Gastrulation

Question 1

What is Gastrulation?

Answer 1

Gastrulation is an early developmental process in which an embryo transforms from a one-dimensional layer of epithelial cells, a blastula, and reorganizes into a multilayered and multidimensional structure called the gastrula.

Question 2

What is the role of estrogen in the follicular phase?

Answer 2

Estrogen acts synergistically with FSH to stimulate granulosa cell proliferation and expression of FSH receptors. High follicular levels of estrogen allow the granulosa cells to acquire more FSH receptors, and undergo cellular proliferation.

Question 3

True or False -

The corpus luteum produces progesterone for approx. 10-12 days to maintain the functional layers of the endometrium in preparation for fertilisation.

Answer 3

True

Question 4

What happens to the corpus luteum if fertilisation doesn’t occur?

Answer 4

The corpus luteum stops secreting progesterone, decays and turns into a corpus albicans. Without progesterone maintaining the endometrium, females shed the lining, resulting in menstruation.

Question 5

What is the luteinizing hormone/choriogonadotropin receptor (LHCGR)?

Answer 5

LHCGR is a transmembrane receptor found in the ovary and testis, but also many extragonadal organs such as the uterus and breasts. LHCGR is a GPCR-G-alpha-s and the pathway activated PKA.

Question 6

True or False -

Once activated LHCGR acts to up-regulate cholesterol side-chain cleavage enzyme (P450scc) activity leading to the conversion of cholesterol into androgen precursors required to make many steroid hormones.

Answer 6

True

Question 7

What is this structure?

Answer 7

Estradiol.

Question 8

What is this structure?

Answer 8

Estradiol.

Question 9

What is this structure?

Answer 9

Progesterone.

Question 10

What is this structure?

Answer 10

Progesterone.

Question 11

What is the role of Human placental lactogen?

Answer 11

Human placental lactogen (hPL) is a hormone released by the syncytiotrophoblast during pregnancy. It helps prepare your body for breastfeeding

Question 12

True or False -

hPL (human placental lactogen) acts similarly to hGH (human growth hormone) and has anti-insulin properties while facilitating the effects of glucagon.

Answer 12

True

Question 13

What is the function of cytotrophoblast?

Answer 13

Cytotrophoblast cells differentiate into villus cytotrophoblast cells that form finger-like projections into the maternal decidua. This helps the developing embryo attach to the wall of the uterus, protects the embryo, and forms a part of the placenta.

Question 14

True or False -

The epiblast is the organism.

Answer 14

True

Question 15

At what day is the extra-embryonic mesoderm present?

Answer 15

Day 8

Question 16

True or False -

At Day 12, the extra-embryonic mesoderm is divided into two layers: the extra-embryonic splanchnopleuric mesoderm, which lies adjacent to Heuser’s membrane around the outside of the primitive yolk sac; and the extra-embryonic somatopleuric mesoderm, which lies adjacent to the cytotrophoblast layer of the embryo.

Answer 16

True