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Flashcards in Exam 1 Review Deck (115):
1

determination

process by which a cell or part of an embyro becomes restricted to a given developmental pathway. (no longer pleuripotent)

2

differentiation

complex of changes involved in progressive specialization of structure and function, often resulting in the formation of luxury molecules

3

growth

permanent increase in mass; hyperplasia = increase in cell number; hypertrophy = increase in cell size

4

morphogenesis

generation of form or assumption of new shape

5

induction

an effect one embryonic tissue (inductor) has on another (responder) such that the development course of the responding tissue is qualitatively changed from what it would have been in the absence of the inductor.

6

integration

process by which different tissues are brought together and combined to form organs and tissues

7

following fertilization, when do primordial germ cells 1st appear?

24 days after fertilization; found in endodermal layer of yolk sac

8

migration route of PGCs into developing gonads from yolk sac

yolk sac --> hindgut epithelium; through dorsal mes; into developing gonads

9

aneuploidy

abnormal number of chromosomes; monosomy/trisomy; could be a result of non disjunction

10

euploidy

changes in the number of complete sets of chromosomes; mono- di- and polyploidy

11

leptotene

2 chromatids; begin to coil

12

what is the genetic make up during prophase I?

2n, 4c

13

when does the synaptonemal complex form?

zygotene

14

pachytene

max coiling; tetrads; cross over begins

15

when are the chiasma well defined?

diplotene

16

diakinesis

cross over complete; terminalization; spindle app in place; nuclear membrane disrupted

17

metaphase I

tetrads line up along equatorial plate; centromeres don't divide

18

when do homologs move to opposite poles?

anaphase I

19

telophase I

cytokenesis; nuclear membrane forms; spindle app disassembles; chromosomes recoil

20

genetic make up during prophase II

1n, 2c

21

prophase II

chromosomes condense; nuc. membranes dissapear; spindle app reforms; haploid

22

when is the second time that chromosomes line up on the equatorial plate?

metaphase II

23

anaphase II

centromeres divide; chromosomes move to opposite poles; chromosomes have 1 chromatid

24

telophase II

chromosomes uncoil; cytokenesis complete; nuc. membrane refroms

25

what is the result of meiosis?

increase in cell numbers (sometimes); non-identical daughter cells (4); daughter cells haploid

26

how does the number of oocytes change from early development to puberty?

7 million at embryonic midterm, 2million remain at birth, 40,000 survive to puberty, 400 will be ovulated

27

what factors lead to meiotic arrest at the diplotene stage?

increased concentration of cAMP inactivates MPF and leads to meiotic arrest

28

what maintains increased concentration of cAMP?

cGMP inactivates phosphodiesterase 3A which prevents cAMP --> 5' AMP

29

role of circulating FSH

stimulates granulosa cells to produce estrogen

30

what causes meiosis to resume the first time?

LH surge by shutting down gap junctions b/w granulosa cells and oocyte

31

aromatase

converts testosterone to b-estradiol

32

B-estradiol / estrogens

stimulate formation of LH receptors on granulosa cells

33

what do LH receptors secrete?

testosterone

34

when does ovulation occur in the ovarian cycle?

day 14 of ovarian cycle

35

what is the stimulus for ovulation?

rise in levels of FSH and sharp rise in LH

36

what components of the graafian follicle form the corpus luteum?

residual theca and granulosa cells proliferate and form a large glandular strucutre called the corpus luteum

37

fate of corpus luteum in absence of fertiliation?

regresses and tissue is replaced by corpus albicans

38

proliferation phase of endometrial cycle

thickness increases by day 14; blood vessels and glands grow; due to an increase in estradiol secreted by granulosa cells

39

secretory phase of endometrial cycle

levels of estrogen decrease and endometrial growth stops; mucous glands begin secretion; spiral arterioles expand; controlled by rising levels of progesterone secreted by granulosa and thecal cells

40

describe graafian follicle immediately prior to ovulation

mature; oocyte arrested in diplotene of prophase I; expansion of follicle by LH FSH; completion of meiosis I; 2nd arrest at metaphase II; formation of stigma

41

fertilization age

age of embryo from time of fertilization

42

menstrual age

age of embryo from start of mother's last mentrual period. 2 weeks greater than fert. age

43

what hormone is necessary for the egg rapid transport through the isthmus?

progesterone

44

what contributions are made to semen by the seminal vesicles?

fructose and prostaglandins

45

what contributions are made to semen by the prostate glands?

citric acid, Zn, Mg, phosphatases

46

what is the optimal pH for sperm motilit?

