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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Marine mammal science 8 (1992), S. 0 
    ISSN: 1748-7692
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Observations were made on 11 brains from bowhead whales subsistence-harvested by Alaskan Eskimos under International Whaling Commission guidelines. This study is part of a larger project to determine the basic morphology of this endangered species. The bowhead brain is similar to other cetacean brains, particularly that of the southern right whale. Long olfactory peduncles are reflected upon the rostrodorsal surface of the cerebral hemispheres. Olfactory bulbs have not been recovered but are presumed to exist since nerve fibers have been identified histologically in the olfactory peduncles. The induseum griseum is evident on the corpus callosum. The hippocampus proper is small but protrudes into the lateral ventricle. The cruciate sulcus runs diagonally across the rostral surface, limiting a small frontal lobe. The structure of the floor of the sylvian fissure varies from a few short gyri radiating toward the circular sulcus to a more extensive and complex two-tiered arrangement including numerous gyri perpendicular to the gyrus bordering the paleocortex. Pineal-body-like tissue was present in one specimen. There is no interthalamic adhesion. The lateral geniculate body is elevated but smaller than the large medial geniculate body. The neurohypophysis was adherent on most brain specimens received.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 208 (1984), S. 481-490 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The macroanatomy of renicules and surrounding tissues from the kidneys of five Eskimo-harvested bowhead whales, Balaena mysticetus, was examined. These renicules are similar in overall structure to those of other cetaceans and intermediate in size. There are several important differences including the presence of arcuate vessels within the sporta perimedularis, the extension of connective tissue from the sporta deep into the peripheral cortex, and the presence of very large, thin-walled veins that occupy the interrenicular spaces. Arterial and venous plexuses outside the substance of the sporta reported in other cetaceans were not observed in the bowhead.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In the bowhead whale, Balaena mysticetus, the mucosa of the major airways from the blowholes through the rostral portion of the larynx is lined with parakeratotic, pigmented, stratified squamous epithelium. Scattered enlarged connective tissue papillae of the lamina propria of the nasal vestibules and the palatopharyngeal sphincter contain encapsulated nerve endings. Abundant papillae in the mucosa covering the epiglottic and arytenoid cartilages contain similar nerve endings. The remainder of the laryngeal cavity and laryngeal sac is lined by a variably pigmented, stratified squamous epithelium, which is not keratinized. At the laryngotracheal junction the lining changes to ciliated pseudostratified columnar epithelium which continues through the trachea and principal bronchi. Scanning electron microscopy (SEM) indicates that this epithelium is typically mammalian, with approximately half of the surface cells bearing cilia and slender microvilli. The remaining cells are mucus producing and have thicker microvilli. The valvular mass regulating the external nares consists of irregular, dense white fibrous connective tissue with numerous adipose cells and is penetrated by skeletal muscle cords ranging from 2-4 mm in diameter. The septal mass between the blowholes is composed of irregular, dense white fibrous connective tissue containing large tendinous bundles, clusters of adipose cells, and several large arteries and thick-walled veins. The lamina propria of the nasal vestibules is irregular, dense white fibrous connective tissue. That of the larynx is not as dense and contains proportionately more elastic fibers. The laryngeal sac does not contain elastic laminae, but does have a tunica muscularis of skeletal muscle bundles. Within the trachea and principal bronchi, the lamina propria possesses laminae of longitudinally oriented elastic fibers and simple, branched tubuloalveolar mucous glands. The nasal, laryngeal, tracheal, and bronchial cartilages are hyaline with vascular channels.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Components of the respiratory system from seven bowhead whales have been examined. The paired and laterally curved external nares are passively closed by a valve-like mass located in the rostral, lateral, and ventral walls of the nasal vestibules. Nasal septal cartilages are paired smooth plates rostrally changing to accordion-like folds caudally. The epiglottic and arytenoidal protuberances of the larynx are typically cetacean, but blunt. The cricoid cartilage is not a complete ring, but an elongated, inverted, troughshaped structure. The thyroid cartilage is trough-shaped with elongated cranial cornua curving dorsocaudally from each thyroid lamina. A conical mass of skeletal muscle serves as the floor of the short trachea and also surrounds the termination of the laryngeal sac. The trachea is dorsoventrally compressed, lacks a tracheal bronchus, and its width equals its length. The principal bronchi give rise to lobar bronchi at obtuse angles. Large segmental bronchi branch extensively from lobar bronchi near the mediastinal lung surface. The lungs are rectangular and of nearly uniform thickness throughout, without external or internal lobulation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Skin samples from most body regions of the bowhead whale were examined. The epidermis is 2.7 to 50 times thicker than that reported in other cetaceans with both regional and individual variations in thickness. The thinnest areas examined (1 mm) occur on the eyelid margins and the thickest (25 mm) occur on the lower jaw. A distinctive parakeratotic stratuim corneum with a thick underlying stratum spinosum (without a stratum granulosum) extgends over the entire body surface. From a few dozen to several hundred epidermal lesions are present on all whales studied. A typical stratum basale of germinative keratinocytes (with melanocytes in pigmented areas) rests upon a well-defined basal lamina. Epidermal rod arrays arise from the basal keratinocytes which cover highly elongated dermal papillae and extend to the epidermal surface through the distal stratum spinosum and the stratum corneum. At least four diatom genera occur on and in the stratum corneum and lesion areas of different whales. The superficial dermis consists of a papillary layer with long (up to 13 mm) dermal papillae interdigitating with the epidermis from a basal area that is 2-4 mm in thickness. The number of dermal papillae per mm2 varies inversely with the thickness of the epidermis. Large diameter, sensory papillae packed with tortuous, highly elongated, encapsulated nerve end organs also interdigitate with the thin epidermal areas of the ventral surface of the rostrum, the upper and lower lip margins, and the upper and lower eyelid margins. Scattered, single, stiff hairs emerge from the skin only in specific, pigmented regions of the head.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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