Oviduct
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- Uterine tubes or fallopian tubes are paired, convoluted tubes which has the unique function of conveying the eggs and sperms in opposite direction.
- It connects the ovary to the uterus
Four functional divisions of the oviduct
Fimbriae
- Ovarian end of the oviduct with fringed edges
- Forms ovarian bursa with mesosalpinx
- Ovarin bursa open in all farm animals
- Completely covers the ovary in the pig
- Ovarian bursa covers only ovulation fossa in the mare
- Fimbriae move freely
Infundibulum
- Funnels shaped second portion
- Size varies with age and size of the animal
- Has the abdominal opening of the oviduct – ostium abdominale
Ampulla
- Forms more than half the length of the oviduct
- Connects infundibulum to isthmus
Isthmus
- Connected to uterus at the utero-tubal junction
Musculature of the oviduct
- Outer longitudinal and inner circular smooth muscles
- Thickness increases from ovarian to uterine end
- Contraction of longitudinal muscles shorten the oviduct
- Contraction of circular muscles cause annular constrictions
- Exhibits three types of contractions
- Localized peristalsis
- Segmental contractions
- Worm like writhing contraction
- These contractions occur simultaneously or in specific patterns
- Pattern and amplitude of contractions also varies in different parts
- Most vigorous contractions occur at ovulation
Mucosa of the oviduct
- Exhibits primary, secondary and tertiary folds
- Thrown into high folds in ampulla
- Height decreases in isthmus
- Become low ridges at the utero-tubal junction
- Completely fill the lumen of the oviduct at the ovarian end
- Has one layer of ciliated and non-ciliated columnar cells
- Proportion of ciliated to non cilaited cells varies along the oviduct
- Related to the functions of different segments of the oviduct
- Dependent on ovarian estrogens for their function
- Ciliated cells are maximum at the fimbria – help pick up of the ovum
- Non ciliated secretory cells are maximum ampulla onwards
- Promote interaction of gametes and noursihment of the embryo
- Direction of oviducal fluids is towardssthe ovary
- Most of the oviducal secretions are lost into peritoneal cavity for 2-3d after estrus
- Subsequently fluids move down into uterus carrying the embryo
- Cilia beat at their maximum at ovulation
- Cilia usually beat towards the uterus
Functions of the oviduct
- Pick up of the ovum
- Fimbriae pick up the ovulated egg from the ovarian surface
- Capable of picking up of ovum from the contralateral side
- Oviducal secretions provide
- For Capacitation of sperm
- Conducive environment for fertilization
- Nutrition to young embryo
- Protection to oocyte, sperm and young embryo from attack by maternal immune system
- For cleavage of young embryo by secretion of clevage inducing protein
- Ciliary movements, muscular contractions and fluid flow help in
- Mixing of oviducal contents that improves encounter of the gametes
- Denudation of follicular cells from the ovum
- Transport of zygote into uterus
- Prevention of tubal implantation
- Oviduct transports egg and sperm in opposite direction at about the same time but never fails
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Last modified: Saturday, 7 January 2012, 5:53 AM