FOM 6.4.1

Question 1

What are the three mesoderm derivatives?

Answer 1

Paraxial (dorsal), intermediate, and lateral plate (ventral)

Question 2

What is the appearance of the paraxial mesoderm and its location?

Answer 2

It is the thicken medial portion on either side of the notochord (at day 17-19)

Question 3

Describe the locations of the three derivatives of the mesoderm.

Answer 3

Look at picture

Question 4

What are the two portions of the lateral plate mesoderm?

Answer 4

Somatic (parietal) and Splanchnic (visceral)

Question 5

What the important bodily derivatives of the the paraxial, intermediate, and lateral plate mesoderm?

Answer 5

Paraxial: vertebrae and ribs, dermis of dorsal, skeletal muscle Intermediate: urogenital structures Lateral Plate: heart, blood vessels, smoot muscle, and body wall

Question 6

What is the precursor of somites? When are both formed in the embryo?

Answer 6

Somitomeres (~day 15), somites (~day 20)

Question 7

What can somites be used for clinically during the early development of the embryo?

Answer 7

Staging

Question 8

What are three different lineages of somites? Their associated structures?

Answer 8

Sclerotome (hard): ribs, vertebrae, rib cartilage Myotome (muscle): muscles of the back, body wall and some limb muscles Dermatome: dermis of the back

Question 9

What is the subset of somites that form most of the musculature for the body wall (obliques, transverse abdominus) and limbs

Answer 9

Ventrolateral cells

Question 10

Describe the stages of development of the somites in the fourth wk.

Answer 10

2 pics.

Question 11

How are the somatic genes regulated during differentiation?

Answer 11

Integrated signaling of signaling molecule concentraitons

Question 12

Which embryonic layers contribute to the pharyngeal arches? What is the purpose of these arches?

Answer 12

All three layers ;) They contribute to the formation of the face, neck, mouth, larynx, pharnyx

Question 13

What are the main structures that are derived from the intermediate mesoderm?

Answer 13

Urogential structures (kidneys, gonads, and their duct systems)

Question 14

How many overlapping kidney systems exist within the embryo? Which of the kidney systems leads to the formation of the adult kidney?

Answer 14

3; metanephric

Question 15

Primordial germ cells migrate from the wall of the yolk sac to the where? They ultimately induce the formation of the gonads from this location.

Answer 15

(Uro)genital ridges (IM)

Question 16

REPEAT! YOU BETTER KNOW THIS: What are the two layers of the intraembryonic body cavity of the lateral plate mesoderm?

Answer 16

1) Somatic/parietal 2) Splanchic/visceral

Question 17

Be as specific as possible. What gives rise to the heart?

Answer 17

Lateral plate (splanchnic) mesoderm

Question 18

Aside from the heart, what are the main derivatives of the lateral plate (splanchnic) mesoderm?

Answer 18

Blood vessels and blood cells

Question 19

Describe the different locations of hematopoiesis as the embryo develops.

Answer 19

1) extraembryonic (blood islands) - 3 wks 2) AGM: aorta-gonad-mesonephros 3) Liver - 2-7 months 4) Bone Marrow - 7 months

Question 20

Later in development (5-8 wks), how is development staged?

Answer 20

Crown-rump length

Question 21

Describe the composition of the limb buds (2 layers).

Answer 21

1) mesenchymal core (parietal/somatic LPM) 2) cuboidal ectoderm covering

Question 22

Apoptosis of what region leads to digit formation?

Answer 22

Apical ectodermal ridge

Question 23

Distinguish b/t blood vessel formation via angiogenesis and vasculogenesis.

Answer 23