. Chordate anatomy. Chordata; Anatomy, Comparative. 396 CHORDATE ANATOMY with the dendrites of a sensory nerve may become encapsuled by con- nective tissue to form a Meissner's corpuscle. Free nerve terminations occur in the skin of all classes of chordates, usually in the form of multiple arborizations These may lie in the epidermis or in the corium, in either case being located where they may respond to changes in pressure. Such free nerve terminations in the skin are found in all classes of vertebrates, and are believed to be CLUB-SHAPED TACTILE CORP (KRAUSE) ENCAPSULED NERVE-
. Chordate anatomy. Chordata; Anatomy, Comparative. 396 CHORDATE ANATOMY with the dendrites of a sensory nerve may become encapsuled by con- nective tissue to form a Meissner's corpuscle. Free nerve terminations occur in the skin of all classes of chordates, usually in the form of multiple arborizations These may lie in the epidermis or in the corium, in either case being located where they may respond to changes in pressure. Such free nerve terminations in the skin are found in all classes of vertebrates, and are believed to be CLUB-SHAPED TACTILE CORP (KRAUSE) ENCAPSULED NERVE- KNOT- (GOLGI-MAZZONI)'. <;?^r^5— EPI DERM IS FREE NERVE- ENDING IN EPIDERMIS FREE NERVE- ENCAPSULED GROUP OF TACTILE CELLS (MEISSNER) DIAGRAMS CUTANEOUS SENSE ORGANS IN CRANIOTES WITH SEODNDARY SENSE CELLS. Fig. 349.—Varieties of cutaneous sense organs in chordates. A, B, C show sensory terminations in the skin of Acrania. B' to D' show varieties of terminations in craniotes. C to C* and D' to Z?'* respectively represent stages in the hypothetical evolution of encapsuled nerve terminations. (Redrawn after Plate.) the sensory mechanism of painful sensations arising in the skin. The sense of touch apparently depends chiefly upon the tactile cells or cor- puscles in the corium, of which various forms occur. Meissner's corpuscles, present only in primates, are located in the corium papillae of the palms and soles, and in the external genital organs. Each corpuscle consists of a group of tactile cells surrounded by a rela- tively thin envelope of connective tissue and connected with one or more nerve fibers. The non-medullated nerve fiber twists spirally among the tactile cells, each of which is in contact with a reticular nerve termination. In birds and reptiles nerve endings are connected with tactile cells of Merkel but without a connective-tissue capsule. These tactile cells. Please note that these images are extracted from scanned page images that may have been di
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Keywords: ., bookcentury1900, bookpublisherphi, booksubjectanatomycomparative
