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J Palin

Publications and source records attributed to J Palin.

8 recordsLinked to original sources
PubMed1972

Cochlear Structure in the Dolphin, Lagenorhynchus obliquidens.

The cochleas of five specimens of the Pacific white-sided dolphin, Lagenorhynchus obliquidens, that had been fixed by intravital perfusion, embedded in celloidin, and sectioned in a continuous series, were studied with particular attention to the numbers and distribution of hair cells and ganglion cells. The number of inner hair cells is estimated as 3272 and the number of outer hair cells is estimated as 12,899, for a total of 16,171 cells. The ganglion-cell population is estimated as 50,412 after correction for cell splitting in the sectioning process.

Journal Article↗
PubMed1971

The Cochlea of the Dolphin, Tursiops truncatus: General Morphology.

The anatomy of the cochlea of the dolphin Tursiops truncatus was studied in a number of specimens after fixation by vital perfusion, cellodin embedding, and serial sectioning. The results reveal the general structural relations and cellular detail up to the limits of light microscopy. A description is given of the variations of structure along the course of the cochlea, in which there are many departures from the typical mammalian form, especially in the compact quality of the tissues and the sturdiness of its elements. Apparently these features represent an adaptation of the cetacean ear to the reception of high-frequency sounds.

Journal Article↗
PubMed1971

Cochlea of the dolphin, Tursiops truncatus: the basilar membrane.

In the dolphin Tursiops truncatus, the basilar membrane over its course its course from basal to apical ends shows a systematic variation in width and in the manner and rigidity of its suspension. The suspension is by bony laminae on both the outer and inner edges in the basal region, and by progressively less rigid attachments in the more apical regions, until near the apex the membrane is held only by connective tissue. The basilar membrane shows an unusual variation in width of 14 times, ranging from an astonishingly small value of 25 mum at the basal end to a value toward the apex of about 350 mum. This structural variation is in harmony with the extension of sensitivity of the dolphin ear into the very high frequencies, and suggests unusual capabilities of pitch discrimination in this high range.

Animals↗
PubMed1971

The cochlea of the dolphin, Tursiops truncatus: hair cells and ganglion cells.

A study of the cochlear hair cells in Tursiops truncatus showed 3451 inner and 13,933 outer hair cells, for a total of 17,384. This total is of the same order of magnitude as the value of 14,975 for the human ear. Determination of the ganglion cell population for the dolphin gave a total of 95,004 cells, which is about three times as many as in man. The large number of hair cells in the dolphin ear suggests a high order of auditory proficiency in general, and especially a marked ability of tonal differentiation. The large ratio of ganglion cells to hair cells suggests unusual capabilities in the utilization of auditory information.

Animals↗
PubMed1969

Hearing in the giant sea turtle, Chelonia mydas.

Measurement were made of the cochlear potentials in three specimens of the giant sea turtle, Chelonia mydas, in response to both aerial and mechanical stimulation of the ear. The results show maximum sensitivity in the region of 300 to 400 Hz, with a rather rapid decline in sensitivity for lower and especially for higher tones. The upper limit for the observation of cochlear potentials without injury is 2000 Hz, and a practical limit of usefulness of this ear is probably about 1000 Hz.

Animals↗