31.19
Les trompes utérines
Les trompes utérines ou trompes de Fallope servent de conduit par lequel les ovocytes se déplacent des ovaires vers l'utérus. Chaque trompe de Fallope…
Les trompes utérines ou de Fallope sont des passages de 10 à 13 cm de long de chaque côté de l’utérus.
Chaque tube est divisé en infundibulum, ampoule et isthme.
L’infundibulum est une ouverture en forme d’entonnoir ornée de projections en forme de doigts appelées fimbriae qui s’étendent dans la cavité péritonéale.
Vient ensuite l’ampoule, la région la plus large qui représente plus de la moitié de la longueur de la trompe utérine.
L’isthme est la partie la plus étroite qui relie le tube utérin à l’utérus.
Autour de l’ovulation, les fimbriae des trompes utérines recouvrent les ovaires et balaient leur surface.
À l’intérieur du tube, les cils de l’épithélium de la muqueuse génèrent des courants dans le liquide péritonéal, ce qui facilite la capture des ovocytes.
Les cellules sécrétoires et peg non ciliées de l’épithélium libèrent un liquide qui nourrit l’ovocyte.
Les couches musculaires lisses autour de la muqueuse se contractent de manière péristaltique, complétant le travail des cils en déplaçant l'ovocyte à travers l'ampoule.
En règle générale, les spermatozoïdes fécondent l’ovocyte dans l’ampoule avant qu’il ne se déplace via l’isthme jusqu’à l’utérus.
View the full transcript and gain access to JoVE Core videos
Q1: What are the three main sections of the uterine tube?
The uterine tube is divided into three main sections: the infundibulum, a funnel-shaped opening with finger-like fimbriae; the ampulla, the widest region comprising more than half the tube's length; and the isthmus, the narrowest section connecting to the uterus. Each section plays a distinct role in oocyte transport and fertilization.
Q2: How do fimbriae help capture the oocyte during ovulation?
During ovulation, the fimbriae extend over the ovaries and sweep their surface to capture the released oocyte. These finger-like projections cover the ovary and guide the oocyte into the infundibulum, initiating its journey through the uterine tube toward the uterus.
Q3: Why is the ampulla the most common site of fertilization?
The ampulla is the widest section of the uterine tube and provides an optimal environment for sperm and oocyte to meet. Typically, sperm fertilizes the oocyte in the ampulla before it travels through the isthmus to the uterus, making this region ideal for successful fertilization.
Q4: What role do cilia play in moving the oocyte through the uterine tube?
Ciliated epithelial cells in the uterine tube lining generate currents in the peritoneal fluid that transport the oocyte toward the uterus. These cilia work alongside peristaltic contractions of smooth muscle layers to move the oocyte through the ampulla and toward the isthmus.
Q5: What do secretory and peg cells contribute to oocyte transport?
Nonciliated secretory and peg cells in the uterine tube epithelium release a nourishing fluid that sustains the oocyte during its journey. This fluid provides essential nutrients to the oocyte as it travels from the ampulla through the isthmus to the uterus.
Q6: How do smooth muscle contractions assist oocyte movement?
Smooth muscle layers surrounding the mucosa contract peristaltically, complementing the work of cilia by propelling the oocyte through the uterine tube. These coordinated muscular contractions work with ciliary currents to ensure efficient transport of the oocyte toward the uterus for implantation.
Q7: What happens to the oocyte after fertilization in the ampulla?
After sperm fertilizes the oocyte in the ampulla, the resulting zygote travels through the isthmus, the narrowest part of the uterine tube, before reaching the uterus for implantation a few days later. This journey allows the embryo to develop while traveling to its implantation site.