Questions and Answers
What is developmental biology?
Study of sequence of events from fertilization of ovum by sperm to formation of adult.
What is the embryonic period?
Fertilization - 8 weeks.
What is the fetal period?
9 weeks - birth.
What is the neonatal period?
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What is capacitation?
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What are corona radiata?
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What is the zona pellucida?
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What helps with penetration of sperm through these two layers?
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What is syngamy?
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What is the fast block to polyspermy?
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What is the slow block to polyspermy?
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What happens when a sperm cell enters the oocyte and completes meiosis 2?
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What do male and female pronuclei form when they fuse?
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What indicates fertilization occurs?
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What is cleavage?
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What are blastomeres?
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What is the morula?
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What is a blastocyst?
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What is implantation?
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What are the four extraembryonic membranes?
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What is the embryonic disc?
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What does the embryonic disc develop into?
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What does ectoderm differentiate into?
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What does mesoderm mature to form?
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What does endoderm give rise to?
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What is the amnion?
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What is the yolk sac?
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What is the function of allantois?
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What does chorion form?
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What is the placenta?
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What is the placenta formed from?
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Study Notes
Developmental Biology
- Focuses on the sequence of events from fertilization to the formation of an adult organism.
Embryonic and Fetal Periods
- Embryonic Period: Lasts from fertilization to 8 weeks post-fertilization.
- Fetal Period: Spans from 9 weeks until birth.
Neonatal and Capacitation Stages
- Neonatal Period: The first 28 days following birth.
- Capacitation: Process where sperm tails beat faster, preparing for fusion with the oocyte.
Oocyte Structure
- Corona Radiata: Layer of granulosa cells surrounding the oocyte.
- Zona Pellucida: Clear glycoprotein layer located between the corona radiata and the oocyte plasma membrane.
Sperm Penetration
- Acrosomal Enzymes: Aid in penetrating the corona radiata and zona pellucida.
Syngamy and Polyspermy
- Syngamy: Mechanism that blocks polyspermy (fertilization by multiple sperm).
- Fast Block to Polyspermy: Membrane depolarization of the oocyte preventing further sperm fusion.
- Slow Block to Polyspermy: Hardening of the zona pellucida triggered by substances released during the fast block process.
Fertilization Process
- Occurs when the haploid sperm and ovum merge to form a diploid zygote.
- Meiosis Completion: Entry of sperm into the oocyte completes its Meiosis II, producing a larger ovum and a smaller polar body.
Early Development Stages
- Cleavage: Rapid mitotic divisions of the zygote beginning shortly after fertilization.
- Blastomeres: Smaller cells formed from cleavage.
- Morula: A solid ball of cells formed 3-4 days post-fertilization.
- Blastocyst: A hollow ball of cells that enters the uterine cavity.
Implantation and Extraembryonic Membranes
- Implantation: Occurs 7-8 days after fertilization when the blastocyst attaches to the endometrium.
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Extraembryonic Membranes:
- Amnion: Surrounds the embryo as the innermost membrane.
- Yolk Sac: Early site of blood formation.
- Allantois: Contributes to umbilical cord formation.
- Chorion: Forms the fetal part of the placenta and produces hCG.
Embryonic Development
- Embryonic Disc: Composed of cells that will develop into the fetus, visible from 3 weeks after fertilization.
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Germ Layers:
- Ectoderm: Develops into the brain, nerves, and skin epidermis.
- Mesoderm: Forms various connective tissues, blood, muscles, and bones.
- Endoderm: Gives rise to epithelial linings of organs and blood vessels.
Placenta Functions and Formation
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Placenta: Develops from both maternal and fetal tissues.
- Manages nutrient and waste exchange.
- Prevents mixing of maternal and fetal blood.
- Takes over hormone production and prepares mammary glands for lactation.
- Formation: From chorionic villi (fetal) and decidua basalis (maternal).
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Test your knowledge of developmental anatomy with these flashcards. Covering terms like developmental biology, embryonic and fetal periods, and more, this quiz is designed to reinforce key concepts in developmental biology. Perfect for students and anatomy enthusiasts.