The reproductive systems of male and female Ascaris lubricoides worms are described. The male system includes a single coiled testis, vas deferens, seminal vesicle, ejaculatory duct, and two penial spicules. The female system includes two long coiled ovaries, oviducts, uteri which store fertilized eggs, and a vagina. Gametes are formed through a process called telogony, where gametogonia bud off from the gonads and differentiate into gametocytes as they move through zones of proliferation, growth, and maturation.

1. Reproductive sytem of Ascaris lubricoides

2. Reproductive sytem of Ascaris lubricoides
Introduction:
 Male and female sexes are separate in Ascaris
 Shows sexual dimorphism.
 Males are smaller, also have a curved tail with pre and post anal papillae,
cloaca and a pair of spicules.
 The gonads are long, tubular and coiled.
 Gonads are attached at the genital pore in females and at the cloaca in the
male worms

3. Male Reproductive sytem
The male reproductive organs are confined to the posterior half of the
pseudocoel.

4. 1. Testis:
 A single testis is present in the roundworms
which extend to the middle of the body.
 The testis is in the form of long- thread like
highly twisted tube.
 The wall of testis is made up of single layer
of cuboidal cells covered by basement
membrane.
 The central axis of the testis is in the form of
cytoplasmic rachis around which clusters of
amoeboid sperms are present in various
stages of development.
2. Vas deferens:
 The distal part of the testis continues as a
short, thick and twisted tube called as vas
deferens.
 This part has a lumen which replaces the
central rachis of the testis.

5. 3. Seminal vesicle:
 Seminal vesicle is a thick, wide and
muscular continuation of the vas
deferens.
 It lies in the posterior third of the
pseudocoel below the intestine.
4. Ejaculatory duct:
 The terminal part of the seminal
vesicle narrows down to form highly
muscular ejaculatory duct.
 The ejaculatory duct joins to the
rectum to form cloaca.
 This duct contains a number of
prostatic glands whose secretions help
in copulation.

6. 5.Penial spicules:
 Penial spicules are located in the spicular pouch.
 Two spicular pouches are situated on the dorsal side of the cloaca.
 These are basically evaginations of the cloaca.
 The spicules help in opening female gonopore during copulation.

7. Female Reproductive sytem
Female reproductive organs lie in the
posterior two third of pseudocoel. The female
reproductive organs include the following,
1. Ovaries:
 Two long, twisted, thread-like ovaries are present
in Ascaris.
 The ovary wall consists of single layer of cuboidal
epithelial cells lined externally by a basement
membrane.
 The central axis of the ovary is in the form of
cytoplasmic rachis around which groups of ova are
present.
2. Oviducts:
 A thick, wider and twisted oviduct arises from the
distal end of each ovary.
 The wall is similar to that of the ovary.
 The major difference is that the cytoplasmic rachis
of the ovary is replaced by lumen in the oviducts.

8. 3. Uteri:
 Each of the oviducts continues as a much
wider and thicker and untwisted tube called
the uterus.
 The walls of both uteri are composed of tufted
cells surrounded by a muscle layer with inner
circular and outer oblique fibers.
 The uterus serves as a storage spot for the
fertilized eggs which are enclosed in the
shells.
4. Vagina:
 At the anterior one third of the body the two
uteri combine to form a short and highly
muscular tube called vagina, having an inner
lining of the cuticle.
 Vagina opens to the outside through female
gonopore or vulva.

10. Formation of gametes:
The gametogonia are budded off from the proximal end of the
gonad.
These gametogonia undergo gametogenesis as they move
towards the distal end of the gonad.
This method of formation of germ cell is called as telogonic
and it occurs commonly in most nematodes.
In a telogonic gonad, the following three zones can be
identified
Germinal zone:
 This zone is also known as proliferation zone.
 This zone lies at the proximal end of the gonad.
 This zone is constituted by a single large terminal cell.
 In front of this terminal cell, a large apical cell is present.
 From this apical cell, gametogonia are budded.

11. Growth zone:
 Growth zone follows the germinal zone.
 In this growth zone, the gametogonia lie attached to the
cytoplasmic rachis.
 Here it grows and gets differentiated into amoeboid
gametocytes.
Maturation zone:
 Maturation zone is the distal most zone, where the gametocytes
separate from the cytoplasmic rachis to undergo maturation.
 After maturation, gametocytes transform into gametes.
 The maturation zone is followed by gonoduct.
 The sperms are amoeboid whereas the ova are elliptical in shape.
 The ova at this stage are secondary oocytes which have
developed from a single maturation division.

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