EMBRYO

Question 1

what are the 3 main axes of coordination?

Answer 1

proximal-distal: AER

anterior-posterior: ZPA

dorsal-ventral: ectoderm

Question 2

High concentration of morphogens in ZPA

Answer 2

5th digit and posterior structures

Question 3

Low concentration of morphogens in ZPA

Answer 3

2nd digit and anterior structures

Question 4

No morphogens (No concentration)

Answer 4

1st digit and anterior

Question 5

what defines the mesoderm?

Answer 5

paraxial
intermediate
VLPM
PLPM

Question 6

the paraxial mesoderm produces what?

Answer 6

axial skeleton

all skeletal muscle

Question 7

the intermediate mesoderm produces what?

Answer 7

urinary system

reproductive system

Question 8

VLPM of the mesoderm produces?

Answer 8

cardiovascular system

GI/resp tract lining and smooth muscle

Question 9

PLPM of the mesoderm produces?

Answer 9

appendicular skeleton

Question 10

what are the layers of the paraxial mesoderm?

Answer 10

sclerotome
dermomyotome
-myotome
--epimere (body wall)
--hypomere (back muscles)
-dermotome

Question 11

in the 4th week, what are visible?

Answer 11

limb buds

Question 12

when are the limbs formed?

Answer 12

by the 8th week

Question 13

what induces adjacent mesoderm to continue to proliferate and
remain undifferentiated in proximal-distal limb axis (aka proximal zone)

Answer 13

AER

Question 14

specific

ectodermal specializations

Answer 14

Mesoderm begins differentiation once AER has migrated past it
🡪induces formation of limb

Question 15

caudal orientation

differentiation

Answer 15

Retinoic acid from cells of zone of polarizing activity (ZPA) directs cranial

Question 16

Retinoic acid highest for which digit?

Answer 16

thumb

Question 17

Upper limbs will be profused by the _____?

Answer 17

the median artery

*replaced by radial and ulnar arteries

Question 18

lower limbs are professed by _____?

Answer 18

Umbilical artery -> Axis Artery > perfusion of lower limb

Question 19

Adult pattern of arterial supply is reached by:

Answer 19

8th Intrauterine

week

Question 20

arterial supply for lower limb?

Answer 20

femoral artery

axis artery

Question 21

extension of new EXTERNAL ILIAC ARTERY

Answer 21

Femoral Artery

Question 22

starts as capillary plexus from the UMBILICAL ARTERY

Answer 22

Axis Artery

Question 23

important genes expressed at the LPM prior to limb growth?

Answer 23

Tbx-5 cranially and Tbx-4 caudally

Question 24

name this gene expressed at the LPM?

expression therefore causes the limb bud to form into an arm

Answer 24

Tbx-5

Question 25

name this gene expressed at the LPM?

region will form a leg

Answer 25

Tbx-4