Human Reproductive: Fetal Development And Embryology

A comprehensive set of flashcards covering key concepts related to human fetal development and embryology as presented in a lecture.

What is the first stage of zygote development called?

Cleavage.

How long does it take for the zygote to divide into two cells?

Usually up to 24 hours after fertilization.

What are the cells called that form during cleavage division?

Blastomeres.

At what stage does the conceptus begin expressing its own genes?

Early in the two-cell stage.

What is the solid ball of cells formed after cleavage called?

Morula.

What process allows the morula to become propelled down the Fallopian tube?

Ciliated epithelium movement.

When does the morula enter the uterus?

3 to 5 days after ovulation.

What is formed between the 32 to 64 cell stage?

Blastocyst.

How does the blastocyst obtain fluid during formation?

From secretions of endometrial glands.

What type of cells make up the outer layer of the blastocyst?

Trophoblast cells.

What is the inner cell mass of the blastocyst called?

Embryoblast.

What is the process by which the blastocyst attaches to the uterine wall?

Implantation.

What happens during the hatching of the blastocyst?

It digests a hole in the zona pellucida and squeezes through.

What must occur for successful implantation to happen?

The endometrial wall must be primed by hormones.

What type of implantation do humans undergo?

Invasive implantation.

What begins to develop on implantation of the blastocyst?

The placenta.

What are the three phases of nutrition acquisition for the embryo?

Absorption phase, histoplasmic transfer, hematotrophic phase.

What connects the fetus to the placenta during development?

Umbilical cord.

How long is the umbilical cord typically?

Approximately 55-60 cm.

At what week does the placenta fully develop its maternal blood supply?

By the end of the 1st trimester (week 14).

What is the embryo called after the 10th week of gestation?

Fetus.

What structures are formed by the 10th week of gestation?

All major structures.

During which trimester do sex organs begin to appear in the fetus?

Third month of gestation.

What critical development occurs around the end of week 5?

Electrical brain activity is first detected.

At what week do synapses begin to form in the fetus?

Week 17.

When can the mother typically feel the baby's movements?

Around the 20-21st week of gestation.

What is the first bowel movement of the fetus called?

Meconium.

What major growth occurs during the third trimester?

Rapid fetal growth.

What tissue is deposited during the last weeks of pregnancy?

Adipose tissue.

What developmental periods are involved in organogenesis?

Embryonic Period and Fetal Period.

From which stages do teratogens cause the most sensitivity?

During early embryonic development.

What is ectopic pregnancy?

Development of embryo or fetus outside of the uterine cavity.

What are potential problems for the mother with an ectopic pregnancy?

Bleeding, acute abdominal pain, rupture of uterine tube.

What is the significance of the trophoblast during implantation?

It digests the endometrium and facilitates attachment.

What happens to the blastocyst within an hour of contact with the uterine wall?

The stromal tissue of the endometrium is affected.

What must the blastocyst do to change the ovarian cyclic pattern?

Make effective contact with the maternal endocrine system.

What happens to the trophoblast after implantation?

It grows to form part of the chorion, an accessory fetal membrane.

What happens during the first phase of nutrition acquisition described?

Zygote is nourished by cellular cytoplasm and secretions.

By what week is the fetal development of organ systems almost complete?

By the end of the 6th month.

What functional ability begins to emerge around 30 weeks of gestation?

Minimal consciousness and ability to feel pain.

At what stage does the trophoblast stop nurturing the blastocyst?

After attachment; nursing shifts to uterine secretions.

What is the average size of a human placenta?

22 cm in length, 2-2.5 cm thickness.

What are the two types of implantation?

Invasive and non-invasive.

What physical change occurs to the fetus during the third trimester?

Majority of physical growth occurs.

What defines the end of the first trimester?

Completion of major organ structures.

What must happen to the endometrial tissue during implantation?

It must undergo vascularization and differentiation.