31.19
Baarmoederbuizen
De baarmoeder of eileiders fungeren als de doorgang waardoor oöcyten van de eierstokken naar de baarmoeder reizen. Elke eileider is ongeveer 10 tot 13…
The uterine or fallopian tubes are 10 to 13-cm long passageways on either side of the uterus.
Each tube is divided into the infundibulum, ampulla, and isthmus.
The infundibulum is a funnel-shaped opening adorned with finger-like projections called fimbriae extending into the peritoneal cavity.
Next is the ampulla, the widest region that makes up more than half the length of the uterine tube.
The isthmus is the narrowest part connecting the uterine tube to the uterus.
Around ovulation, the fimbriae of the uterine tubes cover the ovaries and sweep their surface.
Inside the tube, cilia from the mucosal epithelium generate currents in the peritoneal fluid, aiding in oocyte capture.
Nonciliated secretory and peg cells in the epithelium release a fluid that nourishes the oocyte.
Smooth muscle layers around the mucosa contract peristaltically, complementing the cilia's work by moving the oocyte through the ampulla.
Typically, sperm fertilizes the oocyte in the ampulla before it travels via the isthmus to the uterus.
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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.