Atlas and epitome of human histology and microscopic anatomy / by Johannes Sobotta ; edited, with extensive additions, by G. Carl Huber.

  • Sobotta Johannes, 1869-1945.
Date:
1903
Catalogue details

Licence: In copyright

Credit: Atlas and epitome of human histology and microscopic anatomy / by Johannes Sobotta ; edited, with extensive additions, by G. Carl Huber. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    tlie nuclear monihranc in the nieslies of the linln network is lilled with fluid, the nuclear sap. The centrosome, the third constituent of the cell, rej)resents the di/namic center of the cell in the pi’occsses of cell division. In the resting cell it a])pears as a single or as two ])unctiforni structures, which arc ])rohably gen- erally less than 1 p in diameter. Since the centrosome is so small aiul so didicidt to find, it has not yet been ]H)s- sible to demonstrate it in all the cells of the human body. We need not, however, on this account doubt its existence. In many animal cells (ova) centrosomes are often found of considerably greater size. The centrosome often lies in a small clear area of ])rotoplasm, now and then showing fine radiate lines. This structure often becomes prominent only at the time of cell division. PROLIFERATION OF CELLS. (fomj)lex ])rocesses affecting more ])aiiicularly the nucleus manifest themselves during the ])roliferation of cells. The division of the cell-body is without exception preceded by (lirision of the nncletis; the former may even fail to take jdace and the process then results in the formation of cells having several or many nuclei. iStructures which develop in this way and have numerous nuclei in a common protoplasm are known as syncitia ^ or plasmodia. Thus the trans- versely striated muscle-fiber is a syncitium. In normnl human tissues probably all cells divide by what is known as indirect cell division, karyokinesis, or mitosis, in conti’a- distinction to a less imjxn’tant type designated as direct or amitotic cell division. A number of phases or stages are usually distinguished in the complicated jn’oeess of mitosis. The first is the ' Miuiy autliors use the term syiioitium to denote a strueture aris- ing from the fusion of several eells, and idasmodium to denote forms arising; from tlie division of the nucleus without any subse(juent divi- sion of the cell.