Delayed puberty is when a person lacks or has incomplete development of specific sexual characteristics past the usual age of onset of puberty. The person may have no physical or hormonal signs that puberty has begun. In the United States, girls are considered to have delayed puberty if they lack breast development by age 13 or have not started menstruating by age 15. Boys are considered to have delayed puberty if they lack enlargement of the testicles by age 14. Delayed puberty affects about 2% of adolescents.Most commonly, puberty may be delayed for several years and still occur normally, in which case it is considered constitutional delay of growth and puberty, a common variation of healthy physical development. Delay of puberty may also occur due to various causes such as malnutrition, various systemic diseases, or defects of the reproductive system (hypogonadism) or the bodys responsiveness to sex hormones.Initial workup for delayed puberty not due to a chronic condition involves measuring serum FSH, LH, testosterone/estradiol, as well as bone age radiography. If it becomes clear that there is a permanent defect of the reproductive system, treatment usually involves replacement of the appropriate hormones (testosterone/dihydrotestosterone for boys, estradiol and progesterone for girls).
This allows for parasitic worms to attach to their host by penetrating the host’s tissue with spines lining the acetabulum organ. In trematodes, the oral sucker is linked to the pharynx via a canal composed of meridional, equatorial, and radial muscle fibers. Together, the mouth, pharynx, and esophagus form the foregut in Trematodes.Male reproductive system: The male reproductive system generally includes two testes, while some species may have more. Along with this, the size and position of the testes in the body may vary depending on the species. Due to this species-level variation, the male reproductive system can be very useful in species identification. Sperm production, or spermatogenesis, occurs in the testes. Spermatogenesis in Trematodes produces biflagellate sperm or sperm with two tails. This phenomenon occurs across very few invertebrate and vertebrate species. Sperm is stored in the seminal vesicle, this organ is connected to the testes by the vas deferens.Female reproductive system: The female reproductive system consists of one ovary in Trematodes. The location of the ovary varies between species, making the female reproductive system useful in species identification. The oocytes are released from the ovary via the oocapt, from here, the stored sperm in the seminal vesicles will meet with the oocyte. In the Mehlis’ gland, the oocyte and sperm will be joined and start developing. As the embryo is forming, the vitelline ducts will begin to release materials that will be used to create the eggshell around the embryo. Finally, the Laurers’ canal will lead outside of the body.