embryology

Question 1

vertebral anomalies

Answer 1

formation failure, segmentation failure, mixture of both

Question 2

what forms vertebral bodies

Answer 2

sclerotomes, that migrate ventromedial on each side of the notochord. vertebral bodies are formed from cranial and caudal sclerotomes

Question 3

somites

Answer 3

42-44 pairs formed by the union of mesoderm cells

Question 4

somites give rise to ____, ____, and ____, at what week?

Answer 4

sclerotomes, myotomes, dermatomes, 4th week

Question 5

notochord is formed by what cells

Answer 5

mesoderm cells

Question 6

nucleus pulposus is formed by…

Answer 6

remnants of the degenerated notochord

Question 7

annulus fibrosis orginates from what cells?

Answer 7

sclerotome cells

Question 8

vertebral formation defects

Answer 8

absence of a structural vertebral element resulting in a misshaped vertebra. caused by inadequate blood supply to vertebral bodies

Question 9

typed of vertebral formation defects

Answer 9

wedged vertebra, hemi-vertebra

Question 10

wedged vertebra

Answer 10

unilateral partial failure of vertebral formation

Question 11

hem-vertebra

Answer 11

half of the vertebra is absent

Question 12

results of vertebral formation defects (dx)

Answer 12

genetic scoliosis, torticollis

Question 13

vertebral segmentation defects

Answer 13

failure of sclerotome segmentation. vertebra don’t separate properly and produce a bar w/ no growth plate or disk btwn vertebra. can result in scoliosis

Question 14

congenital spinal deformities

Answer 14

failure of normal vertebral formation in 4th-6th week of gestation. location of anomaly determines the deformity. in cervical region=torticollis, lateral=scoliosis, anterior=kyphosis.

Question 15

congenital scoliosis

Answer 15

can dx w/ fetal US. may be diagnosed simultaneously with plagiocephally or torticollis. signs are patch of hair, midline skin hemangioma, congenital heart defects, kidney defects, LLD.

Question 16

causes of spinal malformation

Answer 16

neural tube defects, vertebral formation failure, segmentation failure.

Question 17

klippel-Feil syndrome

Answer 17

congenital fusion of 2 or more cervical vertebra/segmentation failure.

Question 18

classic clinical triad of Klippel-Feil syndrome

Answer 18

low posterior hairline, short neck, cervical ROM limitation in 40-50% of pts. ROM usually limited in lateral bending and rotation.

Question 19

VACTERL

Answer 19

acronym for syndromes that may co-exist with congenital spinal deformities. =vertebral anomalies, anal atresia, cardiac defects, tracheal anomalies, esophageal atresia, renal syndromes/problems, limb abnormalities.

Question 20

% frequency of the presence of congenital heart defects with congenital spine defects

Answer 20

30%

Question 21

congenital heart defects seen with congenital spinal deformities and why

Answer 21

b/c of the common origin of mesoderm. atrial or ventral septal defects. patent ductus arteriosus., tetralogy of Fallot, chest wall deformities (may present with rib fusion)

Question 22

skull development is different in what was from other boney formations?

Answer 22

it does not develop out of endochondral ossification like long bones

Question 23

skull development is derived from what cells?

Answer 23

mesenchymal cells derived from the neural crest and mesoderm cells

Question 24

skull development is by what process

Answer 24

interosseous ossification-intramembranous ossification: mesenchyme cells differentiate directly into the osteocytes without forming the hyaline cartilage model

Question 25

what is established during weeks 4-8 weeks of embryonic period?

Answer 25

all major external and internal structures are established. this organogenetic period starts development of all the major organ systems. teratogen from 4-8 weeks may cause major congenital anomalies.

Question 26

teratogen

Answer 26

any agent affecting fetal development (birth defects).

Question 27

vulnerability of fetus to teratogens is dependent upon

Answer 27

timing when cellular differentiation and morphogenesis is at its peak. magnitude, duration of exposure, ability to cross the placenta barrier.

Question 28

teratogen examples-STORCH

Answer 28

alcohol and drugs and STORCH-acronym for infections that can be passed to the fetus: syphillis, toxoplasmosis, other (HIV), rubella, cytomegalovirus, herpes.

Question 29

FAS

Answer 29

fetal alcohol syndrom. #1 cause of cognitive impairments. frontal lob disorder. comprises 10-20% of all cases of mental retardation. small size in weight and height, poor coordination, ADD/ADHD, poor memory, poor reasoning and judgement, sleep and sucking problems as a baby-failure to thrive, vision and hearing problems, heart, kidney, bone problems, hypotonia, learning disability, speech and language delay.

Question 30

pre-embryonic stage

Answer 30

1st 3 weeks. fertilization and implantation and formation of the placenta.

Question 31

embryonic stage

Answer 31

weeks 3-8. organogenesis period. very vulnerable to teratogens.

Question 32

ogranogensis

Answer 32

formation of the organ systems

Question 33

fetal period

Answer 33

weeks 8-40

Question 34

gastrulation

Answer 34

division to three primary germ layers: mesoderm, ectoderm, endoderm

Question 35

structures that originate from mesoderm

Answer 35

blood vessels, muscles, connective tissue, bone, urogenital system, cardiovascular system (reason that congenital spine disorders show up with cardiac and kidney and congenital bone defects

Question 36

structures that originate from ectoderm

Answer 36

skin, CNS, cranial and sensory nerves, teeth

Question 37

structures that originate from endoderm

Answer 37

digestive tract, respiratory system

Question 38

neurulation is complete in ___ weeks

Answer 38

4

Question 39

what forms the neural plate?

Answer 39

ectodermal cells thickening

Question 40

how is the neural tube formed?

Answer 40

by the folding of the neural plate

Question 41

how is the neural crest formed?

Answer 41

by the separation of cells from the neural folds

Question 42

the neural tube...(does what?)

Answer 42

forms the CNS, extends from the hindbrain to S2, closes in a cranial to caudal direction by day 28 (end of week 4)

Question 43

the neural crest forms the_____

Answer 43

PNS

Question 44

causes of neural tube defects

Answer 44

genetic, nutritional (folic acid), environment (drugs like valproic acid)

Question 45

types of neural tube defects

Answer 45

anencephaly-failure of neural tube to close cranially, spina bifida: failure of the neural tube to close caudally.

Question 46

endochondral ossification* (add more detail)

Answer 46

long bone development from hyaline cartilage

Question 47

primary ossification center*

Answer 47

diaphysis

Question 48

Osteogenesis*

Answer 48

*

Question 49

secondary ossification center*

Answer 49

growth plate

Question 50

limb development early stage

Answer 50

limb bud development UE before LE

Question 51

apical ectodermal ridge

Answer 51

@ the apex of each limb bud. secretes fibroblast growth factor that induces the limb to grow.