Blood islands are structures in the developing embryo which lead to many different parts of the circulatory system.
They primarily derive from plexuses formed from angioblasts. Within them, vacuoles appear through liquefaction of the central part of the syncytium into plasma. The lumen of the blood vessels thus formed is probably intracellular. The flattened cells at the periphery form the endothelium.
The nucleated red blood corpuscles develop either from small masses of the original angioblast left attached to the inner wall of the lumen or directly from the flat endothelial cells. In either case the syncytial mass thus formed projects from and is attached to the wall of the vessel. Such a mass is known as a blood island and hemoglobin gradually accumulates within it. Later the cells on the surface round up, giving the mass a mulberry-like appearance. Then the red blood cells break loose and are carried away in the plasma. Such free blood cells continue to divide.
Blood islands have been seen in the area vasculosa in the omphalomesenteric vein and arteries, and in the dorsal aorta.
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My friend, blood shaking my heart
The awful daring of a moment’s surrender
Which an age of prudence can never retract
By this, and this only, we have existed”
—T.S. (Thomas Stearns)
“For four hundred years the blacks of Haiti had yearned for peace. for three hundred years the island was spoken of as a paradise of riches and pleasures, but that was in reference to the whites to whom the spirit of the land gave welcome. Haiti has meant split blood and tears for blacks.”
—Zora Neale Hurston (1891–1960)