas exchange occurring through the skin.

 Adapted from Kardong, 2006.

Ventilation of skin, equally with gills and other respiratory surfaces, is required to disrupt the boundary layer that tin can develop. Xenopus has been observed to remain submerged longer and to move less frequently in moving compared to still water. Most plethodontid salamanders have neither lungs nor gills and are largely terrestrial (Fig. 6.21). The majority of their gas exchange occurs through the pare. In these salamanders, in contrast to others, there is no partial separation of the oxygenated and venous blood in the middle. Many species of this diverse group, considering of their style of respiration, are limited to cool, oxygenated habitats and to nonvigorous activity. Their oxygen uptake is merely ane-third that of frogs nether similar conditions. Plethodontids that inhabit tropical habitats where temperatures can exist loftier, such as Bolitoglossa in tropical rainforests, are active primarily on rainy nights. Waterproof frogs cede their ability to undergo cutaneous respiration in exchange for the skin resistance to water loss.

Effigy 6.21. Plethodontid salamanders, like this Plethodon angusticlavius, have no lungs. All respiration occurs across other pare surfaces. Consequently, all live in wet or moist habitats, most are secretive and/or nocturnal, and most are small in body size (L. J. Vitt).

Some amphibians increment their capacity for cutaneous respiration by having capillaries that penetrate into the epidermal layer of skin. This modification is carried to an extreme in Trichobatrachus robustus, the "hairy frog," which has dense epidermal projections on its thighs and flanks. These projections increment the surface area for gaseous exchange. Hellbenders, Cryptobranchus alleganiensis, alive in mountain streams in the eastern United States. These big salamanders take extensive highly vascularized folds of skin on the sides of the torso, through which 90% of oxygen uptake and 97% of carbon dioxide release occurs. Lungs are used for buoyancy rather than gas commutation. The Titicaca frog, Telmatobius culeus, which inhabits deep waters in the high-elevation Lake Titicaca in the southern Andes, has reduced lungs and does non surface from the depths of the lake to breathe. The highly vascularized skin hangs in neat folds from its body and legs (Fig. 6.22). If the oxygen content is very low, the frog ventilates its skin by bobbing. Other genera of frogs, salamanders, and caecilians (typhlonectines) have epidermal capillaries that facilitate gas exchange.

Figure half dozen.22. The Titicaca frog Telmatobius culeus (Ceratophryidae) lives at bully depths in Lake Titicaca and does not surface to breathe. The large folds of skin greatly increase the surface area of the pare, facilitating cutaneous respiration (V. H. Hutchison).

Gas exchange in tadpoles occurs across the peel to some degree in all species. Polliwog peel is highly permeable, similar to that of adults. Gas substitution across the peel is prevalent in bufonids and some torrent-dwelling species that do not develop lungs until metamorphosis. Microhylids, some leptodactylids, and some pipids have reduced gills, thus increasing their reliance on cutaneous respiration.

Recent studies show that some reptiles, once thought non to exchange gases through the peel, may apply cutaneous respiration for as much as twenty–thirty% of total gas exchange. In some aquatic species, such every bit Acrochordus and Sternotherus, gas exchange beyond the pare is especially meaning for carbon dioxide (Fig. vi.20). Even in terrestrial taxa such equally Lacerta and Boa, measurable amounts of gas exchange occur cutaneously. A sea serpent, Pelamis platurus, frequently dives and remains submerged. During these dives, oxygen uptake equals 33% of the total, and 94% of the carbon dioxide loss is through the skin. Substitution does not occur through scales but rather through the skin at the interscalar spaces.

Read full affiliate

URL:

