Development of the hemomicrocirculatory bed of the human gonads during the prenatal period of ontogeny

: The formation of the organospecific hemomicrocirculatory bed of the ovaries and testes has been studied by a complex of light, transmissive and scanning electron microscopy in 3--9-month-old human fetuses. The change of the diffusive protocapillary bed is secured by: 1) reduction of some protocapillaries; 2) appearance of secondary capillaries from the growth buds of the preceeding microvessels; 3) formation of arteriolar and venular links of the hemomicrocirculatory bed from the protocapillaries at the expense of differentiation of the developing paravasal connective tissue into cellular elements of the muscular and adventitial tunics. The secondary blood capillaries of the human gonads are predominantly formed intraendothelially. During the prenatal ontogenesis presence of the secondary blood capillaries of somatic uninterrupted type is specific for the human gonads.