Embryology Flashcards
Explain meiosis.
Occurs during gamete production.
Two cell divisions; forms 23 chromosomes and 1N of DNA
Allows exchange of small maternal/paternal material via crossing over.
Explain the process of Oogenesis.
- Primordial germ cells arrive in the ovary of week 6, become oogonia.
- Oogonia enter meiosis I, form primary oocytes. Formed in 5th month of life, remain dormant in prophase I.
- Ovarian cycle promotes primary to secondary oocyte and 1st polar body.
- Second oocyte begins Meiosis II.Ovulation occurs during metaphase until fertilization.
- Formation of mature oocyte (23,1N) and second polar body at fertilization.
Hormone control of female reproductive cycle. Explain the process.
- Release of GnRF, gonadotropin-releasing factor.
- GnRF triggers adenohypophysis to release FSH, LH.
- FSH stimulates 2nd follicle.
- Estrogen secreted by granulosa cells from the secondary and Graafian follicle.
- Estrogen stimulates uterus to enter proliferative phase.
- LH stimulates ovulation.
- Progesterone secreted by granulosa cells after ovulation.
- Progesterone stimulates uterus to enter secondary phase.
What is the process of capacitation?
The removal of sperm glycosyltransferase and protein coat.
What are common amongst elderly men and women.
Women: Risk of trisomy 21 bc of nondisjunction.
Men: Achondroplasia- retarded bone growth with normal head/trunk.
Marfan Syndrome:
What is Kallmann syndrome?
Genetic disorder stemming described as hypogonadotropic hypogonadism. Where low levels of GnRF–> low FSH/LH–>low testosterone.
(Male Infertility)
List factors that could contribute to male infertility.
drugs, Klinefelter syndrome, seminoma, rheumatoid arthritis, epididymitis, impotence, ductus deferens obstruction.
List factors for female impotence.
- Anovulation
- Premature ovarian failure
- PID
- Polycystic Ovarian Syndrome
- Endometriosis
Anovulation
absence of ovulation bc of low FSH/LH. Corrected with clomiphene citrate. Competes for spot with estrogen, inhibits the negative feedback loop of estrogen to promote FSH/LH and ovulation.
Premature Ovarian Failure
Loss of ovarian function before age 40. Mostly idiopathic but sometimes from autoimmune disease.
Pelvic Inflammatory Disease (PID)
Refers to infection of uterus, uterine tubes, and/or ovaries leading to inflammation and scar. Normally from clamydia or gonorrhea.
Polycystic ovarian syndrome
Endocrine disorder of oligo-ovulation(irregular ovulations), androgen excess, ovarian cysts.
Endometriosis
Foci of endometrial tissue in abnormal locations outside of uterus.
What are gametes?
Descendants of primordial germ cells of the yolk sac.
Migrate to the gonad region.
Produced by oogenesis or spermatogenesis via meiosis.
Gametogenesis
Starts at meiosis.
Produces secondary oocytes (1)
Produces sperm (4)
