Male
reproductive system
Anatomy
The male
reproductive organs consist of the tests and the accessory organs like
epididymis , vas deferens, seminal vesicles ejaculatory duct, prostate glad and
urethra. The supporting structures are the scrotum, penis and spermatic cords.
The organs ar invoved in the production and ejaculation of sperms and thus are
closely related to fertility in the male.
Scrotum and Testes –The scrotum is a skin covered pouch suspended outside the abdominal
cavity. It contains the testes, epididymis and spermatic cord. The temperature
of the scrotum is maintained at 35c. this allows for optimal conditions for
sperm production. If the temperature drops too low, the scrotal muscle contacts
involuntarily to bring the testes closer to the heat of the bidy and vice
versa. A high scrotal temperature does not affect testosterone production but
spermatogenesis is impaired vesicles. It also stimulates the development of
masculine secondary sex characteristics. Sertoli cells in the testes nourish
the developing spermatozoa.
Vas Deferens –The vas deferens is an uncoiled duct
that funnels the spermatozoa from the tail of the epididymis. The majority of
the sperms are stored in the enlarged end of the vas deferens knows as the
ampulla. If the sperm are not ejaculated , they soon degenerate and are
adsorbed in these tubules. high scrotal temperature does not affect
testosterone production but spermatogenesis is impaired vesicles. It also
stimulates the development of masculine secondary sex characteristics. Sertoli
cells in the testes nourish the developing spermatozoa.
Vas Deferens –The vas deferens is an
uncoiled duct that funnels the spermatozoa from the tail of the epididymis. The
majority of the sperms are stored in the enlarged end of the vas deferens knows
as the ampulla. If the sperm are not ejaculated , they soon degenerate and are
adsorbed in these tubules.
Ejaculatory Ducts- The ampulla of the vas deferens
combines with the duct from the seminal vesicle to from the ejaculatory ducts.
The ejaculatory ducts are two short tubes that descend through the prostate
gland to the urethra . From there the urethra passes out of the abdominal
cavity and down the middle of the penis to the tip. The seminal vesicles are
two saclike structures located within the peritoneal cavity and are lined with
secretory epithelium that secrets viscous alkaline yellowish nutritive fluid.
It mixes with sperm in the ejaculation of the sperm out of the urethra. On
ejaculation the sperms become motile.
Normally 2
to 5 ml of the ejaculate is expelled from the body. The semen is a viscous
milky fluid and normally contains millions of actively motile sperm.
The tests
contain the tightly coiled seminiferous tubules. The seminiferous tubules are
lined with that produces sperm. Approximately 2x 10 sperms are produced in the
testes each that from the time of sexual maturity to old age. Interspersed between the seminiferous tubules of the testes are a number of interstitial
cells called Leydig cells. These cells produced and secrete testosterone.
Testosterone stimulated the pubertal
growth of the male genitalia, prostate and seminal vesicles.
SPERMATOGENESIS
The entire process by which spermatogonial sperm cells divide and
spermatozoa is known as follows :
1.
Primordial undeveloped sperm cells divide and transform into spermatocytes.
2. Spermatocytees mature through several stages and then
undergo cellular division so that their number of chromosomes is reduced from
46 to26 (meiosis).
3.The spermatocytes further divide and become ells known as
spermatids.
4.The spermatids develop into sperpmatozoa. This process is
called spermiogenesis during which the transforming cells are
attached to the Sertoli
cells.
5. After release from the Sertoil cells the spermatozoa are
stored in the epididymis where maturation continues.
6. The conversion of a spermatogonium into a fully different
spermatozoon takes about 53 days .
7. Passage through epididymis ad vas deferens takes about 10
days.
Structure of spermatozoa
A single sperm is a microscopic motile germ cell that carries
the male chromatin material. It consists of an oval head short neck and body.
The head is almost entirely nuclear material rich in DNA and containing all the
paternal genes. The tail is long and its motion causes the sperm to be actively
motile. The mitochondria are found in the neck and supply the energy for the
vigorous movement of the sperm.
Hormonal control of
spermatogenesis
During puberty,
between the ages of 10 to 15 the anterior pituitary gland begins to
secrete gonadotropic hormones under the influence of GnRH from hypothalamus.
FSH initiates and maintains spermatogenesis by the tubules. LH causes secretion
of testosterone by the interstitial cells. Testosterone inhibits LH secretion
by acting directly on the anterior pituitary and by inhibiting the secretion of
GnRH from the hypothalamus, inhibits FSH
secretion. In response to LH , some of the testosterone secreted from
Leyding cells bathes the seminiferous epithelium and provides the high local concentration
of androgen to the Sertoli cells that is necessary for normal spermatogenesis.
INTRODUCTION TO IUI
Intra Uterine Insemination is one of the simple
techniques of Assisted Reproductive Medicine treating infertility by artificial
insemination. Insemination can be performed using the husband’s sperm or with
sperm from a donor which is tested frozen quarantined and then re tested.
The therapy is relatively minimally invasive and an
uncomplicated procedure. Execution of IUI is simple and doesn’t demand any
special qualification.
In ART centers, IUI represents the first step of the therapy
in the treatment of infertility. It is a cost effective, simple method which
can be learnt easily.
Setup of an IUI laboratory is also within the reach of most
gynecologists taking interest in infertility management.
IUI :
What we as Gynaecologits need to be aware of ??
Point
1:-Why should we recommend the couple for IUI?? What is the success rate ? Success rate or Outcome of IUI?? Ans:- It varies on cause of IUI. But the fact
remains that Proper selection and well performed IUI results in pregnancy rates
ranging between 5%-(oligozoospermia, Astnenozoospermia ) to 30% (coital problems ).
Point
2:-History of IUI: What was in two centuries
back?? It was John Hunter who was credited with first report of successful
insemination by semen from husband with hypospadias. In 1890 Dickinson first
used artificial insemination with donor sperm in England. The first successful
freezing of human semen was reported in 1953 by Bunge & Sherman.
Point 3: Semen –where from?? Semen source ?
Semen is usually taken from husband(coital probkems, oligozoospermia,
Astnenozoospermia or a donor depending upon the indication. All country & Cmmitte guidelines forbid the use of fresh semen from
donors because of the fear of HIV .So,frozen semen can only be used
after a quarantine period of 3-6 months.
What
is te principle behind the IUI Procedute??
a. :In this process of IUI:- The procedure works in the following
principle:- a)Selects most motile sperm fraction removing the debris and dead
sperm.
b. Removes prostaglandins
present in high concentration in the seminal plasma and thus reduces the risk
of uterine cramping.
c. Removes infectious
agents (organism/ bacteria ) and leucocytes.
d. Removes antigenic
proteins in the seminal plasma and thus improve prospects of fertility.
e. Helps in the
capacitation of spermatozoa.
f. Sperm washing media
provide nutritional support for the spermatozoa and keep their activity for
longer time.
What
is being exactly achieved by carrying out the procedure of n Intrauterine Insemination ??
a) Accurate timing with ovulation by serial
follicular monitoring b) Overcomes
coital difficulties c) by passes the cervical mucous barrier which may be
hostile to the sperm d) Increases the density of sperm in the upper genital
tract. f)? The questionable indication is if the cervix is stenosed :-Overcomes
anatomical cervical problems like stenotic cervix deviated or very kinked.
The
procedure itself:-Controlled Ovarian stimulation:
a. Multiple ovulations expose
spermatozoa to multiple oocytes for potential fertilization. Hopefully one ova will
be fertilized if there are two mature
eggs released.
b. Controlled ovulation
induction corrects subtle ovulation defects.
c. Better control over
timing of ovulation.
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