https://www.sciencedirect.com/science/article/pii/B978012386919700006X

Operant Learning in Invertebrates

Romuald Nargeot , Laura Puygrenier , in Reference Module in Life Sciences, 2019

two.iii.ane Adaptation of breathing behavior

The fresh water snail Lymnaea stagnalis is a bi-modal breather in that it tin exhale directly through the skin (cutaneous respiration), or through the pneumostome, a respiratory orifice that conveys air into a lung (aerial respiration) ( Lukowiak et al., 2006). To perform aeriform respiration, the snail moves to the water surface and when the pneumostome is in contact with the temper, it opens fully. Then, the mantle muscles contract and expel gas from the lung. Subsequent musculus relaxation allows passive re-inflation of the lung. This bicycle of expiration/inspiration is repeated several times earlier the pneumostome closes again, signaling the stop of an aerial respiratory bout. The animal emits several successive bouts of aeriform respiration earlier submerging. In eumoxic conditions, information technology essentially performs cutaneous respiration and expresses simply 1–two aerial respirations per hour. All the same, this behavior can be motivated by hypoxic water weather. In these conditions, which are not harmful to the snail, the expression of aerial respiration strongly increases. This motivated behavior is hands observable and quantifiable in terms of pneumostome openings (i.e., number of breaths) and total fourth dimension the pneumostome is open (i.e., duration of jiff). Moreover, the essential neurons for generating pneumostome opening and endmost accept been identified, allowing this system to help uncover causal neuronal and molecular processes of operant conditioning, memory germination and their regulation by factors such as forgetting and stress.

In an operant workout procedure in a hypoxic Nii–rich environment, each spontaneous endeavour at pneumostome opening was associated with delivery of a punisher; a tactile stimulation applied with a wooden applicator to the pneumostome (Lukowiak et al., 1996, 2003). This aversive stimulus triggers pneumostome closure. Repeated associations between this operant and the punisher reduce both the number of aeriform breaths and the full animate fourth dimension. Yoked-control animals that receive the tactile stimulus independently of their own beliefs, just in temporal correlation with animate in a trained snail, practise not alter their respiratory behavior. This training protocol is composed of one or two successive sessions of 30 or 45 min. Memory of the penalty is tested by comparing the number of pneumostome opening at different periods after the concluding training session. The behavioral changes were found to be consolidated into intermediate- (lasting 2–three h) and long-term (lasting up to 6 h after preparation) memories depending on the number of, or interval between, the training sessions. A more elementary procedure, based on a single training trial, too forms long-term retention. In this paradigm, as before long as the animal opens its pneumostome, information technology is placed for 30 s into a watch glass containing a punisher composed of a high concentration of potassium chloride. The brute is then transferred into a eumoxic aquarium. Yoked-control animals allow testing the contribution of this operant/punisher association. These animals are placed in the high potassium chloride solution regardless of their behavior. Additional control animals are prepare into like glass-watches but containing fresh-water. None of these 2 control groups expressed a change in their aerial respiratory behavior.

Read full chapter

URL:

https://world wide web.sciencedirect.com/science/article/pii/B978012809633890788X

Learning Theory and Behaviour

D. Eisenhardt , Due north. Stollhoff , in Learning and Retentiveness: A Comprehensive Reference, 2008

1.27.two.two.i Lymnaea stagnalis: The operant aeriform respiration paradigm

Lymnaea stagnalis is an aquatic pulmonate snail ( Effigy 5 ). It is a bimodal sabbatical and tin can exhale via its skin (cutaneous respiration) or through a elementary lung (aerial respiration). When the creature stays in brackish h2o where the oxygen content is low, information technology becomes hypoxic. Then the snail comes to the water surface for aerial respiration. Information technology opens and closes its respiratory orifice, the pneumostome, and breathes through the lung ( Figure 6(a) ). This behavior by the snail is used in the operant aerial respiration paradigm (Lukowiak et al., 1996). Here the snails are put in beakers of water, which is made hypoxic by bubbling North2 through it. When the animal attempts to open its pneumostome as a reaction to the hypoxic water, it receives a gentle tactile stimulus to the pneumostome area, reducing its aerial respiration, without affecting cutaneous respiration. The number of openings is recorded during preparation periods and retention tests. Learning takes place if the number of attempted pneumostome openings is significantly decreased betwixt the first and the last training trial. It is of import to note that in this paradigm memory retrieval and retentiveness tests consist of the aforementioned procedure as the grooming sessions. They are only designated differently for the reader's convenience.

Effigy v. The snail Lymnaea stagnalis The snail Lymnaea stagnalis sinks from the water surface to the ground of the pond. Photograph by Kathrin Spöcker.

