Developmental Anatomy Flashcards

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?

First 28 days after birth. Signup and view all the answers

What is capacitation?

Sperm tails beat even faster to prepare their plasma membrane to fuse with the oocyte. Signup and view all the answers

What are corona radiata?

Granulosa cells left over from the follicle. Signup and view all the answers

What is the zona pellucida?

Clear glycoprotein layer between corona radiata and oocyte plasma membrane. Signup and view all the answers

What helps with penetration of sperm through these two layers?

Acrosomal enzymes. Signup and view all the answers

What is syngamy?

Process that blocks polyspermy. Signup and view all the answers

What is the fast block to polyspermy?

Oocyte cell membrane depolarizes so another sperm cannot fuse. Signup and view all the answers

What is the slow block to polyspermy?

Occurs as molecules released in fast block harden the zona pellucida. Signup and view all the answers

What happens when a sperm cell enters the oocyte and completes meiosis 2?

It divides into a larger ovum (mature egg) and a smaller second polar body that disintegrates. Signup and view all the answers

What do male and female pronuclei form when they fuse?

Produce a single diploid zygote. Signup and view all the answers

What indicates fertilization occurs?

Haploid sperm and haploid ovum merge to form a diploid zygote. Signup and view all the answers

What is cleavage?

Rapid mitotic division of zygote starting the first week of development. Signup and view all the answers

What are blastomeres?

Smaller cells produced by cleavage. Signup and view all the answers

What is the morula?

A solid ball of cells formed 3-4 days after fertilization. Signup and view all the answers

What is a blastocyst?

Hollow ball of cells that enters the uterine cavity. Signup and view all the answers

What is implantation?

Attachment of blastocyst to the endometrium 7-8 days after fertilization. Signup and view all the answers

What are the four extraembryonic membranes?

Chorion Signup and view all the answers

What is the embryonic disc?

Composed of cells that develop to become the fetus, visible as early as 3 weeks. Signup and view all the answers

What does the embryonic disc develop into?

Endoderm Signup and view all the answers

What does ectoderm differentiate into?

Tissues of the brain and nerves, epidermis of skin. Signup and view all the answers

What does mesoderm mature to form?

Connective tissue that matures to form blood, muscles, and bones. Signup and view all the answers

What does endoderm give rise to?

Epithelial lining of digestive, respiratory, and several other organs, smooth endothelial lining of vessels. Signup and view all the answers

What is the amnion?

Innermost 'bag of water' surrounding the amniotic cavity around the embryo. Signup and view all the answers

What is the yolk sac?

Site of early blood formation. Signup and view all the answers

What is the function of allantois?

Helps form the umbilical cord. Signup and view all the answers

What does chorion form?

Fetal portion of placenta and takes over production of hCG. Signup and view all the answers

What is the placenta?

Develops from mother and fetus; site of nutrient and waste management; prevents mixing of blood and takes over hormone secretion. Signup and view all the answers

What is the placenta formed from?

Chorionic villi (from embryo) and decidua basalis (from mother). Signup and view all the answers

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.
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.
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

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.