Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    An experimental study on the isolated lateral semicircular canal of the bull frog (1986)
    Springer
    European archives of oto-rhino-laryngology and head & neck 243 (1986), S. 27-30 
    Details
    ISSN: 1434-4726
    Keywords: Bull frog ; Lateral semicircular canal ; Action potential ; Crista ; Time constant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We used isolated lateral semicircular canals from the bull frog, Rana catesbeiana. The cupula was removed from the crista and a glass micropipette was used to depress the sensory cilia on the crista toward the utricular side. Five points on the crista were selected for stimulation. Decremental time constants of the lateral ampullary nerve action potentials were measured. The longest time constant was obtained from stimulation to the wide portion of the crista. The time constant progressively decreased as the narrow side of the crista was approached. These results indicate that the lateral semicircular canal crista is equivalent to the halved posterior semicircular canal crista in terms of both morphology and physiology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00457903
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Characterization of a hemichordate fork head/HNF-3 gene expression (2000)
    Springer
    Development genes and evolution 210 (2000), S. 11-17 
    Details
    ISSN: 1432-041X
    Keywords: Key words Hemichordates ; Deuterostomes ; fork head/HNF-3 gene ; Vegetal plate cells ; Archenteron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Based on anatomical and developmental similarities, hemichordates are thought to be most closely related to chordates. However, so far very few developmental genes have been characterized from hemichordates. To gain molecular insight into the developmental mechanisms involved in the origin and evolution of chordates, we investigated the expression of a fork head/HNF-3 (PfHNF3) gene in the acorn worm embryo. Chordate fork head genes are implicated in the formation of endoderm, notochord and floor plate. We found that a PfHNF3 transcript was first detected at the early blastula stage; the signal of in situ hybridization was found in the vegetal plate cells, invaginating endoderm and then in the archenteron. By the late gastrula and into the early tornaria larva stages, an intense signal remained in the anterior region of the archenteron, while the expression in the other regions of archenteron decreased. The intense signal was retained in the pharynx of the tornaria larva. A comparison of the pattern of PfHNF3 with that of HNF-3 genes of sea urchin, ascidian, amphioxus and vertebrate suggests a possible acquisition of new functions of the gene during deuterostome evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00008181
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of carbonic anhydrase in the vestibular end organs of the guinea pig (1989)
    Springer
    European archives of oto-rhino-laryngology and head & neck 246 (1989), S. 56-60 
    Details
    ISSN: 1434-4726
    Keywords: Carbonic anhydrase ; Vestibular organ ; Guinea pig ; Histochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Carbonic anhydrase activity was demonstrated cytochemically on an ultrastructural level in the vestibular end organs of the guinea pig. Reaction product was found in the dark cells, transitional cells, cells of the planum semilunatum and supporting cells. In the dark cells, reaction product was observed in the cytoplasm as well as in the basal infoldings. Reaction product was also observed in the basal infoldings of the transitional cells and the cells of the planum semilunatum. The globular structures inside the supporting cells, transitional cells and the cells of the planum semilunatum were also surrounded by the reaction product. These findings suggest that carbonic anhydrase may have different functions, such as water and ion transport, respiration, nutrition and calcium carbonate deposition in the vestibular end organs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454136
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    An experimental study demonstrating the physiological polarity of the frog's utricle (1987)
    Springer
    European archives of oto-rhino-laryngology and head & neck 244 (1987), S. 215-217 
    Details
    ISSN: 1434-4726
    Keywords: Action potential ; Utricular nerve ; Striola ; Cupula ; Physiological polarity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The frog Rana nigromaculata was used as an experimental model. The utricle and its nerve were isolated with the anterior and the lateral semicircular canal ampullae in frog Ringer's solution. The utricular otoconia and the otoconial membrane were then carefully removed. The halved anterior canal cupula was next placed in the tip of a glass microelectrode, which was mounted on a micromanipulator. The cupula was placed in the center of either the medial or the lateral part of the macula and was moved toward or away from the striola along the axis vertical to the striola. When the medial part of the macula was stimulated, 5 μm of striolapetal cupular movement elicited an excitatory nerve discharge. When the lateral part of the macula was stimulated, the striolapetal stimulus likewise induced an excitatory response. These results indicate the existence of physiological polarity on the utricular macula.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455308
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...