Developmental Biology Week 2

Question 1

Gonadotropin-releasing hormone (GnRH)

Answer 1

produced by hypothalamus, stimulates anterior pituitary to produce FSH and LH

Question 2

Follicle Stimulating Hormone

Answer 2

Produced by anterior pituitary, stimulated by GnRH

Question 3

Luteinizing Hormome (LH)

Answer 3

produced by anterior pituitary, stimulated by GnRH

LH surge stimulates ovulation

Question 4

Estrogen

Answer 4

Produced in ovaries and stimulated by FSH and LH

Question 5

Progesterone + Estrogen

Answer 5

helps the uterine mucosa into progestational/secretory phase in preparation for implantation

Question 6

Corpus Luteum

Answer 6

produces high levels of progesterone and also some Estrogen which inhibits GnRH secretion

Question 7

How is the ovulated oocyte transported to the uterus?

Answer 7

The occyte is captured by sweeping movement of the fimbriae of the uterine tube and by the motion of cilia on the epithelial lining

Question 8

Where does fertilization occur?

Answer 8

The ampulla of uterine tube

Question 9

What happens if there is no fertilization?

Answer 9

Lutean cells undergo apoptosis -> corpus albicans-> decrease progesterone eventually leads to menstrual bleeding

Question 10

What happens if there is fertilization?

Answer 10

hCG is secreted by syncytiotrophoblast -> further growth

Progesterone is produced until the end of the 4th month: trophoblastic secretion of progesterone becomes adequate

Question 11

Capacitation

Answer 11

maturation of sperm in female reproductive tract -> removal of glycoprotein and seminal plasma proteins from sperm

Question 12

acrosome reaction

Answer 12

release of enzyme by sperm to dissolve zona pellucida

starts as soon as the sperm comes in contact w/ corona radiata

Question 13

Entry of sperm into the oocyte triggers:

Answer 13

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

Question 14

Cortical reaction

Answer 14

hardening of zp and inactivation of sperm receptors

Question 15

The results of fertilization

Answer 15

restoration of diploid number of c-somes

sex determination

initiation of cleavage

Question 16

blastomere

Answer 16

2,4, 8 cell stages

Question 17

Morula

Answer 17

16 cells: inner mass embryo proper -> tissues

outer cell mass: trophoblast -> placenta

Question 18

Blastocyst

Answer 18

ZP degenerates -> uterine fluid penetration-> blastocele (cavity) formation - inner cell mass -> embryoblast

outer cell mass ->trophoblast, epithelial wall

Question 19

Uterine cycle

Answer 19

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

Question 20

epiblast

Answer 20

tissue type derived from inner cell mass of blastocyst

Question 21

spermiogenesis

Answer 21

where haploid sperm cells differentiate towards becoming mature sperm

Happens in testes

Question 22

spermiation

Answer 22

After spermiogenesis, each spermatid disengages excess cytoplasm and is released into the lumen of the seminiferous tubles

Question 23

spermatogenesis

Answer 23

spermatagonia -> spermatocytes -> spermatids -> sperm (spermatazoa)