Development of the liver in the chicken embryo. II. Erythropoietic and granulopoietic cells
Date
1993
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
John Wiley & Sons, Inc.
Abstract
Hepatic hemopoiesis is apparent in the chicken embryo on
day 7 of incubation (Hamburger and Hamilton Stage 301, and a peak in
hemopoietic activity occurs on day 14 (Stage 40). During this period, the
differentiation of hemopoietic cells was examined by light microscopy and
by transmission and scanning electron microscopy. Glycol methacrylate
sections were used in lieu of smears to study hemopoietic cells, thus minimizing
the problems of cell shrinkage and rupture. The sections were superior
to smears for close examination of nuclear and cytoplasmic morphologies
and for precise localization of hemopoietic cells to intravascular
and extravascular sites. The avian liver is involved directly with erythropoiesis
and granulopoiesis only. Erythropoietic cells, occurring in intravascular
and extravascular locations, appear throughout the time frame examined.
Blood islands with granulopoietic cells were not observed until
days 8-9 (Stage 35). Granulopoiesis in the liver produces only eosinophilic
leukocytes. Individual granulopoietic cells appear first in the connective
tissue sheaths of hepatic vessels, and these cells subsequently congregate
into blood islands. Endothelial cells of the sinusoidal linings, through asymmetric
divisions, frequently release daughter cells into the circulation, and
Kupffer cells are actively engaged in phagocytosis of erythrocytes. From a
comparative standpoint, the elements deemed critical to hemopoiesis in the
mammalian liver-prehepatocyte population, hepatic vasculature, and
compartments for stem cell differentiation-may not hold the same importance
in the bird, owing to an inordinate reliance on intravascular hemopoiesis
in this vertebrate class.
Key words: Capillaries, Chick embryo, Vascular endothelium, Hematopoiesis,
Kupffer cells, Liver, Microscopy, Morphogenesis
o 1993 Wiley-Liss, Inc.
Description
Copyright held by publisher
Keywords
Biology
Citation
Wong, G. K., Cavey, M. J. "Development of the liver in the chicken embryo. II. Erythropoietic and granulopoietic cells" Anatomical Record 1993 235: 131–143