Reproductive system indonesia fasciola hepatica taeni solium and ascaris
Answers
Answer:
Mark it as brainliest ans plz
Explanation:
Ascaris
Reproductive System:
Only sexual reproduction occurs in Ascaris. Sexes are separate and there is distinct sexual dimorphism between male and female Ascaris.
Male Reproductive System:
Reproductive organs of male ascaris include a testis, a vas deferens, a seminal vesicle, an ejaculatory duct, cloaca and penial setae.
1. Testes:
Male ascaris is monorchis i.e., it has a single testis. The testes are a long, thin and coiled tube-like structure. It continues into a vas deferens. The testis has a cavity lined by a single layer of cuboidal cells. It acts as “growth zone”. It has, in its cavity, a semisolid axial core of rachis of cytoplasm around which the spermatogonia are irregularly attached while these progressively undergo maturation or spermatogenesis to form sperms.
2. Vas deferens:
This is shorter and less coiled tube than testis.
3. Seminal vesicle:
This is a long, straight and relatively much thicker tube into which the vas deferens opens. It serves to store the mature sperms.
4. Ejaculatory duct:
The seminal vesicle leads into a short, narrow and highly muscular and glandular ejaculatory duct. This duct opens behind into the last part of rectum from the ventral side.
5. Cloaca:
The last part of rectum, located behind the opening of ejaculatory duct serves as cloaca, because it receives both faeces and sperms. It opens out by the cloacal aperture.
6. Penial setae:
Two small, contractile penial sacs open into the cloaca on dorsal side. Each sac secretes and contains a small needle-like penial or copulatory seta or spicule of cuticle. Protractor and retractor muscles, associated with the wall of each penial sac respectively serve to protrude and retract the contained spicule through the cloacal aperture. During copulation, the spicules protrude out to keep the female’s vulva open. Sperms of Ascaris are tail, asymmetrical and amoeboid
Female Reproductive System:
The female genitalia include ovaries, oviducts, uterus and vagina.
1. Ovaries:
Female Ascaris is didelphic i.e., it has two ovaries. It is long, thin and coiled tube-like structures. The oogonia are formed by budding from a single large germinal cell forming the proximal “germinal zone” of each ovary. In the remaining part of an ovary, i.e., the “Growth zone”, oogonia undergo oogenesis or maturation, The oogonia after completing the first maturation divisions, become secondary oocytes and reach the oviducts.
2. Oviducts:
Each ovary leads into a long and coiled oviduct.
3. Uterus:
Each oviduct leads into a much thicker and long uterus. The uterine wall thick and formed of a layer of tufted secretory cells surrounded by a muscular layer Uteri serve to store the eggs after fertilization.
4. Vagina:
The uteri open into short and relatively narrow vagina. The wall of vagina is quite muscular and contractile. The vagina opens out by slit-like female pore or vulva.
Life Cycle:
Copulation and fertilization:
Ascaris copulates in the intestine of the host. The sperms by amoeboid movement reach the seminal receptacle of the uterus and fertilize the ovum. Fertilized eggs pass one-by-one into the uteri. A sphincter muscle regulates their passage from the seminal receptacle into the remaining part of a uterus, (fig. 9.17).
Mammilated Eggs:
Immediately after fertilization, the cell membrane of a zygote separates from its cytoplasm and, thus, becomes a fertilization membrane. Soon, it is fortified by protein and glycogen granules extruded by the cytoplasm. Thus, it transforms into a thick and hard chitinoid shell.
As the eggs move to the uteri, the cells of uterine wall secrete a brownish albuminous cyst around each egg. On drying, this cyst becomes hard, rough and warty. Thus, by the time an egg reaches the distal part of a uterus, it becomes enclosed in three, highly resistant protective coverings and bears distinct warts or tubercle upon its surface. It is called a mammilated egg.
Cleavage and early embryonic development:
Embryonic development is possible in Ascaris only outside the body of human host in soil, because it requires low temperature, more O2 and suitable moisture. Cleavage is holoblastic, but of a peculiar spiral and deteminate type. In quite early stages, different blastomeres of the embryo become earmarked to form different organs of future juvenile ascaris.