Anatomy - Embryology Of Limbs

Front 1

what are the names for the 3 sections of mesoderm that assemble in the embryo?

Back 1

paraxial mesoder, intermediate mesoderm, lateral plate mesoderm

Front 2

during development, cavities develop within the lateral plate mesoderm to form which two layers? Give 2 names for each

Back 2

parietal (somatic) and visceral (splachnic)

Front 3

what is the name for the original structures formed from the paraxial mesoderm?

Back 3

somitomeres

Front 4

how many somitomeres eventually become somites

Back 4

all but 7

Front 5

on which day of development does the first somite form?

Back 5

day 20

Front 6

by the 5th week of development, how many somites are present in the embryo?

Back 6

42-44

Front 7

in which direction do somites form in the developing embryo?

Back 7

cranial to caudal

Front 8

following their formation, somites differentiate into two parts. What are the names for these two parts?

Back 8

sclerotome and dermomyotome

Front 9

the sclerotome is derived from which part of the somite? What is the name for the sclerotome once it migrates toward the notochord?

Back 9

the core; mesenchyme

Front 10

the sclerotome that forms around the notochord becomes what? Around the neural tube?

Back 10

vertebral body; vertebral arch

Front 11

the dermomyotome separates into which layers?

Back 11

dermatome and myotome

Hint 11

None

Front 12

the dermatome spreads out and accounts form which aspect of the skin?

Back 12

dermis and hypodermis

Front 13

of what does the myotome consist? To what do these cells give rise?

Back 13

myoblasts; muscles of neck and trunk

Front 14

what is the fate for the myoblasts of the most ventrolateral aspect of the myotome?

Back 14

skeletal musle of the limbs

Front 15

into which two layers does the myotome further develop?

Back 15

epimere and hypomere

Front 16

to what does the epimere give rise? The hypomere?

Back 16

intrinsic (true) muscles; anterior and lateral trunk muscles

Front 17

what is the fate of the interemediate mesoderm?

Back 17

urogenital structures

Front 18

which portions of the body are formed from the splanchnic mesoderm (visceral)? The somatic (parietal) mesoderm

Back 18

structures associated with the respiratory and digestive systems; ventral and lateral portions of the body wall as well as the majority of the limb tissue

Front 19

limb buds become visible in the embryo at the end of which week?

Back 19

4th

Front 20

which appears first in the developing embryo, the upper or lower limb bud?

Back 20

upper

Front 21

what are the contents of the limb buds?

Back 21

ectoderm and mesenchyme

Front 22

the mesenchyme in the forming lumb buds is derived from where?

Back 22

the somatic layer of the lateral plate mesoderm

Front 23

what are the 3 demarcations of a limb bud?

Back 23

longitudinal axis, postaxial border, preaxial border

Front 24

at the tip of the ectoderm, the ectoderm thickens to form a ridge. What is the name for this ridge?

Back 24

apical ectoderm ridge (AER)

Front 25

what is the role of the AER?

Back 25

induce underlying mesenchyme to proliferate which causes the limb to grow

Front 26

what is the fate of the cells closest to the AER? Furthest?

Back 26

undifferentiated; differentiate into chondrocytes

Front 27

all the bones of the appendicular skeleton, with the exception of which one, form via endochondral ossification?

Back 27

clavicle

Front 28

development of the limb bud proceed in the distal to proximal or proximal to distal direction?

Back 28

proximal to distal

Front 29

the terminal portions of the limb buds are flattenen and form which two structures?

Back 29

hand plates and foot plates

Front 30

by what are the hand and foot plates separated from the rest of the limb bud?

Back 30

constrictions (wrist/ankle)

Front 31

what is the name for the precursors of the fingers and toes in the limb buds?

Back 31

digital rays

Front 32

myoblasts originate from which portion of the dermomyotome?

Back 32

ventrolateral

Front 33

as the epimere and the hypomere are forming, by what are they innervated?

Back 33

dorsal and ventral rami, respectively

Front 34

by what are the ventrolateral cells destined for the limbs innervated?

Back 34

ventral ramus

Front 35

the upper limb bud forms near which somites? The lower limb?

Back 35

C5-T1; L2-S3

Front 36

once in the limbs, how do the myoblasts organize themselves?

Back 36

dorsal and ventral condensations on either side of the developing bones

Front 37

what happens to VPR as it enters into limbs?

Back 37

separates into dorsal and ventral branches to supply muscles on anterior and posterior of the developing limb bones

Front 38

in the upper limb, the dorsal branches of the VPR eventually merge to form which two major nerves? The ventral merge to form which three major nerves?

Back 38

axillary and radial; musculocutaneous, median, and ulnar

Front 39

during which week of development do the developing limbs undergo horizontal flexion? This brings the limbs from which plane to which other plane?

Back 39

6th; coronal and sagittal

Front 40

what additional movement of the limbs occurs at the 7-8th week of development?

Back 40

rotation 90 degrees on longitudinal axis

Front 41

when the limbs rotate during the 7-8th week of development, in which direction do the upper limbs rotate? The lower limbs?

Back 41

laterally; medially

Front 42

in which direction does the thumb move during rotation of limbs? The big toe?

Back 42

laterally; medially

Front 43

what part of development of limbs during development distorts the dematome?

Back 43

limb rotation

Front 44

what is amelia? Meromelia? Phocomelia?

Back 44

absence of one or more limbs; absence of part of a limb; when proximal part of limb is shortened or absent (form of meromelia)

Front 45

what is a cleft hand or foot?

Back 45

when there is no middle ray and the first/second digits and fourth/fifth digits fuse

Front 46

what is polydactyly?

Back 46

excess digits on hand or foot

Front 47

what is syndactyly?

Back 47

fusion of digits due to incomplete cell death in the inter-ray space

Front 48

what is clubfoot?

Back 48

when the sole of the foot is turned inward and the foot if plantar flexed

Front 49

which kind of birth defect is associated with the breech position in the womb?

Back 49

congenital hip dislocation