Figure half dozen. The snail Lymnaea stagnalis: Neuronal network underlying respiratory beliefs. (a) Lymnaea stagnalis with opened pneumostome (arrow). From Lukowiak Thousand, Sangha S, Scheibenstock A, et al. (2003) A molluscan model arrangement in the search for the engram. J. Physiol. 69–76. (b) Schematic drawing of the key design generator (CPG). A chemosensory stimulus (here hypoxia) activates sensory neurons (SNs) in the pneumostome area, which in turn provide excitatory input (green line) to the right pedal dorsal 1 interneuron (RPeD1). Once stimulated, RPeD1 activates the input3 interneuron (IP3) via a biphasic effect (inhibition followed by excitation) (blueish line) and inhibits visceral dorsal 4 interneuron (VD4) (crimson line). IP3 in turn excites both RPeD1 and the I/J motor neurons involved in pneumostome openings (O). IP3 also produces an inhibitory effect on VD4, and after release from this inhibition, VD4 fires, resulting in pneumostome closure (C). Tactile stimulation of the pneumostome area evokes closure of the pneumostome, and the aerial respiratory behavior stops. Adapted from Figure ane in Sangha S, Varshney North, Fras M, et al. (2004) Memory, reconsolidation and extinction in Lymnaea require the soma of RPeD1. Adv. Exp. Med. Biol. 551: 311–318. Syed NI Winlow Due west (1991) Coordination of locomotor and cardiorespiratory networks of Lymnaea stagnalis by a pair of identified interneurones. J. Exp. Biol. 158: 37–62.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780123705099000905

Biology and Diseases of Amphibians

Dorcas P. O'Rourke DVM, MS, DACLAM , Matthew D. Rosenbaum DVM, MS, DACLAM , in Laboratory Brute Medicine (Tertiary Edition), 2015

3 Respiratory Organization

Larval amphibians breathe primarily through gills. Adult amphibians may retain and use gills, lose gills and develop lungs, exhale with both gills and lungs, or have neither and utlize cutaneous respiration mechansims. X. laevis tadpoles and axolotls take both gills and lungs and will gulp air at the water's surface. Axolotls flex their external gills to movement fresh water over the filaments; this behavior increases when animals are housed in warm water with decreased oxygen content (Gresens, 2004). Developed plethodontids (lungless salamanders) lack both lungs and gills, and rely on cutaneous respiration. Skin, in fact, is the chief respiratory surface in most amphibians and must be kept moist. In species that apply lungs for respiration, air is forced in and out of the lungs past movement of the buccopharyngeal flooring (Zug, 1993). Lungs lack alveoli and are very frail and easily ruptured (Wright, 1996) (Fig. 18.5). In many frog species, the trachea is short, and bifurcation occurs close to the glottis; this anatomic feature must exist taken into account when performing endotracheal intubation.

Figure xviii.v. Amphibian lungs lack alveoli and are very fragile.

Read full chapter

URL:

https://world wide web.sciencedirect.com/science/article/pii/B9780124095274000183

Caudata (Urodela)

Eric J. Baitchman , Timothy A. Herman , in Fowler's Zoo and Wild Brute Medicine, Book viii, 2015

Special Physiology

Mechanisms of respiratory commutation in Amphibia are remarkable for the taxa as a whole and may occur via four routes: branchial, buccopharyngeal, cutaneous, or pulmonary. The Caudata are unique in the extent to which different families accept adapted to unlike primary routes. Branchial respiration is present in all amphibians as larvae, whereas only some neotenic salamander species retain this means of respiration as a primary route through adulthood. Cutaneous respiration is too employed past all amphibians to various degrees, although to a greater extent in caudates than in anurans. In anurans, cutaneous respiration occurs primarily as a ways of carbon dioxide exchange, with the bulk of oxygen exchange occurring in the lungs. 21,31 Most caudates, by comparison, accept up most of their oxygen through cutaneous respiration, even in species that possess lungs. 58 Respiratory capillaries are concentrated in the skin in taxa that rely on the cutaneous route every bit the primary site for gas exchange, as in the lungless Plethodontidae and aquatic Cryptobrachidae. The cryptobranchids likewise utilize modified skinfolds to increment surface area and vascularization to heighten respiratory exchange underwater. 31

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9781455773978000025

AMPHIBIANS

Natalie Mylniczenko , in Transmission of Exotic Pet Do, 2009

RESPIRATORY Organisation

There are iv forms of respiration in caudates, and they are species dependent: branchial, cutaneous, buccopharyngeal, and pulmonic. Animals with gills may have curt or long filaments depending on their natural environment. Animals with short gills are typically located in stream areas and thus accept higher requirements for dissolved oxygen. Cutaneous respiration can occur in these animals because of a loftier surface area on the skin and a low metabolic charge per unit; additionally, anaerobic glycolysis tin occur. Behavioral responses, such every bit rocking, allow a electric current to run beyond the skin, optimizing contact with dissolved oxygen in the water. Near salamanders possess ii lungs, with either single lobes (aquatic) or sacculated lobes (terrestrial). There is a lungless salamander. Costal grooves (peel folds forth the ribs) also increase the integumentary surface area. Buccopharyngeal respiration technically is cutaneous respiration occurring within the oral crenel. The trachea of caudates is very brusk and should prompt the clinician to practise caution when performing procedures like intubation and tracheal washes.

