Developmental Biology Week 2 Flashcards
Gonadotropin-releasing hormone (GnRH)
produced by hypothalamus, stimulates anterior pituitary to produce FSH and LH
Follicle Stimulating Hormone
Produced by anterior pituitary, stimulated by GnRH
Luteinizing Hormome (LH)
produced by anterior pituitary, stimulated by GnRH
LH surge stimulates ovulation
Estrogen
Produced in ovaries and stimulated by FSH and LH
Progesterone + Estrogen
helps the uterine mucosa into progestational/secretory phase in preparation for implantation
Corpus Luteum
produces high levels of progesterone and also some Estrogen which inhibits GnRH secretion
How is the ovulated oocyte transported to the uterus?
The occyte is captured by sweeping movement of the fimbriae of the uterine tube and by the motion of cilia on the epithelial lining
Where does fertilization occur?
The ampulla of uterine tube
What happens if there is no fertilization?
Lutean cells undergo apoptosis -> corpus albicans-> decrease progesterone eventually leads to menstrual bleeding
What happens if there is fertilization?
hCG is secreted by syncytiotrophoblast -> further growth
Progesterone is produced until the end of the 4th month: trophoblastic secretion of progesterone becomes adequate
Capacitation
maturation of sperm in female reproductive tract -> removal of glycoprotein and seminal plasma proteins from sperm
acrosome reaction
release of enzyme by sperm to dissolve zona pellucida
starts as soon as the sperm comes in contact w/ corona radiata
Entry of sperm into the oocyte triggers:
cortical and zona reactions prevent polyspermy, oocyte completes meiosis II, egg is activated - the nucleus inside the egg is formed w/ both maternal and paternal genome
Cortical reaction
hardening of zp and inactivation of sperm receptors
The results of fertilization
restoration of diploid number of c-somes
sex determination
initiation of cleavage
blastomere
2,4, 8 cell stages
Morula
16 cells: inner mass embryo proper -> tissues
outer cell mass: trophoblast -> placenta
Blastocyst
ZP degenerates -> uterine fluid penetration-> blastocele (cavity) formation - inner cell mass -> embryoblast
outer cell mass ->trophoblast, epithelial wall
Uterine cycle
Proliferative phase: end of mentrual phase, estrogen regulated
Progestional (secretory phase): 2-3 days after ovulation, corpus luteum secretes progesterone to prepare the uterus for implantation
Menstrual phase: basal layer of endometrium remains for regeneration
epiblast
tissue type derived from inner cell mass of blastocyst
spermiogenesis
where haploid sperm cells differentiate towards becoming mature sperm
Happens in testes
spermiation
After spermiogenesis, each spermatid disengages excess cytoplasm and is released into the lumen of the seminiferous tubles
spermatogenesis
spermatagonia -> spermatocytes -> spermatids -> sperm (spermatazoa)
