THE BLOOD OF CHICK EMBRYOS:
QUANTITATIVE EMBRYOLOGY
AT A CELLULAR LEVEL
LEO LEMEZ
Department of Anatomy, Charles University, Prague, Czechoslovakia
I. Introduction
197
II. Qualitative and Quantitative Data on Chick Embryo Blood Corpuscles
throughout the Incubation Period
198
A. Erythrocytes
199
B. Thrombocytes
212
C. Leucocytes
214
D. Other Formed Elements in the Chick Embryo Blood
220
E. Total Blood Volume and Related Values throughout the Incubation
Period
221
F. Mitoses in Circulating Blood Cells and their Role in Primitive Erythrocyte
Proliferation
223
G. Life Span of Chick Embryo Erythrocytes
228
H. Balance Sheet of Erythrocyte Production and Destruction throughout the
Incubation Period
232
III. Autodifferentiation of Embryonic Blood-forming Tissues
236
A. Autodifferentiation in vitro
236
B. Self-differentiation in the Yolk Sac Wall without Circulation (Anidian)
238
References
239
I. Introduction
Up to ten years ago, quantitative studies at the cellular level in adult
vertebrates were not numerous, apart from investigations of cells of the
body fluids and of the blood-forming organs. In the last decade such
investigations have been extended to cells of many tissues and organs
showing replacement of worn out elements or renewal in the adult (e.g.,
Leblond and Walker, 1956; Price, 1958; Stohlman, 1959). In most
instances in the adult the number of newly formed cells equals that of
cell deaths, so that a steady state or dynamic equilibrium in the total
cell number results and only the renewal rate has to be considered.
In developing organisms, in which such studies are still rare, cell
production has to cover not only the absolute increase in cell number in
a growing organ or in a part of the embryonic body, but at the same time
the replacement of cells that emigrate, are shed, degenerate, etc. The
final goal of these studies is a better understanding of the dynamics of
the embryonic cell population, to strike a balance which would demonG2
197
QUANTITATIVE EMBRYOLOGY
AT A CELLULAR LEVEL
LEO LEMEZ
Department of Anatomy, Charles University, Prague, Czechoslovakia
I. Introduction
197
II. Qualitative and Quantitative Data on Chick Embryo Blood Corpuscles
throughout the Incubation Period
198
A. Erythrocytes
199
B. Thrombocytes
212
C. Leucocytes
214
D. Other Formed Elements in the Chick Embryo Blood
220
E. Total Blood Volume and Related Values throughout the Incubation
Period
221
F. Mitoses in Circulating Blood Cells and their Role in Primitive Erythrocyte
Proliferation
223
G. Life Span of Chick Embryo Erythrocytes
228
H. Balance Sheet of Erythrocyte Production and Destruction throughout the
Incubation Period
232
III. Autodifferentiation of Embryonic Blood-forming Tissues
236
A. Autodifferentiation in vitro
236
B. Self-differentiation in the Yolk Sac Wall without Circulation (Anidian)
238
References
239
I. Introduction
Up to ten years ago, quantitative studies at the cellular level in adult
vertebrates were not numerous, apart from investigations of cells of the
body fluids and of the blood-forming organs. In the last decade such
investigations have been extended to cells of many tissues and organs
showing replacement of worn out elements or renewal in the adult (e.g.,
Leblond and Walker, 1956; Price, 1958; Stohlman, 1959). In most
instances in the adult the number of newly formed cells equals that of
cell deaths, so that a steady state or dynamic equilibrium in the total
cell number results and only the renewal rate has to be considered.
In developing organisms, in which such studies are still rare, cell
production has to cover not only the absolute increase in cell number in
a growing organ or in a part of the embryonic body, but at the same time
the replacement of cells that emigrate, are shed, degenerate, etc. The
final goal of these studies is a better understanding of the dynamics of
the embryonic cell population, to strike a balance which would demonG2
197