Read full chapter

URL:

https://www.sciencedirect.com/science/commodity/pii/B9781416001195500081

Biology and Diseases of Amphibians

Dorcas P. O'Rourke , Terry Wayne Schultz , in Laboratory Animal Medicine (Second Edition), 2002

3. Respiratory System

Larval amphibians breathe primarily through gills. Adults tin retain and use gills, lose gills and develop lungs, breathe with both gills and lungs, or accept neither (Fig. 8 ). Adult plethodontids (lungless salamanders) lack both lungs and gills, and rely on cutaneous respiration. Skin, in fact, is the primary respiratory surface in near amphibians and must be kept moist. In species that use lungs for respiration, air is forced in and out of the lungs by motion of the buccopharyngeal flooring ( Zug, 1993). Lungs lack alveoli and are very fragile and hands ruptured (Wright, 1996). In many frog species, the trachea is short, and bifurcation occurs shut to the glottis; this anatomic characteristic must exist taken into account when performing endotracheal intubation.

Fig. 8. Axolotls are large, aquatic, neotenous salamanders that respire through feathery external gills.

Read full chapter

URL:

https://world wide web.sciencedirect.com/science/article/pii/B978012263951750020X

Anesthesia and Analgesia in Amphibians

Dorcas P. O'Rourke , Audrey L. Jenkins , in Anesthesia and Analgesia in Laboratory Animals (Second Edition), 2008

Two. GENERAL CONSIDERATIONS

Amphibians are poikilothermic and therefore rely on external heat sources to generate adequate body temperatures for metabolic processes. Like reptiles, each amphibian species has a preferred temperature range. There is, however, considerable variation among species, and amphibians can be found in a broad variety of temperate and tropical habitats (Tabular array 20-1). Preferred temperature ranges for a given species should be obtained if at all possible. If this data is unavailable, temperate frogs can exist kept at approximately xx–25°C and tropical frogs at 25–30°C (Raphael, 1993). Many salamander species live under leaf litter in cool environments, or in cool water streams in mountainous regions. These temperate species prefer ranges of 10–xvi°C (Jaeger, 1992). Tropical salamanders may be kept at 15–twenty°C (Raphael, 1993).

Table 20-ane. Full general TEMPERATURE RANGES

Temperate Tropical
Frog/toad a 20–25°C 25–thirty°C
(68–77°F) (77–86°F)
Salamander a,b ten–16°C 15–xx°C
(50–lx.8°F) (59–68°F)
a
Raphael, B.L. (1993). Amphibians. Vet. Clin. Due north Am. Small Anim. Pract. 23, 1271–1286.
b
Jaeger, R.G. (1992). Housing, treatment and nutrition of salamanders. In "The Intendance and Utilize of Amphibians, Reptiles and Fish in Research." (D.O. Schaeffer, Thou.M. Kleinow, and L. Krulisch, eds.), pp 25–29. S.C.A.Due west.

Amphibian respiratory anatomy is equally variable as temperature preference. Most amphibians begin life as aquatic larvae, with gills as the primary organ for oxygen exchange. Some larvae (for instance, Xenopus tadpoles and Ambystoma tigrinum larvae) have lungs also as gills, and swim to the water'south surface to gulp air (Fig. xx-1 ). Many salamander larvae also utilize cutaneous respiration for a pregnant portion of oxygen exchange. Adult frogs have paired lungs; in some species, cartilage reinforces the lungs. Adult salamanders may have lungs, gills, both lungs and gills, or neither ( Fig. xx-2). One group of salamanders, the plethodontid salamanders, lack lungs and breathe solely through cutaneous respiration. The buccopharyn-geal cavity is highly vascular and is besides used for respiration. In species that exhale through lungs, inspiration begins past wrinkle of throat muscles, which depress the floor of the buccal cavity. This has the effect of pulling air through the nostrils and filling buccal cavity with air. Consequently, closure of the nostrils, opening of the glottis, and elevation of the buccal crenel flooring and then force air into the lungs. To remove air from the lungs, the buccal floor is depressed while the nares are closed and the glottis is open. And then the nares are opened, the glottis is closed, and the buccal floor is elevated to force air out of the mouth (Duellman and Trueb, 1986). The trachea of most amphibians is extremely short, and caution must be taken if intubation is attempted (Wright, 2001). Both low oxygen and elevated carbon dioxide levels stimulate respiration in about amphibians (Van Vliet and West, 1992). High oxygen levels inhibit respiratory movements in amphibians.

