Exam 1 human embryology

Where does fertilization occur?

Ampulla of the oviduct

What is the role of progesterone after ovulation?

To prepare the uterine lining for implantation.

What is the purpose of compaction during cleavage?

To develop inside-outside polarity and maximize cell signaling.

At which stage does the embryo undergo compaction?

8-cell stage

What is the primary role of Zygotic Genome Activation (ZGA) in early embryonic development?

To switch control from maternal RNAs to the embryo's own genome.

Which transcription factors are critical for maintaining pluripotency in the inner cell mass (ICM)

Oct4, Sox2, Nanog

What is the primary function of the trophoblast cells

To form the placenta

What is the difference between totipotent and pluripotent cells?

Totipotent cells can form all tissues, including the placenta, while pluripotent cells can only form embryonic tissues.

What is the purpose of iPSC generation?

To reprogram somatic cells into pluripotent stem cells.

What is the role of hCG during implantation?

To maintain the corpus luteum and support progesterone production.

What happens if implantation does not occur?

Progesterone levels drop, leading to menstruation.

What are the two layers formed from the inner cell mass (ICM) during the second week?

Epiblast and Hypoblast

What does epiblast give rise to?

Future embryo and amniotic sac

What is the main function of the amniotic cavity during early development?

To cushion and protect the embryo

The amniotic fluid primarily functions to

Protect the embryo from physical shock

Which trophoblast layer is responsible for invading the uterine lining and producing hCG

Syncytiotrophoblast

What is the role of hCG during implantation

Stimulates the corpus luteum to produce progesterone

The extraembryonic mesoderm (EM) contributes to the formation of which cavity

Chorionic cavity

The yolk sac is primarily responsible for

Early blood formation and nourishment

The primary yolk sac is formed by

Hypoblast migration and the formation of extraembryonic mesoderm

The defintive yolk sac is formed when

The primary yolk sac detaches and degenerates

Which structures contribute to the formation of the uteroplacental circulation?

Primary villi, secondary villi, tertiary villi.

What is the primary function of the uteroplacental cirulation?

To exchange gases, nutrients, and wastes between maternal and fetal blood

Which of the following structures does the ectoderm give rise to?

Skin and nervous system

The mesodermal gives rise to all of the following EXCEPT

Digestive system

Which of the following describes ingestion during gastrulation?

Movement of epic last cells inward to form mesodermal and endoderm.

The notochord plays an important role in

Inducing neural tube formation

Sonic Hedgehog (Shh) is secreted by which structure during the formation of the notocord?

Notochord

Neural induction refers to

The signaling process that induces ectodermal cells to form the neural plate

Neural crest cells give rise to all of the following EXCEPT

Spinal Cord

The definitive endoderm gives rise to

Digestive system and internal organs

The formation of definitive endoderm involves which process

Ingestion of dpi last cells that displace the hypoblast

The intraembryonic mesoderm gives rise to all of the following EXECPT

Digestive system

The paraxial mesoderm develops into which of the following?

Muscles and bones

The prechordal plate contributes to the development of which structure

Oral cavity and forebrain

The anterior visceral endoderm (AVE) is essential for the formation of which region of the body?

Head and face

The primitive node serves as an organizer by

Inducing neural tube formation
Regulating body axis formation
Stimulating mesodermal differentiation

Ingestion during gastrulation involves

Cells moving inward to form mesoderm and endoderm

The left-right axis is established by

The primitive node and nodal signaling

Neurulation involves the formation of which structure

Neural tube

Which signaling molecule is secreted by the notochord to pattern the ventral neural tube?

Sonic Hedgehog (Shh)

Somites develop into all of the following EXCEPT

Blood vessels

Which of the following signaling pathways regulates so mite segmentation?

Notch signaling

The cardiac crescent i derived from which mesodermal region?

Cardiogenic mesoderm

Which transcription factor is critical for heart formation?

Nkx2.5

The pharyngeal arches contribute to the development of all the following expect

Heart valves

Which signaling molecule is involved in the development of pharyngeal arches?

Fgf8

Cranio-caudal and lateral folding transforms the embryo from:

A flask disc to a 3D tube

The septum transversum forms and separates which two cavities?

Thoracic and abdominal cavities

Neural crest cells contribute to all of the following EXPECT

Epithelial cells of the skin

What signaling molecule plays a role in the migration and differentiation of neural crest cells?

Wnt

Which of the following best describes Hox gene function in segmental identity?

They control anterior-posterior segmental identity