Contractions of the seminiferous tubules propel immobile immature sperm
Travelling 5 millimetres in one minute sounds slow. But if you’re a human sperm, it’s pretty speedy. While mature sperm can whizz about, immature sperm are immobile. So how do they move through the tubes in the testicles (seminiferous tubules) where they’re made? Researchers investigated in mice using live cell imaging of the tubules to measure the flow of fluid through them. They found the flow matched the contractions of muscle-like cells in the tubule walls, pictured here (red) in a 3D reconstruction of mouse testes compiled using fluorescence confocal microscopy. Contractions were detected by fluorescently tagging and imaging calcium levels in these cells, which rise when they contract. It’s these coordinated contractions that propel the immature sperm through the tubules. This builds a clearer picture of how immobile sperm get moving.
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.