There is a close correlation between the angioarchitecture of the human testis and its inner subdivision into testicular lobules. Serial sections from paraffin and epon-embedded testicular tissue were used to examine the angioarchitecture of the human testis, and computer-aided 3-D-reconstruction was used to demonstrate the correlation between blood vessels and tissue organization. The recurrent arteries arise from the centripetal arteries, and run in the central axis of the testicular lobule. At regular intervals of on average, 300 microns the segmental arteries arise from the recurrent artery, which supplies segments of the testicular parenchyma perpendicular to the long axis of the testicular lobules. Within such a segment, the segmental artery supplies the microvasculature, which is partly surrounded by Leydig cells and partly stands in close contact with the wall of the seminiferous tubules. The venous drainage occurs through the intralobular veins, which run to the periphery of the lobule (towards the septum). These veins lead into the septum and there they join the collecting veins. A lobule can have several segments depending on its size. The base of such a tissue segment is directed towards the septum whereas the top is directed towards the centre of the lobule. Sections of several seminiferous tubules can be found in such a segment. The flow of blood from the arterial to the venous side of the testicular circulation occurs radially from the centre of the lobule to the septum.

Arteries↗

PubMedDate not supplied

Microvasculature of the human testis in correlation to Leydig cells and seminiferous tubules.

The microvasculature of the human testis is closely related to the Leydig cells and the seminiferous tubules. Semi-thin sections of testicular tissue serve as a basis for the computer-aided 3-D reconstruction of the microvasculature, the seminiferous tubules and the Leydig cells. After vascular perfusion with glutaraldehyde (5.5%) and paraformaldehyde (4%), it is possible by means of light and electron microscopy, to analyse the organization of the capillaries between the Leydig cells (inter-Leydig cell capillaries) as well as of those within the lamina propria (intramural capillaries). These arise from arterioles, deriving from branches of the segmental arteries. The capillaries ramify between the Leydig cells and run either semi-circumferentially around the seminiferous tubules (peritubular capillaries) or penetrate the lamina propria of the neighbouring tubules. This is the beginning of the intramural capillary which after leaving the tubular wall continues to a further capillary path. Consequently, the microvasculature of the human testis with regard to the seminiferous tubules is subdivided into afferent, intramural and efferent capillaries. Leydig cell clusters are present on both the arterial and the venous sides of the microvasculature.

Capillaries↗

PubMedDate not supplied

Differences in microcirculatory bed arrangement in some skeletal muscles of the rat and golden hamster.

The architectural features of the most peripheral parts of the microcirculatory bed were studied in selected skeletal muscles (cremaster, retractor, spinotrapezius, and ventral stripe of spinotrapezius) in rats and golden hamsters ranging in weight between 130 and 330 and 130 and 180 g, respectively. In the cremaster muscle of both species, a very complicated, irregular and heterogenous arrangement of terminal arterioles, as well as of postcapillary and collecting venules was found. In the retractor, the most regular arrangement was along the margins of the middle part of muscle, but an irregular brush-like branching of the terminal arterioles and collecting venules limits the use of these areas. Similarly, in spinotrapezius muscle the most regular vascular architecture, complicated by a different fashion of terminal arterioles and collecting venules, was along the ventral border of muscle. The most regular and simplest vascular arrangement was in the ventral stripe of spinotrapezius of the rat. Therefore, this muscle is recommended as most appropriate for intravital experimental studies of the skeletal muscle microcirculatory bed in all age and weight groups.

Aging↗