1. (10pts) As you know it takes approximately 12-14 years for a child to reach “
ID: 3518531 • Letter: 1
Question
1. (10pts) As you know it takes approximately 12-14 years for a child to reach “sexual maturity” – meaning that sex organs are matured and sex cells are likely to be “functional”.
1. Explain where in embryogenesis the cells that become eggs and sperms
come from.
2. How do these cells end up in the “organs” that hold them until maturation?
Describe how each of those organs develop – completely!
3. During the years after birth explain how the germ cells mature AND what
signals make a male and female release their gametes.
4. Describe one thing that may cause infertility and explain what treatment
might help that couple conceive
Explanation / Answer
1 ans. In humans Primordial germ cells give rise to cells that become eggs and sperms. these primordial germ cells are derived from epiblast cells and are formed during the second week.
2 ans. The primordial germ cells migrate through the yolk sac wall and the masentry of hind gut to reach genital ridge or gonodal ridge and enter into gonads.
Initially gonads are in a thickening of the mesothelial layer af peritoneum. later they become gonodal ridge , which in turn develop into gonad. in females it is called ovary and in males it is called testis. this differentiation is based on the gene on Y chromosome called as SRY gene
In females primordial germ cells multiply by mitosis and once they have reached the gonadal ridge they are called as oogonia. This oogonia is surrounded by a connective tissue called as pre- granulosa cells which forms ovarian follicles. Gubernaculum which is the ovarian ligament , which is in contact with the uterus, helps desccent of ovaries.
In males, primordial germ cells coalase to form primordial testis. Later sertoli cells , derived from coelomic epithelium are morphologically recognised as testicular cords..Leydig cells appear at 6-8 weeks. These secrete testorone..At 9 weekslabioscrotal swellings fuse to form the scrotum. testorone induces development of the epididymus, vas deferens and seminal vescilesDuring this stage the testis move from genital across the pelvis to lie at the internal inguinal ring. testis descents at 10-15 weeks . The gubernaculumthat connects testis to lower abdomen, subsequently pulls and translocates the testis down into the developing scrotum.
3 ans. male germ cell differentiate in seminiferous tubules. it is in the following stages.
THis entire process is called spermatogenesis which is stimulated by the hormones FSH and testosterone
In female oogonia progress into meiosi and by 5th day after birth, they reach diplotene stage of first meiotic division are arrested till sexual maturation. the second phase of maturation is started with onset of puberty. the hormones responsible are estrogen and progesterone
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.