Kirkes' Handbook of physiology / revised and rewritten by Charles Wilson Greene.

  • Kirkes, William Senhouse, 1823-1864.
Date:
1910
Catalogue details

Licence: Public Domain Mark

Credit: Kirkes' Handbook of physiology / revised and rewritten by Charles Wilson Greene. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

    86/792 (page 62)
    less refractive more fluid material. The polarizing microscope reveals the fact that the middle piece which corresponds in position to the dark trans- verse band is doubly refractive, isotropic, while the surrounding material, the light band, is singly refractive, anisotro[)ic. In transverse section, figure 70, the area of the muscle substance is mapped out into small polygonal areas by a network of clear lines called Co/m- heim's areas. The lines represent the substance between the sarcostyles. This substance probably represents the less differentiated contractile sub- stance, called sarooplasm. In figure 81 the interfibrillar sarcoplasm is indicated by the longitudinal and transverse lines. Heart Muscle.—The muscle sub- stance of the heart is composed of Fig. 77. Fit>. -8. Fig. 77.—A Section of Cardiac Muscle, Diagrammatic. (From E. A. Schafer, after Heidenhain.) Fig. 78.—Intercellular Continuity of Muscle Fibrils in Cardiac Muscle. (From E. A. Schafer after Przewosky.) mononucleated masses of protoplasm, cardiac muscle cells, in which the substance of the cell presents the transversely striated appearance char- acteristic of the voluntary muscle just described. But the heart muscle is physiologically much more like an involuntary muscle. The cells are rather small, two to four times as long as thick, and the nucleus is usually situated near the middle of the cell, figure 79. There is no sarcolemma; on the other hand, the cells present branched and irregular outlines, but adjacent cells interlock in close-fitting contact. Certain observers have described fibrils as extending across the so-called cell boundary and noted that not all such boundaries enclose nuclei. These