Embryology part 1 Flashcards Preview

USMLE > Embryology part 1 > Flashcards

Flashcards in Embryology part 1 Deck (57):
1

Sonic Hedgehog gene

Organizes embryo along anterior-posterior axis; Produced at base of limbs in zone of polarizing activity. Involved in patterning along anterior-posterior axis

2

Wnt-7 gene

Dorsal-ventral axis; Produced at apical ectodermal ridge (thickened ectoderm at distal end of each developing limb). Necessary for proper organization along dorsal-ventral axis

3

FGF gene

Prodeced at apical ectodermal ridge. Stimulates mitosis of underlying mesoderm, providing for lengthening of limbs; defect= short limbs

4

Homeobox (Hox) gene

Involved in segmental organization of embryo in a craniocaudal direction. Mutations = appendages in wrong location

5

day 2

zygote

6

day 3

morula

7

day 5

blastocyst

8

day 6

blastocyst implantation

9

week 1

hCG secretion after implantation

10

Week 2

bilaminar disc (epiblast, hypoblast); 2 germ layers, 2 cavities (amniotic and yolk), 2 placenta components (cyto/syncytiotrophoblast)

11

Week 3

Trilaminar disc (3 week, 3 germ layers). Gastrulation. Primitive streak, notochord, mesoderm and its organization and neural plate begins to form

12

Week 3 to 8

Embryonic period. Neural tube formed by neuroectoderm and closes by week 4. Organogenesis. Extremely susceptible to teratogens

13

Week 4

4 week, 4 heart chambers, 4 limbs. Heart begins to beat. Upper and lower limb buds begin to form.

14

Week 8 (fetal period)

fetal movement, fetus looks like a baby

15

Week 10

genitalia have male/female characteristics

16

Alar plate

dorsal. Sensory

17

Basal plate

ventral. Motor

18

Notochord derivative

induces overlying ectoderm to become neuroectoderm and form neural plate which gives rise to neural tube and neural crest

19

Surface ectoderm Derivatives

Adenohypophysis from Rathke's pouch (craniopharyngioma-tumor with cholesterol crystals and calcification); lens; epithelial linings of oral cavity, sensory organs of ear, olfactory epithelium; epidermis; anal canal below pectinate line; salivary, sweat, mammary glands

20

Neuroectoderm derivatives

Brain (neurohypophysis, CNS neurons, oligodendrocytes, astrocytes, ependymal cells, pineal gland), retin, spinal cord

21

Neural Crest

ANS, dorsal root ganglia, cranial nerves, celiac ganglion, melanocytes, chromaffin cells of adrenal medulla, parafollicular cells of thyroid, Schwann cells, pia and arachnoid, bones of skull, odontoblasts, aorticopulmonary septum.

22

Endodermal derivatives

Gut tube epithelium (anal canal above pectinate) and derivatives (lungs, liver, pancreas, thymus, parathyroid, thyroid follicular cells)

23

Mesoderm Derivatices

Notochord (nucleus pulposus), Muslce, bone, CT, serous linings, spleen, cardiovascular structures, lymph, blood, bladder, urethra, vagina, eustachian tube, kidneys, adrenal cortex, skin dermis, testes, ovaries.

24

Malformation

intrinsic disruption of developing structure; weeks 3 to 8 are critical

25

Deformation

extrinsic disruption that occurs usually after the embryonic period

26

Agenesis

is an absent organ due to absent primordial tissue

27

Hypoplasia

incomplete organ development and primordial tissue is usually present

28

Aplasia

absent organ despite present primordial tissue

29

ACE Teratogen

Renal damage

30

alkylating agent Teratogen

absence of digits, multiple anomalies

31

aminoglycosides Teratogen

CN VIII toxicity

32

Carbamazepine Teratogen

Neural tube defects, craniofacial defects, fingernail hypoplasia, developmental delay

33

DES

vaginal clear cell adenocarcionoma

34

Folate Antagonists

Neurl tube defects

35

Lithium Teratogen

ebstein's anomaly (atrialized right ventricle)

36

Phenytoin Teratogen

fetal hydantion syndrome: microcephaly, dysmorphic craniofacial features, hypoplastic nails and distal phalanges, cardiac defects, IUGR, mental retardation

37

Tetracycline Teratogen

Discolored teeth

38

Thalidomide

Limb defects

39

Valproate Teratogen

Inhibitition of maternal folate absorption leading to neural tube defects

40

Warfarin Teratogen

Bone deformitites, fetal hemorrhage, abortion, ophthalmologic abnormalities

41

Alcohol Teratogen

Leading cause of birth defects and retardation and microcephaly

42

Cocaine Teratogen

placental abruption; addiction

43

Smoking Teratogen

preterm labor, placental problems, ADHD

44

Iodide Teratogen

Congenital goiter or hypothyroidism

45

Maternal diabetes Teratogen

Caudal regression syndrome (anal atresia to sirenomelia), congenital heart defects, neural tube defects)

46

Vitamin A excess in gestation

Extremely high risk of spontaneous abortions and birth defects (cleft palate, cardiac abnormalities)

47

Developing brain primary vesicles

Week 4: Forebrain (prosenecephalon), Midbrain (mesencephalon), Hindbrain (rhombencephalon)

48

Secondary vesicles of brain (after week4)

Telencephalon and Diencephalon (from prosencephalon); Mesencephalon (from mesencephalon); Metencephalon and myelencephalon (from rhombencephalon)

49

Telencephalon adult structures

Cerebral hemispheres and lateral ventricles

50

Diencephalon

from prosencephalon; thalamus and third ventricle

51

Mesencephalon adult structures

From mesencephalon; Midbrain and aqueduct

52

Metencephalon adult structures

From rhombencephalon; pons and cerebellum and upper fourth ventricle

53

Myelencephalon adult derivatives

From rhombencephalon; Medulla, lower part of fourth ventricle

54

Anencephaly

malformation of anterior end of neural tube; no brain/calvarium, elevated AFP

55

Holoprosencephaly

Associated with Fetal alcohol and Patau's; no separation of hemispheres across midline; cyclopia

56

Chiari II

Herniation through foramen magnum with aqueductal stenosis and hydrocephayly, assoc. with syringomyelia and lumbar myelomeningocele

57

Dandy-walker

Large posterior fossa; absent cerebellar vermis with cystic enlargement of 4th ventricle. Can lead to spina bifida