Spermatozoa in the reproductive tract

1. Spermatozoa in the
Reproductive Tract
Technical Company for Industry and Trade
C.E.O
Eng. Mohammad AlSaleh
info@technicaljo.com

2. OUTLINE
-Introduction.
-Objective.
-Site of semen deposition.
-Sperm Survival and transport
-Interaction between sperm and female tract.
-Conclusions.

3. INTRODUCTION
Transport of sperm from site of deposition in the female
to site of fertilization represents a critical phase of the
reproductive process of farm animals. Sperm transport
failures, which result in fertilization failure, account for a
significant proportion of the loss of potential offspring in
each major class of animal.
Improving sperm transport and reducing fertilization
failure could reduce intercalving intervals of cattle and
increase lambing rate of sheep.

4. OBJECTIVE
Highlight about spermatozoa in the reproductive tract.

5. SITE OF SEMEN DEPOSITION
During mating, the bull deposits several billion
spermatozoa into the anterior vagina.
However, since the cervix is a major obstacle for sperm
transport, the number of spermatozoa finally reaching
the uterine body usually does not exceed 1%. In
artificial insemination, semen is generally deposited
directly into the uterine body, by-passing the cervix
and permitting the use of a considerably reduced
number of sperm.

6. ❖ Cervical versus Uterine Body Insemination.
❖ Bicornual versus Unicornual Insemination.
❖ Right versus Left Deep Unicornual Insemination

7. SPERM SURVIVAL AND TRANSPORT
In most species, fertilization occurs in the uterine tube next
to the ovary; during natural copulation, spermatozoa are
developed in the vagina (most species) or uterus via the
cervix (mare, sow, and botch). Even though ejaculated
spermatozoa are motile, the major factor in the transport
of spermatozoa to the site of fertilization is muscular
activity of the tubular genitalia following insemination.
The time required for spermatozoa to travel to the site of
fertilization in a cow is about 2.5 minutes, but the first
arriving spermatozoa typically do not accomplish
fertilization.

8. Based on calculated speed of bull spermatozoa, it
would take 1.5 hours for them to swim this distance. Less
than 0.5% of the ejaculated spermatozoa reach the
site of fertilization. Oxytocin, a peptide hormone from
the neurohypophysis, promotes muscular activity of the
female tubular genitalia to assist with spermatozoa
transport.
It is released in the cow during natural mating and
during artificial insemination, presumably as a result of
a natural reflex initiated by physical stimulation of the
female tract.

9. Under normal conditions, viability and survival times of
spermatozoa in the female reproductive tract are only
a matter of hours. Length of fertility in the female tract
is as follows: ewe, 30 to 48 hours; cow, 28 to 50 hours;
mare, 140 to 145 hours. The limited variability of
spermatozoa means that insemination must occur within
hours of ovulation so that viable spermatozoa are
present when ova arrive for fertilization. In most
species, female sexual receptivity begins some hours
prior to ovulation, so that this is possible.

10. Physiochemical and immunologic factors in the vagina
and cervix at the time of insemination play an
important role in sperm survival and transport into the
uterus and oviduct. The vaginal secretions immobilize
sperm within 1 to 2 hours of insemination the rapid
elimination and immobilization of sperm in the vagina
make the rapid transport of sperm to a more
favorable environment essential

12. Spermatozoa must remain in the female reproductive
tract for some period after ejaculation before they are
capable of fertilization.
The process that occurs here to convert non-fertile
spermatozoa to fertile spermatozoa is termed
capacitation.
This process includes changes in or removal of
components of the outer acrosome and plasma
membranes so that acrosomal enzymes can later be
released and activated.

13. Part of the natural capacitation process requires
exposure of the spermatozoa to female reproductive
tract secretions, but capacitation of spermatozoa can be
done in vitro using experimentally derived protocols and
solutions.

18. INTERACTION BETWEEN SPERM AND
FEMALE TRACT
There are two main categories of interactions of
sperm with the female reproductive tract, namely,
physical and molecular.
The physical category includes the swimming
responses of sperm to the microarchitecture of the
walls of the tract, to fluid flows, and to fluid
viscoelasticity.

19. Molecular interactions include communications of
sperm surface molecules with receptors in the
epithelial linings of the tract. Indirect molecular
interactions, such as effects of tract secretions on
sperm, effects of seminal plasma on the tract, or
interactions of sperm with immune cells that enter
the lumen of the tract.