6 - 6.5

47

what is the pH of the upper vagina?

4.3 -> 7.2 (buffered by seminal fluid)

48

what is the pH of the cervix?

optimal

49

where does fertilization occur?

ampulla

50

what is the purpose of capacitation?

required for sperm to undergo acrosomal rxn

51

where does capacitation occur?

inside uterine tube in isthmus

52

explain how sperm penetrates corona radiata

sperm and acrosome fuse; its membrane fragments release hyaluronidase that breaks down HA in the intracell matrix b/w corona radiata cells; swimming movements help also

53

what is the function of ZP3?

mediates attachment of the sperm to the XP and stimulates the acrosomal rxn

54

fast block to polyspermy

rapid depolarization of plasmalemma; -70 to +10mV w/i 2-3 seconds; prevents poly spermy and allows time for slow block

55

slow block to polyspermy

release of polysaccharides from cortical granules; polysaccharide enters perivitelline space and become hydrated; produces a swelling that increases width of space

56

role of phospholipase C zeta in metabolic activation of egg

introduced by sperm causing release of Ca+ in egg cytoplasm which initiates blocks to polyspermy, stimulates increase in egg respiration and metabolism

57

pronucleus

nuclear material of the head of the spermatozoan or oocyte after oocyte has been penetrated by sperm; normally carries haploid chromosomes

58

zygote

single-celled stage at which male and female pronuclei have fused together and share a common membrane, establishing the diploid chromosome

59

trophoblast

forms extraembryonic strucutres including placenta

60

ICM

forms embryo proper plus some extraembryonic strucutres (yolk sac and amnion); embryonic pole = pole where ICM is located

61

genetic control in invertebrates and non-mammals

early cleavage control is through gene products transcribed form maternal genome

62

genetic control in mammals

maternal gene products are produced but degreaded by 2 cells stage; by 4 cell stage, most transcription is via the embryonic genome

63

Cdx-2 role in differentiation

essential for trophoblast cell differentiation; antagonist toward Oct-4

64

Oct-4 role in differentiation

expressed in developing oocytes and zygote; required to permit cleavage to proceed to 2 cell stage; in all morulas

65

Nanog role in differentiation

produced by inner cells in late morula stage; maintains integretiy of ICM w/ Oct-4

66

what is the differentiation of ICM w/o Nanog

ICM--> endoderm

67

differentiation of ICM w/0 Oct-4

ICM--> trophoblast

68

Sox-2 role in differentiation

1st expressed in 8 cell stage; w/ Oct-4, helps control regulation of genes involved in differentiation

69

genomic imprinting

differential gene expression depending on whether a chromosome is inherited by the male or female parent; refers to the observation that expression of certain genes derived from the egg differs from the expression of the same genes derived from the sperm; due to DNA methylation differences in sperm/egg

70

prader willi

small hands and feet, short stature, poor sexual development, mental retardation, big apetide; mutation is always inherited from father

71

what chromosome is deleted in prader willi and angelman syndrome

long arm of chromosome 15

72

angelman syndrome

frequent laughter, uncontrolled muscle movement, lg. mouth, unusual seizures; mutation is always inherited from mother

73

what are barr bodies?

inactive X chromosome after X inactivation by Xist

74

regulation

ability of embryo to compensate for removal of structures or addition of strucutres; cells aren't fized, can respond to environmental cues

75

dizygotic twins

fraternal; fertilized from 2 different eggs

76

monozygotic twins

identical; 1 fertilzed egg; basis of conjoined twins

77

what's Bateson's Rule?

when duplicated strucutures are joined during critical developmental stage 1 stucuture is the mirror image of the other

78

ZP

surrounds developing embryo until it reaches the uterus and shedding is acomplished through blastocyts hatching

79

what is blastocyst hatching?

small region of ZP dissolved and blastocyste emerges from hole

80

where do ectopic pregnancies most commonly occur?

