Textbook of anatomy. Section 2. The muscular system: the nervous system: the organs of sense and integument / By D.J.Cunningham,Robert Howden and A.M.Patterson.

  • Cunningham, D. J.
Date:
1906
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Licence: In copyright

Credit: Textbook of anatomy. Section 2. The muscular system: the nervous system: the organs of sense and integument / By D.J.Cunningham,Robert Howden and A.M.Patterson. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    Recessns labyrinth] the ductus endolymphaticus, and thus the utricle and saccule are only indirectly connected by a Y-shaped tube. Another constriction makes its appearance between the saccule and the ductus cochlearis near its commencement, and forms the canalis reuniens of Hensen. The epithelial lining is at first columnar, but becomes cubical throughout the whole labyrinth, except opposite the terminations of the auditory nerve, where it forms the columnar epi- thelium of the maculae of the utricle and saccule, of the cristee ampullse, and of the organ of Corti. On the floor of the ductus cochlearis two ridges appear, of which the inner forms the limbus laminge spiralis, whilst the cells of the outer become modified to form the rods of Corti, the hair cells, and the supporting cells of Deiters'and Hensen. The mesoderm surrounding the otic vesicle is differentiated into : (1) a fibrous layer, the wall of the membranous labyrinth ; (2) a cartilaginous external capsule, the future petrous bone ; and (3) an is ultimately absorbed to form the peri- Coclilear part Saccule 600. Left labyrinth of a liumaii embryo of about four weeks ; B, Left Labyrinth of a human embryo of about five weeks (from W. His, jun.) intervening layer of gelatinous tissue, which lymphatic space between the bony and membranous labyrinths. OKGANS OF TASTE. The peripheral organs of the sense of taste (organon gustus) consist of groups of modified epithelial cells, termed the taste buds, which are found on certain parts of the tongue and its immediate neighbourhood. Taste buds are present in large numbers around the circumference of the papillae vallatse, while some are also found on their opposing walls (Fig. 601). They 1- 3 A B Fig. 601. A, Section through a papilla vallata of human tongue. B, Section through a part of the papilla foliata of a rabbit. 1. Papilla. 2. Vallum 3. Taste buds. 4. Papillte. 5. Taste buds. 6. Duct of serous gland. are very numerous over the fimbri^B linguae, which correspond with the papillae foliatse of the tongue of the rabbit, and are also found over the posterior part and sides of the tongue, either on the papillae fungiformes or throughout the stratified epithelium. They exist, also, on the buccal surface of the soft palate and on the posterior aspect of the epiglottis.