embryology objectives

msu dpt embryology

at what stages of meiosis is oocyte maturation arrested?

arrests at prophase 1. resumes meiosis at ovulation, completing meiosis at fertilization.

what are two vulnerable periods of chromosomal abnormalities

gametogenesis and early cleavage stage

what is mosaicism

phenotypic variation due to some cell lines having abnormal amounts of chromosomes

what happens when homologous chromosomes fail to separate in telophase?

monosomy or trisomy (down syndrome)

what is the role of the hypothalamus in a woman’s monthly cycle?

secretes gonadotropin releasing hormone rhythmically, setting the menstrual rhythm

what is the role of the pituitary in a woman’s monthly cycle?

takes gnrh from hypothalamus and makes gonadotropin. directly triggers ovulation

what is the role of the ovary and uterus in a woman’s monthly cycle?

ovary- grow follicle, secrete estrogen

uterus- shed lining, regenerate endometrium in response to increased estrogen

what are the phases of fertilization

1. Sperm penetration into the oocyte's corona radiata. 2. Sperm binding to the zona pellucida. 3. Fusion of sperm and oocyte membranes. 4. Completion of meiosis in the oocyte. 5. Formation of the zygote.

what hormone has an inhibitory effect on relaxin and estrogen?

progesterone

when do the first crossovers occur?

during fertilization when genetic material from mother and father mixes

where does fertilization occur?

in the ampulla of the oviduct

what is the zona pellucida

a layer surrounding the oocyte. sheds before fertilization.

what is a trophoblast

the outer layer of cells in a developing blastocyst. helps fertilization and forms placenta eventually

what is an embryoblast

aka inner cell mass. gives rise to all fetus tissues.

what is a cytotrophoblast

forms placenta

what is a syncytiotrophoblast

inplants in uterine wall and is responsible for establishing connection to maternal blood