EMBRYOLOGY 1ST WEEK

Question 1

The study of the origin and development of an organism. Begins with the fertilization of an oocyte by a sperm creating a zygote. This begins the human developmental pathway

Answer 1

Embryology

Question 2

Before Birth

Answer 2

Prenatal period

Question 3

Prenatal period is how many weeks?

Answer 3

38 weeks from conception, 40 weeks gestational age

Question 4

When all major organs formed?

Answer 4

Embryonic period, or called the embryogenesis or organogenesis

Question 5

The Fetal Period

Answer 5

Remaining 30 weeks, organs grow larger and more complex

Question 6

How are early development described?

Answer 6

In stages from Fertilization

Question 7

Stage 1 is..

Answer 7

Fertilization

Question 8

Embryonic stage ends at

Answer 8

stage 23 (day 56)

Question 9

Differentiated

Answer 9

When the cell becomes more specialized and have differentiated into a mature cell type

Question 10

Morphogenesis

Answer 10

Formation of shape during development. Cells can change how they adhere to one another, can change their shape, migrate to new locations.

Question 11

Dysmorphogenesis

Answer 11

Abnormal development…may occur due to malformation or deformation.

Question 12

Signaling is when

Answer 12

one group of cells influences the development of another group of cells near or far

Question 13

Signaling in the Embryo

Answer 13

Signalling of a vast array of different proteins by different cells allows those cells to gain information about current or future tasks

Question 14

Paracrine Signaling

Answer 14

Act by signaling transduction pathways directly or by blocking the activity of an inhibitor

Question 15

What are the four groups of Paracrine signaling proteins?

Answer 15

Wnt
Hedgehog
Fibroblast Growth Factor (FGF)
Transforming Growth Factor (TGT-B)

Question 16

The Paracrine signaling protein Wnt

Answer 16

They are proteins which are a version of the wingless gene because mutating the gene caused flies to develop without wings.

Question 17

Failure of the Wnt signaling protein causes?

Answer 17

Result in limb, eye, genitourinary and bone development disorders. Can be inhibited by sFrps which stop the signaling.

Question 18

The Hedgehogs proteins are similar to?

Answer 18

Works like a skeleton key and can open a lot of different doors. the cell effect depends on type dosage and deferential of the cell

Question 19

The Hedgehog proteins was first identified and resulted in?

Answer 19

Identified in Drosophila in the early mutation of the embryo. Gives the embryo the hedgehog like appearance and results in embryo being shorter.

Question 20

The three Hedgehogs in humans?

Answer 20

1) Sonic hedgehog homologue (SHH)-
2) Indian Hedgehog (IHH)-
3) Desert Hedgehog (DHH)-

Question 21

Sonic Hedgehogs protein is involved in?

Answer 21

Involved in neural, bone, limb, and kidney development plus muscle and lung. Also involved in the special sense organs. Binds to a cell transmembrane called Patched.

Question 22

How many FGF’s are there?

Answer 22

22 varieties. In embryological development they are involved in limb and neural dev, angiogenesis, very early patterning and induction of mesoderm development

Question 23

FGF receptors are part of?

Answer 23

the signaling transduction process. Interference with these effects causes a number of developmental abnormalities.

Question 24

TGF-B is described as?

Answer 24

Part of the super family of signaling and includes the bone morphogenetic proteins (BMPs). Was thought to be tumor related but later identified in other events during embryological dev

Question 25

How many forms of TGF-B and types of BMP’s discovered?

Answer 25

3 TGF-B and 15 types of BMP’s

Question 26

TGF-B ligands bind and change what?

Answer 26

Bind to a type II TGF-B receptor and recruits a type I receptor and ultimately change DNA transcription

Question 27

Juxtacrine Signaling

Answer 27

Occurs btw adjacent cells or btw a cell and the extracellular matrix…the direct contact affects the neural system and the heart along with other developmental areas.

Question 28

Notch Gene

Answer 28

Discovered in Drosophila, it is populations known to help maintain stem cell also development in specific cell clusters such as neurone, endothelial, cardiocyte and T cell development to name a few

Question 29

Interruptions to signaling in any way, be it proliferation, migration…can cause

Answer 29

Congenital abnormalities

Question 30

If thalidomide is taken during embryo stage (3-8 wks)

Answer 30

Can cause phocomelia which is the shortening of the limbs