Development and descent of the testis.

Abstract

Normal testicular descent is achieved by a residuum of primitive embryonic mesenchyme which is retained through into the fetal period; this is the gubernaculum testis. It forms a medium into which the cremaster muscles and the processus vaginalis can develop in anticipation of testicular descent. At the time of descent the gubernacular mesenchyme dilates, largely due to the uptake of fluid by the interstitial hyaluronic acid. By this means the scrotal sac is dilated and, with concurrent growth of related structures, all under the overall influence of maternal and chorionic gonadotrophic (luteinising) hormones, stimulating the testicular interstitial cells of the fetal testis, testicular descent is permitted.