Embryogenesis & Development Flashcards
The widest part of the fallopian tube where fertilization occurs is known as ?
Ampulla
What occurs after the penetration of sperm through the cell membrane ?
Cortical rxn (release of Ca2+ ions) -Depolarizes membrane of the ovum to prevent fertilization of ovum by multiple sperm & high Ca2+ increases metabolic rate of zygote
The fertilization of 2 different eggs by 2 different sperm results in what ?
Dizygotic (fraternal) twins
- Each develop its own structures & components
- No more genetically similar than regular siblings
What is the result of a single zygote splitting into 2 ?
Monozygotic (identical) twins
What is the difference between indeterminate & determinate cleavage ?
Indeterminate results in cells that can still develop into complete organisms, while determinate results in cells that are committed to differentiating into certain types of cells
What does the embryo become after several rounds of division (cleavage) ?
Morula (solid mass of cells)
A morula undergoes blastulation, which form the blastula…what is a blastula ?
Hollow ball of cells w/ fluid filled inner cavity (blastocoel)
- mammalian blastula = blastocyst (consists of trophoblast & inner cell mass)
- trophoblast: surrounds blastocoel & gives rise to chorion & placenta
- inner cell mass: protrudes into blastocoel & gives rise to the organism
The extraembryonic membrane that later develops into the placenta is known as ?
Chorion
What structure supports the embryo before functional placenta development, & serves as a site for early blood cell development ?
Yolk sac
What is the difference between the 2 embryonic membranes: allantois & amnion ?
Allantois is involved in fluid exchange btwn. yolk sac & embryo
Amnion surrounds the allantois (filled w/ amniotic fluid); serves as a shock absorber during pregnancy
What does the process of gastulation encompass ?
Gastrula: a small invagination in the blastula
invagination is known as archenteron, and opening is known as blastopore
What’s the difference btwn deuterostomes & protostomes ?
D: blastopore develops into anus
P: blastopore develops into mouth
What all does the ectoderm encompass ?
Integument
Lens of eye
Nervous system (including adrenal medulla)
Inner ear
What all does the mesoderm encompass ?
Musculoskeletal, circulatory, & excretory system
Gonads
Muscular & connective tissue
What all does the endoderm encompass ?
epithelial linings