Lecture 11 (Exam 2)

Question 1

The initial signaling for endoderm formation occurs during…

Answer 1

Gastrulation

Question 2

Signaling for endoderm formation depends on _______ expression during gastrulation.

Answer 2

Nodal

Question 3

Signaling for endoderm formation during gastrulation contains an anterior-posterior gradient. There are higher levels of nodal (ANTERIORLY/POSTERIORLY) and lower levels of nodal plus the presence of FGF-4 (ANTERIORLY/POSTERIORLY).

Answer 3

Anteriorly

Posteriorly

Question 4

The posterior gut expresses ______. This promotes hindgut development and suppresses formation of anterior gut structures.

Answer 4

Cdx-2

Question 5

The anterior gut expresses…

Answer 5

Hex
Sox-2
Foxa-2

Question 6

More refined differentiation of gut structures depends on _____ genes.

Answer 6

Hox

Question 7

In the anterior intestinal portal, there is an expression of…

Answer 7

Shh

Question 8

In the posterior intestinal portal, there is an expression of _____ followed by _____.

Answer 8

Shh

BMP-4

Question 9

Both the __________ membrane and ________ plate are formed by endoderm and ectoderm with no intervening mesoderm. Instability created by lack of mesoderm results in perforations of these plates.

Answer 9

Oropharyngeal (Oral plate)

Cloacal

Question 10

There are pockets created on the ectodermal sides of the oral and cloacal plates. The _________ is the future oral cavity, and the _________ is the future anal region.

Answer 10

Stomodeum

Proctodeum

Question 11

During this week of the embryo, the length is 4 mm. Rudiments for most of the major organ systems are present (except limbs and kidneys). There are prominent pharyngeal arches and a Wolffian ridge.

Answer 11

4th week

Question 12

This extraembyronic tissue is part of the inner cell mass and an epiblast derivative.

Answer 12

Amnion

Question 13

This extraembryonic tissue is part of the inner cell mass and a hypoblast derivative.

Answer 13

Yolk sac

Question 14

These extraembryonic tissues are part of the fetal maternal interface and are trophoblast derivatives.

Answer 14

Chorion

Placenta

Question 15

This extraembryonic tissue is part of the inner cell mass and interfaces with placenta via the umbilical cord.

Answer 15

Allantois

Question 16

The function of this extraembryonic tissue to accommodate growth, allow normal movements, buffer against mechanical injury, and protect the fetus from adhesions.

Answer 16

Amnion

Question 17

What is the normal amount of amniotic fluid at term?

Answer 17

500-1000 mL

Question 18

This is the term for an excess amount of amniotic fluid (>2000 mL). It is related to multiple pregnancies, esophageal atresia (swallowing defects), and anencephaly (head defects).

Answer 18

Hydramnios

Question 19

This is the term for too little amniotic fluid (<500 mL). It is related to renal agenesis (absence of kidneys) and shows the importance of fetal urine contributions.

Answer 19

Oligohydramnios

Question 20

In phase I of the formation of amniotic fluid –

• First _____ weeks of pregnancy
• Free diffusion of _______ through fetal ectoderm
• Maternal serum
• Secretion by amniotic membrane

Answer 20

20

Electrolytes

Question 21

In phase II of the formation of amniotic fluid –

• Contributions from fetal ______
• Filtration from vessels associated with _____ _____

Answer 21

Urine

Chorion laevae

Question 22

What nutrients are concentrated in the yolk sac?

Answer 22

Folic acid
Vitamin A
Vitamin B12
Vitamin E

Question 23

This is the term used for when nutrients are concentrated in the yolk sac and absorbed by endocytosis before the placental circulation is established.

Answer 23

Histiotrophic nutrition

Question 24

The yolk sac is also the site of origin of ______ ______ cells and is the location of ______ ______, which are the origin of initial blood cells (extraembryonic hematopoiesis).

Answer 24

Primordial germ

Blood islands

Question 25

In a small percentage of adults, they contain traces of the yolk duct as a fibrous cord or outpouching of the small intestine. This is called...

Answer 25

Meckel's diverticulum

Question 26

The allantoic (_______) vessels develop in the mesoderm of the allantois.

Answer 26

Umbilical

Question 27

The proximal part of the allantois is called the _______. It is associated with the formation of the urinary bladder and becomes the _______ _______ ligament.

Answer 27

Urachus | Median umbilical

Question 28

In this stage of placental development, there are no villi formed on the trophoblast.

Answer 28

Previllous embryo

Question 29

In this stage of placental development, solid, cytotrophoblastic, ectodermal primary villi appear.

Answer 29

Primary villous stage

Question 30

In this stage of placental development, the mesodermal core appears within the primary villi.

Answer 30

Secondary villous stage

Question 31

In this stage of placental development, it is characterized by the appearance of blood vessels within the mesenchymal core of the secondary villi.

Answer 31

Tertiary villous stage

Question 32

In the final stages in development of the placenta, there are cytotrophoblastic (SHELLS/COLUMNS) which go on to expand over the maternal decidual cells and form cytotrophoblastic (SHELLS/COLUMNS).

Answer 32

Columns | Shells

Question 33

In the final stages in development of the placenta, there are ________ villi which are anchored to the cytotrophoblastic shell (as opposed to floating villi).

Answer 33

Anchoring

Question 34

In the maternal blood flow pathway, the maternal blood enters intervillous spaces, called ________ _______, from _______ arteries.

Answer 34

Trophoblastic lacunae | Spiral

Question 35

In the maternal blood flow pathway, there is an exchange of materials (respiratory gasses, nutrients, waste products) between maternal blood in lacunae and fetal blood in ________ in the villi.

Answer 35

Capillaries

Question 36

In the maternal blood flow pathway, the maternal blood returns to maternal veins in the _______ _______.

Answer 36

Decidua basalis

Question 37

In the fetal blood flow pathway, fetal blood is entirely enclosed within _______.

Answer 37

Vessels

Question 38

In the fetal blood flow pathway, fetal blood travels to capillary beds within placental villi via ________ arteries (usually two).

Answer 38

Umbilical

Question 39

In the fetal blood flow pathway, fetal blood returns from capillary beds within placental villi via ________ vein (usually one).

Answer 39

Umbilical

Question 40

In the maternal-fetal blood flow pattern, there is usually (ONE/TWO) umbilical artery(ies), and (ONE/TWO) umbilical vein(s).

Answer 40

Two | One