Prenatal And Postnatal Developments Of Gonads in animal

1. Comparative Reproduction
Prenatal And Postnatal Developments Of Gonads Of The Farm Animals
By, Shazinosh

2. • Gonads are the female and male reproductive
organs. Testes are the male gonads and ovaries
in females responsible for the production of male
and female gametes.
• Gonad is composed of cells derived from four
lineages: supporting cells, steroid-producing
cells, connective tissue cells, and germ cells.
• Gonads are also responsible for producing sex
hormones required for the development and
growth of primary and secondary sexual
characteristics
GONADS

3. Female Gonad Hormones
The major hormones of the ovaries are progesterone and estrogens.
GONADAL HORMONES
Male Gonad Hormones
Androgens are hormones that majorly influence the development of
the male reproductive system. Testosterone
Androstenedione – These are the hormones that act as a precursor
to estrogens and testosterone.
Inhibin – These hormones inhibit the release of FSH and thought to
be involved in sperm cell regulation and development

4. DEVELOPMENTS OF GONADES

5. Prenatal Development OF GONADS
In mammals, females have two X
chromosomes whereas males have
one X and one Y chromosome.
Animals with a single X chromosome
and no Y chromosome (XO) are
phenotypically females, indicating that
the Y chromosome dictates male
development.

6. Sex differentiation is genetically determined.
The fetal gonads arise from the indifferent primordial
ridges and develop into a testis or an ovary.
During gestation period the primordial germ cell
move from yolk sac through dorsal mesentery and
going to posterior body wall
These primordial germ cell stimulate coelomic
epithelium to form longitudinal ridges which non as
gonadal ridges
If embryo is a male there is XY chromosome
On this Y chromosome there is gene SRY
SRY code “testis determining factor” (TDF> trough
transcription
Active some autosomal gens SOX 9
Because of SRY and sox 9 gen
Genital ridges will become tastes
GONADAL SEX Differentiation

7. Prenatal Development
• Females have two XX chromosomes
• There is no SRY gens because of no
Y chromosome
• Genetical rides is automatically
converted in to ovary and WNT4 gen
and FOXL2 help in formation of
ovary’s
• The normal development of the ovary
and follicles depends on the presence
of germ cells. The absence or an
excess of X chromosome (XO or XXX)
results in nonviable oocytes

8. • The testes develop in the abdomen.
• Testis connected to mesonephric tubules and duct to
form the epididymis, ductus deferens, and vesicular
gland.
• The prostate and bulbourethral glands form. From
the embryonic urogenital sinus . And the penis
develops at the orifice of the urogenital sinus.
Postnatal Development
a, Ampulla; bu, bulbourethral gland; cap. e, caput epididymidis, caud. e, cauda epididymidis; cp, left crus
of penis, severed from the left ischium; dd, ductus deferens; ds, dorsal diverticulum of prepuce; es,
prepenile prepuce; fe, free part of the penis; is, preputial fold; pg, prostate gland; r, rectum; rp, retractor
penls muscle; s, scrotum; sf, sigmoid flexure; t, testis; up, urethral process; vg, vesicular gland.

9. • Two agents produced by the fetal testis
are responsible for this differentiation and
development
• Fetal androgen help development of the
male reproductive tract.
• “Müllerian inhibiting substance, is
responsible for suppression of the
paramesonephric (Müllerian) ducts from
which the uterus and vagina develop
The mesonephric duct is known as the
wolffian duct.
• The wolffian duct persists to act as the
male genital duct while it atrophies in the
females.

10. Descent of the Testis
• During testicular descent the gonad migrates
caudally Within the abdomen to the deep inguinal
ring.
• Abdominal wall emerge from superficial inguinal ring,
• The testis completes its migration by passing fully
into the scrotum.
• Descent is preceded by vaginal process a
peritoneal sac extending through the abdominal wall
and enclosing the inguinal ligament of the testis.
• The inguinal ligament of the gonad is often called the
gubernaculum testis,
• The time of descent varies

11. Sometimes the testis fails to enter the scrotum. In
this condition (cryptorchidism), the special thermal
needs of testis and epididymis are not met, although
Bilaterally cryptorchid males show more or less
normal sexual desire but are sterile. Occasionally
some of the abdominal viscera pass through the
orifice of the vaginal process and enter the scrotum;
CRYPTORCHIDISM

12. The internal genital organs (the first
four components) are supported by
the broad ligament. This ligament
consists of the mesovarium, which
supports the ovary; the mesosalpinx,
which supports the oviduct; and the
mesometrium, which supports the
uterus.
Postnatal Development

13. Postnatal Development
• The reproductive tracts of all farm animals grows in size relative
to overall body size and undergoes histologic differentiation
• Functional competence is not achieved simultaneously
• At puberty all the components of the reproductive system
develop to be functional.
• During the post pubertal period, development continues and the
reproductive tract reaches full sexual maturity months or even
years after the age of puberty.
• Significant increases in testicular weight, daily sperm production,

15. REFERENCE