In modern organisms the structure and arrangement of bone apatite crystals is dependent on the arrangement of the organic collagen fibers. This is reflected in the formation of different types of bone tissue, such as woven (immature) or lamellar (mature), in pathological versus normal bone, or fast-growing (woven) versus slow-growing (lamellar) tissue. Because the basic physiological processes of fracture healing are similar in extant vertebrates, similar patterns may exist in fossil taxa. The three questions of interest for this study were the following: 1) Do differences exist in modern bone apatite crystallinity between normal and pathologic bone? 2) Are differences between normal and pathologic tissue consistent in both modern and fossil bone? 3) Does the type of bone tissue affect fossilization? In this study, we use histological and x-ray diffraction (XRD) analyses to examine fracture pathologies in pedal phalanges from the theropod dinosaur Allosaurus fragilis, and two modern bird species, Branta canadensis (Canada goose) and Cathartes aura (turkey vulture). Raman spectroscopy analysis was performed on modern birds, but not fossil material. Stable isotope and rare earth elements (REE) analyses were performed on fossil material to determine if there are differences in how pathologic bone fossilizes compared to normal bone. Results from Raman spectroscopy and XRD confirm that pathologic bone is more crystalline than normal bone in both fossil and modern taxa. Stable isotope and REE analyses do not show any difference in fossilization between pathologic and normal bone, suggesting that these techniques are more suitable for examining taphonomic rather than physiological differences. / Geology

Call number: LD2668 .T4 1979 H37 / Master of Science

Call number: LD2668 .T4 1984 F46 / Master of Science

The Postcentral gyrus of the brain of the cat has been studied with the technics of Nisel and Golgi. Qualitative data concerning packing densities and volumes of the nerve cells and of the glia, as welll as the distribution of the dendrites are reported. The existence of alternate dendritic and axonal layers has been demonstrated and the relationship of these layers to the stripes of Baillarger has been analyzed. / fr

D.Sc. / Please refer to full text to view abstract

A histological investigation was carried out on the esophagus and stomach of the following birds: kingfisher (Megacercyle alcyon caurina), California murre (Uria aalgae Californioa), screeoh owl (Otus asio kennicotti),Peale's faloon (Falco peregrinius pealei), and sparrow hawk (Falco sparverius sparverius). A number of stains was used to intensify the different structures present. In the kingfisher, murre and owl the esophagus was a thin walled highly expansible tube of generally even calibre, whereas in the Peak's falcon the anterior part was dilated into a sac. The wall of the esophagus possessed the usual structure characteristic of this region of the digestive tube. Three types of glands have been distinguished in these birds. In the kingfisher and owl simple oval glands were situated almost entirely within the epithelium. The glands and excretory duct were composed of similar cells with slight variations occuring in excretory duct lengths. In the California murre the glands were still simple but had sunken to the tunica propria with just the excretory ducts passing through the epithelium. The gland cells were narrower, and the duct cells resembled those observed in the owl and the kingfisher. These glands were all apocrine secretory. However, in the Peale’s falcon and sparrow hawk secretion was holocrine. These glands were deeply embedded within the tunica propria and resembled the esophageal glands of the chicken. The excretory ducts were lined by squamous epithial cells. Although the birds examined possessed a variety of food habits: fish, mammals, birds and crustaceans, the food was essentially meat. However, considerable variations in the structure of the esophagus were observed. The proventriculus was comprised of: a mucosa, indented with minute gastric pits, a muscularis externa of three layers of smooth muscle, and a lamina adventitia that surrounded the entire tube. Within the mucosa the deep glands were situated. These were composed of large lobes, enveloped in a dense capsule of connective tissue and internally consisted of simple tubules that radiated about a central excretory duct. The structure of the proventriculus was more or less uniform in the birds investigated, with only slight variations occuring in cellular arrangement and cellular size. The gizzards in the birds examined were large spherical structures that filled a majority of the abdominal cavity. In the kingfisher, owl, Peale's falcon, and sparrow hawk, the gizzard was lined by a thin keratinoid lining that was secreted by the glands present in the gizzard mucosa. The muscularis externa was of approximately equal thickness throughout. In the murre, the keratinoid layer was five or six times as thick as in the above birds and the muscles showed a heavy development on the dorsal and ventral sides. This development took place toward a grinding mechanism that was necessary for processing the hard shelled crustaceans eaten by this bird. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

It was hypothesized that there may be microanatomic specializations in the urogenital slit and mammary region of cetaceans. There may be an integumentary-linked mechanism in these animals similar to that which causes the milk let-down response in terrestrial mammals. This hypothesis was tested on tissue samples from fourteen animals collected in a standardized array of fourteen samples from the urogenital area, and one each from the ventral aspect of the flipper and the mid-dorsal body wall for comparison. Using standard histological and ultrastructural procedures, including both transmission and scanning electron microscopy, tissues from nine species were investigated. These included the bottlenose dolphin (Tursiops truncatus), striped dolphin (Stenella coeruleoalba), harbor porpoise (Phocoena phocoena), pygmy sperm whale (Kogia breviceps), short and long finned pilot whales (Globicephala macrorhynchus and malaena respectively), beluga whale (Delphinapterus leucas), humpback whale (Megaptera novaeangliae), and fin whale (Balaenoptera physalus). Measurements were taken of the height of the epidermis, the thickness of the epidermal stratum externum, and the height and number of dermal papillae. Co1lagen bundles of the reticular dermis were measured and ranked by diameter. Nervous structures were quantitatively evaluated by type and location. No differences were found in the epithelial, connective, or nervous tissue of the skin in this region that would imply an increased sensitivity in this area. However, an observed unique organization of the connective tissue may imply a functional difference in the skin of the urogenital region unrelated to the milk let-down phenomenon. Possible alternative mechanisms for the initiation of milk let-down in cetaceans are discussed, including myoepithelial cell contraction caused by urogenital bumping by calves, vocalization by calvest and tacto/acoustic stimulation of the urogenital area by the calf. Epidermal thickness and papillary height varied among animals of different cetacean species, although there seemed to be a structural 'formula' applicable to the skin of all cetaceans that would permit efficient turnover of the epidermis. The significance of integumentary lipids is discussed. Deviations in cellular and subcellular structures of cetacean skin from those described in previous reports are mentioned, and a previously undescribed location for nerves in dermal papillae was revealed. / Master of Science

Call number: LD2668 .T4 1978 S25 / Master of Science

Call number: LD2668 .T4 1965 L334 / Master of Science