Fig. 20-1. In addition to breathing through gills, Xenopus tadpoles volition gulp air at the h2o's surface.

Fig. 20-two. The axolotl is a salamander that breathes through feathery external gills.

Amphibian skin is highly glandular. In that location are two basic types of skin glands: mucous and granular. Mucous glands are numerous and establish over the unabridged body surface. They secrete a slimy fungus, which serves to keep pare moist and facilitate cutaneous respiration (Fig. twenty-3). Mucus also protects the skin from abrasive trauma and inhibits pathogen entry. Granular glands are less abundant than mucous glands, and may be scattered over the body or clustered. The parotoid glands of toads, which announced as raised areas behind the eyes, are examples of amassed granular glands. Parotoid glands secrete cardiotoxins designed to deter predators. Other toxins secreted by granular glands include hallucinogens and neurotoxins. Different types of granular glands can secrete a variety of substances, including pheromones and antimicrobial compounds (Clarke, 1997).

Fig. 20-3. Mucous glands encompass the entire torso of the amphibian.

While hematologic and serum biochemical data are limited, Table 20-two provides values for a few of the more common species used in research.

TABLE xx-2. HEMATOLOGIC AND SERUM BIOCHEMICAL VALUES

Measurements African clawed frog (Xenopus laevis) a Bullfrog (Rana catesbeiana) b Leopard Frog (Rana pipiens) c Japanese Newt (Cynops pyrrhogaster) d Axolotl (Ambystoma mexicanum) e
Hematology
PCV (%) − 30.ane (25–39) 24.6(31–39.ix) xl.0(38.i–41.nine) −
Hgb (g/dl) fourteen.86 half dozen.8 (5.12–xi.06) 26.75 (2.iv–nine.half dozen) − −
WBC (103/μl) 8.two xx.5 (11.half-dozen–32.7) − − −
Neutro/heter (%) 8.0 (6.9–9.1) threescore.ix (xl.0–86.one) 26.5 (11–48) 28.0 (26.4–30.6) sixty.9 (57.3–64.5)
Lymphocytes (%) 65.3 (62.6–68.0) 26.8 (16.3–39.8) 53.4 (29–75) 3.0 (two.half-dozen–3.4) 26.4 (24.half dozen–28.2)
Monocytes (%) 0.5 2.9 (1.0–5.0) 11.0 (5–24) half-dozen.0 (5.0–7.0) −
Eosinophils (%) − 5.8 (2.0–11.ix) 7.3 (four–xi) four.0 (3.3–4.seven) 6.i (iv.2–8.0)
Basophils (%) 8.5 (7.one–9.ix) three.5 (0.6.0) 4.4 (0.9) 57.0 (iii.8–sixty.2) 0.1 (0.0–0.two)
− −
Chemistries
Sodium (mEq/L) − 118.6 (99–144) − − −
Potassium (mEq/L) − iii.62 (1.92–5.84) − − −
Chloride (mEq/L) − 108.6 (1.0–116) − − −
Albumin (g/dl) − 1.58 (1.02–2.67) − − −
Calcium (mg/dl) − eight.31 (vi.0–xi.2) − − −
Creatinine (mg/dl) − 4.83 (1.07–12.3) − − −
AST (IU/L) − 48.one (23–80) − − −
ALT (IU/50) − 12.4 (7–20) − − −
LDH (IU/Fifty) − 117 (50–260) − − −
Phosphorus (mg/dl) − 8.83 (4.1–thirteen.seven) − − −
Magnesium (mEq/L) − 2.41 (one.33–four.09) − − −
Uric acrid (mg/dl) − thirteen.4 (i.3–30.2) − − −
Urea (mg/dl) − 84.2 (thirty.1–180) − − −
Glucose (k/Fifty) − 0.v (0.1–0.98) − − −
a
Carpenter, J.Due west. (2005). Exotic animal formulary, ed 3, WB Saunders, St Louis.
b
Coppo, J.A., Mussart, N.B., and Fioranelli, A. (2005). Claret and urine physiological values in subcontract-cultured Rana catesbeiana (Anura: Ranidae) In Argentina. Rev. Biol. Trop. (Int. J. Trop. Biol) 53(3–iv), 545.
c
Rouf, M. A. Hematology of the leopard frog, rana pipiens. Copeia, Vol. 1969, No. 4. (Dec. v, 1969), pp. 682–687.
d
Pfeiffer, C.J. Pyle, H. and Asashima, Grand. (1990). Blood prison cell morphology and counts in the Japanese newt (Cynops pyrrhogaster). J Zoo Wild animals Med. 21(1), 56–64.
e
Ussing, A.P. and Rosenkilde, P. (1995). Consequence of Induced Metamorphosis on the Immune System of the Axolotl, Ambystoma mexicanum General and Comparative Endocrinology 97(3), 308–319.

