Elements of histology / by E. Klein.

  • Edward Emanuel Klein
Date:
1884
Catalogue details

Licence: Public Domain Mark

Credit: Elements of histology / by E. Klein. Source: Wellcome Collection.

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    of a very small amount of fibrous tissue as a matrix, I and in it are embedded numerous blood-vessels and cells. The few afferent arterioles break up into a dense net v/ork of capillaries, and these are continued as plexuses of veins, characterised by their size and exceedingly ♦ thin walls. The cells are of the same size, aspect, and shape as the osteoblasts of the osteogenetic tissue, and they are called marrow cells. In origin and structure, the tissue of the osteo- genetic layer of the i:>eriosteum and the marrow are i identical. In the embryo, the marrow is derived [from an ingrowth of the osteogenetic layer of the [periosteum (see below), and also in the adult the two tissues remain directly continuous. As will be shown later, the marrow at the growing ends of the bones is concerned in the new formation of osseous substance in the same way as the osteogenetic layer of the peri- osteum is in that of the surface; and in both tissues ibhe highly vascular condition and the cells (osteoblasts iof the osteogenetic layer, and marrow cells of the Imarrow) are the important elements in this bone jEormation. Marrow is of two kinds, according to ibhe condition of the cells. If many or most of these [ire transformed into fat cells, it has a yellowish aspect, ;md is called yellow marrow ; if few or none of them I'lave undergone this change, it looks red, and is called Yed marrow. In the central, or -marrow, cavity of the ?haft of tubular bodies, and in the spaces of some spongy bones, the marrow is yellow; at the ends of the shaft, in the spongy bone substance in general, and in 70ung growing bones, it is red. The cells, especially those of red marrow, are the dements from which normally vast numbers of red 3lood-corpuscles are formed, as has been mentioned on I former page. In marrow, particularly in red marrow, we meet \dth huge multi-nucleated cells, called Myeloplaxes of
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