ampullary (54%)

81

homeodomain

highly conserved region of 60 aa; helix loop helix

82

homeobox

180 nucleotides in the gene that encode the homeodomain

83

Zn finger motif

have Zn bound to polypeptide chain that causes chain to form finger like projections that can be inserted into DNA helix

84

what are 2 Zn finger domains

Sox: high mobility group domain that binds MINOR groove; include SRY
WT1: important for devpt. of embryonic kidney and adult kidney

85

helix - loop - helix

short stretch of aas where 2 alpha helices are separated by an aa loop; involved in homodimerization or heterodimerization

86

maternal effect genes aka egg polarity genes

establish dorsal-ventral and ant-post axes in fly

87

dorsal-ventral egg polarity genes

dorsal, cactus, toll

88

anterior posterior egg polarity genes

bicoid, nanos, hunchback

89

segmentation genes

no genetic maternal effect b/c transcribed after fertiliation; regulated by bicoid and nanos proteins gradients

90

three categories of segmentation genes

Gap genes; pair-rule genes; segment-polarity genes

91

gap genes

delet adjacent segments - hunchback

92

pair rule genes

delete same part of pattern in every other segment

93

segment polarity genes

affect polarity of segment; patched, smoothened, wingless, hh, gooseberry

94

homeotic genes

contian homeobox; determine the identiry of individual segment; products of homeotic genes activate other genes that encode segment-specifc characteristics

95

TGF-B superfamily

consists of a large proregion and bioactive region; ex: BMP - inhibits other processes in embryo

96

FGF family

interaction w/ heparan proteoglycans in receptor complex; regulation at membrane of responding cell via transmembrane proteins; regulated heavily

97

Hedgehog family

related to segment polarity molecule in Dros.; include desert, indian, shh

98

Wnt family

related to seg. polarity genes; interacts w/ components of extracellular matrix; plays different roles in various vert. classes

99

lateral inhibition

dominant cell expressed delta signaling molecules on its cell membrane; delta binds to notch receptors on neighboring cells and represses their genes

100

role of nanog in establishment of epiblast and hypoblast

early expression of Nanog from ICM = determined to become epiblast

101

role of gata 6 in establishment of epibast/hypoblast

cells entering ICM later express Gata-6 and are destined to become hypoblast cells - may be induced by FGF-4 secretion

102

what roles might Wnt and TGF-B play in the formation of the primitive streak?

possibly induce it

103

what are the 3 classical molecular markers expressed by nodal cells?

nodal, goosecoid, foxa-2

104

what are the bottle cells and what's their role in gastrulation

cells that assume a bottle shape due to microtubules and thrust themselved through primitve groove into space and become free = mesenchymal and will reform other layers (mesodermal layers)

105

describe the role of E-cadherin and N cadherin in epithelial - mesenchymal transtion

before induction: ectoderm expresses E cadherin and N-CAM; after nueral tube induction: overlying ectoderm only expresses E cadherin; neural tube ectoderm only expresses N CAM and N cadherins

106

cerebrus-like

originates from ant. visceral endoderm and inhibits development of posterior strucutres

107

DKK-1

originates from ant. visceral endoderm; targets and blocks Wnt; inhibits development of posterior strucutres

108

what 2 signaling molecules are responsible for blocking the development of posterior strucutres in early primitve streak?

Cerebrus like and DKK-1

109

what are the effects of foxa-2 on the early primitive streak?

establishment of prim. node; initiates notochord funtion; establishes midline strucutres cranial to node

110

in late primitive streak stage, what SM is necessary for normal head formation?

cerebrus-like 1

111

in the late primitive streak, what signaling molecules released from primitive streak activate Hox genes?

RA; Wnt; FGF; Nodal;

112

determination

process by which a cell or part of embryo becomes restricted to a given developmental pathway. The point at which a cells becomes committed to a specific cell line

113

differentiation

a complex of change involved in the progressive specialization of strucutre and function; often resulting in the formation of luxury molecules

114

what's the first sign of asymmetry in early development?

beating of cilia around the primitive node

115

roles of nodal and lefty-1 in asymmetyr

TGF-B molecules expressed due to directional current; nodal - symmetry breaking molecules in the left side of embryo; lefty - left side of primitive streak