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49 Cards in this Set
- Front
- Back
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What does the epiblast differentiate into?
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Ectoderm
Mesoderm |
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Where do primordal germ cells form in the embryo?
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Posterior epiblast
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What is the name of the gene that cases development of primordal germ cells into spermatogoonia?
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SRY
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What is the function of the SRY gene?
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Development of primordial germ cells into spermatogoonia
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What phase of meiosis are oocytes stuck into until fertilization?
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Prophase II
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What cells give rise to teratomas? Why?
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Primordial germ cells
Don't stay isolated from growth factors outside the gonadal ridge |
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Where is the glycoprotein coat added inside the testes in spermatogenesis?
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The epididymis
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What is the function of the acrosome?
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Release digestive enzymes for entry into the egg
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What is the stimuli for release of the eggs into the fallopian tube/development of the follicle?
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LH surge
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What is the are of cells surrounding the egg called?
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Corona radiata
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What is the structure/function of the zona pellucida?
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Glycoprotein coat
Provide a way for sperm to bind to the egg |
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When does the egg form polar bodies?
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1st: before birth; cells are arrested in prophase 1
2nd: after fertilization |
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Where in the fallopian tube are eggs normally fertilized?
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Ampulla
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What is the molecular cue for the navigation of sperm to the egg? What mechanism is used in the sperm?
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Progesterone
Calcium influx |
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Upon entry to the uterus, what process is essential in sperm for successful fertilization?
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Capacitation
Shedding of the glycoprotein coat |
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What are the functions of ZP3?
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Binding to the zona pellucida
Penetrating the zona pellucida Block to polyspermy Species specificity |
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What proteins on the zona pellucida are essential for the binding of sperm?
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ZP1 - 3
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What is the mechanism by which polyspermy is blocked?
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1. Binding of sperm ZP3 receptor to ZP3
2. Breakage of acrosome, penetration of the egg 3. Binding of sperm to PM causes Ca2+ release, causing hydration and a block to polyspermy |
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After meisois II happens in the fertilized egg, what transient event occurs? In what scenario is this important?
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Formation of male/female pronuclei
When using assisted reproductive technologies, you need to check for this to ensure that polyspermy did not occur |
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What are the broad classes of fertilization age?
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Early development: 0-3 weeks
Embryonic period: 3-8 weeks Fetal period: 8 weeks-term |
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What is the sequence of events in week one of the fertilized egg?
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Day 1: Fertilization
Day 2-3: Cleavage Day 3: Compaction Day 4: Formation of blastocyst Day 5-6 Attachment to endometrium |
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What are the individual cells of the embryo called?
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Blastomeres
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What are blastomeres?
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Individual cells of the embryo
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During the first week of life, does the baby increase in size?
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No!
The ball of cells stays the same size, but cytoplasm is put in smaller and smaller compartments |
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What protein is required for compaction?
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E-cadherin
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What are the two different cell populations that are formed by compaction?
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Compacted cells: inner cell mass --> embryo
Outside cells --> trophoblast --> placenta |
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What is the structure of the blastocyst?
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Round, mostly hollow ball of cells.
Outside = trophoblast Inside = inner cell mass Cavity: blastocoele |
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What is the blastocoele
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The fluid inside of the blastocyst; a cavity
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What is the mechanism of formation of the blastocoele?
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Pumping of sodium into the blastocyst, and water follows
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When in development does monozygotic twinning occur?
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During cleavage/blastocyst
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How and why does the blastocyst escape from the zona pellucida?
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The trophoblasts secrete proteases
This happens due to the fact new zona pellucida isn't synthesized anymore If this doesn't happen correctly, you can get infertility or ectopic pregnancy |
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What protein functions in attachment of the embryo to the endometrium?
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L Selectin
Not E-cadherin, which is responsible for compaction of the embryo |
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What is the function of L selectin?
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Attachment of the embryo to the endometrium
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Where is L-selectin expressed?
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On the trophectoderm
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What is the main focus of week two of embryonic development?
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Implantation of the embryo
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What types of cells are extremely invasive and attach to the endometrium?
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Trophectoderm
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What is the second lineage decision made by the early embryo? What week does this occur during?
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Epiblast vs. primitive endoderm
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What two proteins are essential in the second lineage decision?
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Epiblast: Nanog
Primitive endoderm: Gata6 |
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In what tissue is Gata6 expressed?
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Primitive endoderm
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In what tissues is Nanog expressed?
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Epiblast
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What is the function of Nanog?
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Differntiation of the epiblast
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What is the function of Gata6?
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Differentiation of the primitive endoderm
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What energy stores do the trophoblasts tap into?
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Maternal blood
Glycogen stored inside the maternal glands |
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What is the cytotrophoblast?
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A stem cell population in the trophoblast layer
Gives rise to the syncitiotrophoblast |
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What is the syncytiotrophoblast?
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The invasive cell population that goes into the endometrial wall
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What two structures does the embryo differentiate into in week 2?
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Hypoblast: extraembryonic structures
Epiblast: Embryo itself |
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What two cavities are in the embryo at week 2?
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Amniotic cavity
Yolk sac cavity |
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What type of tissue migrates into the endometrium to form blood vessels?
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Mesenchyme
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Where are two bad places for pregnancy to take place?
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Tube
Ovary |
