Chapter 3

Front 1

Amniocentesis

Back 1

Prenatal diagnostic procedure sampling amniotic fluid.

Front 2

Amniotic Cavity

Back 2

Fluid-filled cavity facing epiblast layer.

Front 3

Bilateral Symmetry

Back 3

Each half of the embryo mirrors the other half.

Front 4

Blastocyst

Back 4

Structure formed during prenatal development consisting of trophoblast cells and inner mass of cells that develop into embryo.

Front 5

Cleavage

Back 5

Process during prenatal development when mitosis converts a zygote to a blastocyst.

Front 6

Congenital Malformations

Back 6

Birth defects or developmental problems evident at birth.

Front 7

Cytodifferentiation

Back 7

Development of different cell types.

Front 8

Differentiation

Back 8

Change in embryonic cells to become quite distinct structurally and functionally.

Front 9

Down Syndrome

Back 9

Developmental defect involving trisomy of chromosome no. 21.

Front 10

Ectoderm

Back 10

Layer in trilaminar embryonic disc derived from epiblast layer and lining stomodeum.

Front 11

Ectodermal dysplasia

Back 11

Syndrome involving abnormal development of one or more ectodermal structures including anodontia.

Front 12

Ectopic pregnancy

Back 12

Implantation occurring outside the uterus.

Front 13

Embryo

Back 13

Structure derived from implanted blastocyst.

Front 14

Embryology

Back 14

Study of prenatal development

Front 15

Embryonic cell layers

Back 15

Germ layers derived from increased number of embryonic cells.

Front 16

Embryonic folding

Back 16

Embryonic folding of embryo placing tissue in proper position.

Front 17

Embryonic period

Back 17

Prenatal development time period for embryo from second to eighth week.

Front 18

Bilaminar Embryonic Disc

Back 18

Circular plate of bilayered cells developed from blastocyst.

Front 19

Trilaminar Embryonic Disc

Back 19

Embryonic disc with three layers: ectoderm, mesoderm, endoderm.

Front 20

Caudal End

Back 20

Tail end of structure.

Front 21

Cephalic End

Back 21

Head of structure.

Front 22

Endoderm

Back 22

Layer in trilaminar embryonic disc derived from hypoblast layer.

Front 23

Fertilization

Back 23

Process by which sperm penetrates ovum during preimplantation period.

Front 24

Fetal alcohol syndrome

Back 24

Syndrome in infant during embryonic period resulting from ethanol ingested by pregnant woman.

Front 25

Fetus

Back 25

Structure of fetal period of prenatal development derived from enlarged embryo.

Front 26

Foregut

Back 26

Anterior part of future digestive tract or primitive pharynx that forms oropharynx.

Front 27

Fusion

Back 27

Joining of embryonic tissue of two separate surfaces or elimination of a furrow between two adjacent swellings or developmental disturbance in which adjacent tooth germs unite to form large tooth.

Front 28

Appositional Growth

Back 28

Growth by addition of layers to outside of tissue mass.

Front 29

Interstitial Growth

Back 29

Growth from deep within tissue or organ.

Front 30

Hindgut

Back 30

Posterior part of future digestive tract.

Front 31

Histodifferentiation

Back 31

Development of different tissue types.

Front 32

Implantation

Back 32

Embedding of blastocyst in endometrium.

Front 33

Induction

Back 33

Action of one group of cells on another leading to developmental pathway in responding tissue.

Front 34

Karyotype

Back 34

Photographic analysis of chromosomes.

Front 35

Embryoblast Layer

Back 35

Small inner mass of embryonic cells in blastocyst.

Front 36

Hypoblast Layer

Back 36

Inferior layer in bilaminar disc.

Front 37

Trophoblast Layer

Back 37

Layer of peripheral cells of blastocyst.

Front 38

Maturation

Back 38

Attainment of adult sizes as well as adult form and function.

Front 39

Meiosis

Back 39

Process of reproductive cell production that ensures correct number of chromosomes.

Front 40

Cloacal Membrane

Back 40

Membrane at caudal end of embryo that is the location of the future anus.

Front 41

Oropharyngeal Membrane

Back 41

Membrane at cephalic end of embryo.

Front 42

Mesenchyme

Back 42

Embryonic connective tissue.

Front 43

Mesoderm

Back 43

Embryonic layer located between ectoderm and endoderm.

Front 44

Midgut

Back 44

Middle part of future digestive tract.

Front 45

Morphodifferentiation

Back 45

Development of the differing form that will create a specific structure.

Front 46

Morphogenesis

Back 46

Process of development of specific tissue morphology.

Front 47

Morphology

Back 47

Form of structure.

Front 48

Neutral Crest Cells

Back 48

Specialized group of cells developed from neuroectoderm that migrate from the crest of the neural folds and disperse to specific sites within the mesenchyme.

Front 49

Neutral Folds

Back 49

Raised ridges in the neutral plate that surround deepening neural groove.

Front 50

Neutral Groove

Back 50

Groove from further growth and thickening of neural plate.

Front 51

Neutral Plate

Back 51

Centralized band of cells that extends length of embryo.

Front 52

Neutral Tube

Back 52

Tube formed when neural colds meet and fuse superior to neural groove.

Front 53

Neuroectoderm

Back 53

Specialized group of cells that differentiates from ectoderm.

Front 54

Ovum

Back 54

Female reproductive cell or egg which can be fertilized.

Front 55

Placenta

Back 55

Temporary prenatal organ that provide support to developing embryo.

Front 56

Preimplatation Period

Back 56

Period of unattached conceptus taking place during first week of prenatal development.

Front 57

Prenatal Development

Back 57

Processes that occur from start of pregnancy to birth.

Front 58

Primitive Streak

Back 58

Furrowed, rod-shaped thickening in middle of embryonic disc.

Front 59

Primordium

Back 59

Earliest indication of part or organ during prenatal development.

Front 60

Proliferation

Back 60

Controlled cellular growth.

Front 61

Rubella

Back 61

Viral infection that can serve as teratogen transmitted by way of placenta to embryo.

Front 62

Somites

Back 62

Paired cubodial aggregates of cells differentiated from mesoderm.

Front 63

Sperm

Back 63

Cell containing male contribution of chromosomal information that fertilizes female ovum.

Front 64

Spina bifida

Back 64

Neural tube defect affecting vertebral arches.

Front 65

Syphilis

Back 65

Infective teratogen spirochetes 'Treponema pallidum' that can produce dental anomalies and other defects.

Front 66

Tertogens

Back 66

Environmental agents or factors such as infections, drugs, radiation causing malformations.

Front 67

Tetracycline Stain

Back 67

Intrinsic tooth stain from ingestion of antibiotic tetracycline during tooth development.

Front 68

Treacher Collins Syndrome

Back 68

(or mandibulofacial dysostosis) is due to failure of migration of the neural crest cells to the facial region in the embryo. This results in failure of full facial development, presenting with marked features, including a micrognathia (small lower jaw).

Front 69

Yolk Sac

Back 69

Fluid-filled cavity that faces hypoblast layer.

Front 70

Zygote

Back 70

Fertilized egg from union of ovum and sperm.