Egg transport

 

The egg after fertilization in the ampulla must traverse the oviduct to reach the uterus. In marsupial this takes only one day or less than 24 hours. Transportation in marsupial oviduct is rapid. In true mammals transportation varies. In man it takes about 2 days for the egg to reach the uterus after traversing the whole of the oviduct. The egg after spends more time in the ampulla than in the isthmus so that human is a chronic ampullary transport mammal while the rat for example is a chronic isthmic egg transport animal.

Control of egg transport

Egg transport is controlled by two mechanisms

  • Muscular activity
  • Ciliary action
  • Combination of muscular and ciliary action to propel the egg acrss the oviduct

Muscular transport: Muscular activity is aided by intrinsic myogenic contractility which is also aided by neurogenic factors. Myogenic contractility is supposedly independent of nervous stimulation. Hence it has been observed that the denervation of the oviduct does not completely abolish egg transport and even muscular activity. Experiments to completely denervate the reproductive tract have met with limited success since nerve supply to most parts of the female reproductive tract are from diverse origins and are mixed with parasympathetic and sympathetic components being different to separate.

Ciliary transport:  Distal of the oviduct has cilia and this region contains the largest luminal size in rat oviduct. The cilia is thought to maintain a chemical bond with the peripheral parts of the transproted egg and the cumulus cells. Ciliary transport is very important before the egg reaches the ampullaryisthmic junction. It is probable that ciliary transport is aided by endocrine factors wich may be produced locally and which may involve paracrine stimulation.

There is a combination of muscular/ciliary transportation. This may lead to chage in position of the oviduct during transportation so that this change may aid ovum pick up and also transportation across the ampullaryisthmic junction, all assisted by ciliary activity. It has been shown that peristaltic waves increases in the rabbit as estrus is approached.


Fallopian tube explanatory video



Ovulation and early cleavage video    

 

  
Egg transport:
Egg is released into the distal part of the tube and it initially journeys into the ampulla where fertilization takes place. The resulting embryo then journeys very slowly to reach the uterus for implantation.


Sperm transport: Oviduct is responsible for egg sperm and embryo transports. Its sperm transport has two phases. The fast and the slow one. The fast phase allows the sperm to reach the ampulla or even peritoneum in seconds. The second and slow phase takes several minutes.

 

 

 

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