Life Sciences Commons^™

The Effects Of Adrenergic And Cholinergic Stimulation On Skin Gland Secretions In The Dwarf African Frog Hymenochirus Curtipes, Daniel H. Gong

University of the Pacific Theses and Dissertations

Many studies have been done on the neural control of serous gland secretion in the skin of frogs and newts. However, no studies have been published on the effects of adrenergic and cholinergic neurotransmitters on the sexually dimorphic breeding glands of male frogs. The present study examined the effects of neurotransmitters on the serous and breeding glands of Hymenochirus curtipes. Explants of dorsal skin and postaxial skin (containing whole breeding glands) were incubated in vitro with epinephrine, norepinephrine or acetylcholine for 30 minutes. The explants were then preserved and examined histologically for signs of secretion. The area and perimeter of …

Developmental Changes In Organ Systems Of Transforming Anuran Larvae, Muriel Humphrey Marshall

University of the Pacific Theses and Dissertations

Despite an enormous amount of information on the biochemical and physiological changes of amphibian metamorphosis, information about the general anatomy of anuran larvae is not readily available. The present study is a comparison of the general morphological changes during metamorphic climax of three anuran species belonging to three different families. This anatomical information is designed to assist those wishing to correlate cellular and chemical events with the corresponding morphological events.

Respiratory Quotient During Metamorphosis Of Hyla Regilla Tadpoles, James Frederic Welles

University of the Pacific Theses and Dissertations

Metamorphosis may be defined as postembryonic developmental changes in non-reproductive structures of an organism. Such changes anticipate changes in the organism's environment (Frieden, 1961). Metamorphosis of amphibian larvae is dependent on the thyroid hormone in the circulating body fluid, and the normal sequence of metamorphosis has been correlated with a progressive increase in the concentration of thyroxine in the blood (Barch, 1953; Moore, 1964).

While the rate of oxygen uptake in developing tadpoles has been well studied and documented, only a single reference on carbon dioxide release could be found. Belehradek and Huxley (1927) noted that carbon dioxide output increased …

The Effect Of Temperature On The Growth Rates Of Several California Frogs, Donald Avila Villeneuve

University of the Pacific Theses and Dissertations

To date the majority of the work on the ecological significance of embryonic temperature relationships has been with Eastern Frongs. The writer is aware of only two papers describing work of this nature with California frogs: Schechtmann and Oleson (1941) working with temperature tolerance in embryos of Hyla regilla, and the work of Zweifel (1955) on the Rana boylei species group.

For this reason it seemed desireable to study the effect of temperature on the growth rates of some frogs native to California and, since work of this nature has been done with the eastern Rana catesbeiana by Moore (1942b), …