Gametogenesis I

Question 1

define determination

Answer 1

process by which a cell becomes restricted to a given development pathway

Question 2

define differentiation

Answer 2

complex of changes involved in progressive specialization of structure and function

Question 3

hyperplasia

Answer 3

increase in cell number

Question 4

hypertrophy

Answer 4

increase in cell size

Question 5

define morphogenesis

Answer 5

generation of form or assumption of new shape

Question 6

define induction

Answer 6

an effect one embryonic tissue has upon another

such that development course in qualitatively changed from what it would have been w/o the inducer

Question 7

define integration

Answer 7

process in which dif tissues are brought together to form organs and tissues

Question 8

define gametogenesis

Answer 8

generation and development of gametes – sperm cells and oocytes

Question 9

phases of gametogenesis

Answer 9

1. migration to gonads
2. increase in germ cell # via mitosis
3. reduction in chromosomal # via meiosis
4. maturation of eggs and spermatozoa

Question 10

following fertilization, when do the primordial germ cells first appear?

Answer 10

24 days after fertilization

found in endodermal layer of yolk sac

Question 11

trace the migration route of primordial germ cells into the developing gonads from the yolk sac

Answer 11

yolk sac
hindgut epithelium
thru dorsal mesentery
into developing gonads

Question 12

define teratoma

Answer 12

growths from misdirected migrating primordial germ cells

contain mixture of dif tissues

mass of cells w/o axis

Question 13

list the stages of prophase I

Answer 13

leptotene
zygotene
pachytene
diplotene
diakinesis

Question 14

leptotene

Answer 14

chromosomes are threadlike

• consist of 2 chromatids
• begin to coil

Question 15

zygotene

Answer 15

homologous chromosomes pair = synapsis

forming synaptonemal complex

Question 16

pachytene

Answer 16

max coiling achieved
tetrads

crossing over begins

Question 17

diplotene

Answer 17

cross-over continues and chiasmata are well defined

Question 18

diakinesis

Answer 18

crossing over is completed
terminalization

spindle apparatus is in place

nuclear memb disrupted

Question 19

metaphase I

Answer 19

tetrads line up along equatorial plate

centromeres do not divide

Question 20

anaphase I

Answer 20

homologous chromosomes move to opposite poles

not identical due to crossing over

daughters will be haploid

Question 21

telophase I

Answer 21

cytokinesis occurs

nuclear memb. reforms

spindle apparatus disassembles and chromosomes may uncoil

Question 22

prophase II

Answer 22

chromosomes recondense

• -nuclear memb disappears
• -spindle apparatus forms

Question 23

metaphase II

Answer 23

chromosomes line up at equator

Question 24

anaphase II

Answer 24

centromeres divide

chromosomes move to opposite poles
–each consisting of a single chromatid

Question 25

telophase II

Answer 25

chromosomes uncoil
cytokinesis complete
nuclear memb formed

Question 26

end result of meiosis

Answer 26

4 genetically unique haploid daughter cells

Question 27

major events in meiosis

Answer 27

1. pairing of homologous chr = synapsis
2. crossing over
3. 2 rounds of division but only 1 round of DNA replication

Question 28

major results of meiosis

Answer 28

1. increase in cell #
2. daughters are not identical
3. daughters are haploid

Question 29

somatic vs germ cells

Answer 29

nonreproductive body cells

reproductive haploid cells

Question 30

define aneuploidy

Answer 30

abnormal number of chromosomes

monosomy, trisomy

Question 31

changes that can occur in parts of chromosomes

Answer 31

translocations
deletions
inversions
duplications

Question 32

define euploidy

Answer 32

changes in number of complete sets of chromosomes

monoploidy/haploidy = 1 set
diploidy = 2
polyploidy = >2 sets

Question 33

compare total number of oocytes present from embryo to puberty

Answer 33

7 mil - embryonic midterm

2 mil - birth

400k soon after birth

40k puberty

~400-450 actually ovulated thru life

Question 34

destiny for primary oocytes

Answer 34

~400 will be ovulated

out of 40k

the rest will become atretic and die

Question 35

follicular structure — fetal period

Answer 35

oogonia not surround by follicular cells

no follicle

1 chr/cell

Question 36

follicular structure – late fetal period to birth

Answer 36

oocyte arrested at diplotene

primordial follicle formed w/ flat follicle cells

2 chr/cell

Question 37

follicular structure - birth to puberty

Answer 37

diploid oocyte

primary follicle w/ 1 layer cube follicular cells
-zona pellucida separates oocyte from follicular cells

2 chr/cell

Question 38

what connects oocytes and follicle cells

Answer 38

microvilli and gap junctions

Question 39

oocyte during ovulation

Answer 39

proceeds to metaphase II

• -2ndary follicle w/ several layers of cells
• -beginning of antrum formation

2 chr/cell

Question 40

the membrane granulosa surrounds?

Answer 40

outside of follicle cells

Question 41

tertiary follicle formation

Answer 41

forms near end of ovulation
multiple layers of cells
corona radiata
large antrum

Question 42

mural granulosa cells

Answer 42

cells between memb granulosa and antrum

Question 43

cumulus cells

Answer 43

cells between zona pellucida and antrum

Question 44

prior to ovulation the haploid secondary oocyte is with ?

Answer 44

corona radiata
thecal cells
polar body

Question 45

prior to ovulation granulosa cells will develop?

Answer 45

FSH and LH receptors

circulating FSH stims granulosa cells to produce estrogen

Question 46

why is meiosis arrested at metaphase II in oocytes

Answer 46

due to LH surge
which shuts down gap junctions between granulosa cells and oocyte

cAMP reduced
allows activation of MPF

Question 47

ended at tertiary follicle slide 33

Answer 47

slide 33