Read total chapter

URL:

https://www.sciencedirect.com/scientific discipline/article/pii/B9780123738981500243

Tetrapod Relationships and Evolutionary Systematics

Laurie J. Vitt , Janalee P. Caldwell , in Herpetology (Quaternary Edition), 2014

Modern Amphibians—The Lissamphibia

Nigh recent analyses indicate that modern amphibians (Lissamphibia) are monophyletic (i.e., share a common antecedent). Numerous patterns of relationship have been proposed, but the recent discovery of Gerobatrachus hottoni from the Permian and a reanalysis of existing data betoken that frogs and salamanders had a common ancestor about 290   Ma. Gerobatrachus is a salamander-similar amphibian with a skull and other features of the head that are similar to those of frogs. Thus caecilians, which are much older, are sister to the frog–salamander clade. The Lower Triassic frog, Triadobatrachus massinoti, from Madagascar, shows a possible link to the dissorophid temnospondyls. T. massinoti shares with them a large lacuna in the squamosal bone that may have housed a tympanum. Neither salamanders nor caecilians have tympana, although they have greatly reduced middle ears, suggesting contained loss of the outer ear structures.

A number of other unique traits debate strongly for the monophyly of the Lissamphibia. All share a reliance on cutaneous respiration, a pair of sensory papillae in the inner ear, two sound transmission channels in the inner ear, specialized visual cells in the retina, pedicellate teeth, the presence of two types of skin glands, and several other unique traits.

Three structures, gills, lungs, and peel, serve equally respiratory surfaces in lissamphibians; two of them oft function simultaneously. Aquatic amphibians, peculiarly larvae, utilize gills; terrestrial forms use lungs. In both air and water, the skin plays a major role in transfer of oxygen and carbon dioxide. One group of terrestrial amphibians, the plethodontid salamanders, has lost lungs, and some aquatic taxa also accept lost lungs or accept greatly reduced ones; these amphibians rely entirely on cutaneous respiration. All lunged species use a force–pump mechanism for moving air in and out of the lungs. 2 types of skin glands are nowadays in all living amphibians: mucous and granular (poison) glands. Mucous glands continuously secrete mucopolysaccharides, which keep the peel surface moist for cutaneous respiration. Although structure of the poison glands is identical in all amphibians, the toxicity of the diverse secretions produced is highly variable, ranging from barely irritating to lethal to predators.

The auditory system of amphibians has one channel that is common to all tetrapods, the stapes–basilar papilla channel. The other channel, the opercular–amphibian papilla, allows the reception of low-frequency sounds (<1000   Hz). The possession of two types of receptors may not seem peculiar for frogs considering they are vocal animals. For the largely mute salamanders, a dual hearing system seems peculiar and redundant. Salamanders and frogs have dark-green rods in the retina; these structures are presumably absent in the degenerate-eyed caecilians. Green rods are institute only in amphibians, and their particular function remains unknown.

The teeth of modern amphibians are ii-part structures: an elongate base of operations (pedicel) is anchored in the jawbone and a crown protrudes in a higher place the gum. Each tooth is normally constricted where the crown attaches to the pedicel. As the crowns wearable down, they break gratis at the constriction and are replaced by a new crown emerging from within the pedicel. Few living amphibians lack pedicellate teeth. Among extinct "amphibians," pedicellate teeth occur in only a few dissorophids.

Living amphibians share other unique traits. All have fatty bodies that develop from the germinal ridge of the embryo and retain an association with the gonads in adults. Frogs and salamanders are the only vertebrates able to raise and lower their eyes. The bony orbit of all amphibians opens into the roof of the mouth. A special muscle stretched across this opening elevates the eye. The ribs of amphibians do not encircle the body.

Read full affiliate

URL:

https://www.sciencedirect.com/science/article/pii/B9780123869197000010