20. PHYSICAL INTERACTIONS
Surfaces
The architecture of cell surfaces can affect the direction
of sperm movement. It has long been observed that
sperm tend to accumulate at surfaces, particularly the
surfaces of slides and coverslips.

21. Fluid flows
The fluid in the lumen of the female reproductive tract is
rarely static: ciliary beating, contractions of smooth
muscle in its walls, and secretion of fluids into the lumen
create fluid flows, fluid flow and surfaces can act
together to guide sperm through parts of the female
tract.
The microgrooves provide a privileged pathway toward
the uterus for sperm, because the grooves would protect
sperm from the strong outflow of fluids through the
center of the cervical canal.

24. Viscoelasticity
Sperm encounter viscous fluids in the female tract, some
of which contain significant elastic properties. These
include estrous cervical mucus.
Viscoelastic fluids can reduce the swimming velocity of
sperm, but can also modify the bending pattern and
subsequent swimming trajectories of sperm. the
viscoelasticity of the cumulus matrix could assist
hyperactivated sperm in penetrating the cumulus to
reach the zona pellucida. The zona pellucida itself has
also been characterized as viscoelastic

25. MOLECULAR INTERACTIONS
Sperm interaction with epithelium lining the uterotubal
junction
The anatomy of the uterotubal junction varies
considerably among mammalian species. Nevertheless, in
most species, the passageway for sperm is narrow and
the mucosa that forms the inner surface is thrown into
folds that create a complex, branched passageway.

26. The passageway is known to be quite narrow in some
species, such as the cow Bos Taurus.
The actual mechanism of how the uterotubal junction
responds to a cell surface protein by enabling sperm to
pass into the oviduct remains unknown.

27. Sperm interactions with epithelium in the oviductal
reservoir
Many of the sperm that pass into the oviduct soon bind
to the oviductal epithelium. The buildup of bound sperm
has been found to create a storage reservoir in a
number of species. As the time of ovulation draws near,
there is some evidence that sperm begin to detach from
the epithelium, and may then reattach and detach
several times before they move out of the storage
region.

28. The fertilizing capacity of sperm may be maintained by
their interaction with oviductal epithelium.
Changes in the hormonal state of oviductal epithelium
after ovulation were not found to reduce the density
numbers of sperm that bound to epithelium; therefore, it
appears that epithelium does not release sperm by
reducing available binding sites, at least in cattle.
Instead, current evidence indicates that a change in
sperm enables them to detach from epithelium.

29. Detachment of sperm from oviductal epithelium
Two changes that occur in sperm during the process of
capacitation may play a role detachment:
(1) modification of cell surface proteins.
(2) hyperactivation of motility.
Modification of sperm surface proteins could reduce
binding affinity for oviductal receptors. Hyperactivation
could provide the force necessary for sperm to pull
away from the oviductal epithelium.

30. As sperm undergo capacitation, the carbohydrate
portions of molecules responsible for binding sperm to
epithelium may be lost from the sperm surface or
modified. Capacitated hamster sperm were no longer
labeled over the acrosomal region by fetuin, indicating
that they had lost the ability to bind to oviductal
epithelium via sialic acid. Furthermore, fewer proteins
extracted from capacitated sperm were labeled by
fetuin or sialic acid LFA lectin on western blots

31. Sperm interactions with oviductal epithelium in
the upper oviduct
sperm bound equally well to the epithelium of the
isthmus and the ampulla.

32. CONCLUSION
Diagnosis of the causes of infertility could be greatly
improved if more were known of the means by which
sperm travel through the female reproductive tract and
the mechanisms that regulate the movement of sperm.

33. REFERENCES
•F. Lopez-Gatius. Site of semen deposition in cattle.1999.
•Susan S. Suarez. Mammalian Sperm Interactions with the Female Reproductive
Tract. 2017.
•H. W. HAWK. Sperm Survival and Transport in the Female Reproductive Tract. 1982.
• Ferenc Husvéth. Physiological and reproductional aspects of animal production .
2011.
•D Rath1, HJ Schuberth2, P Coy3 and U Taylor. Sperm Interactions from Insemination
to Fertilization. 2008.

34. Thanks