Gametogenesis (Exam 1) Flashcards Preview

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Flashcards in Gametogenesis (Exam 1) Deck (140)
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1
Q

What are primordial germ cells

A

undifferentiated cells that migrate to the gonadal ridge to become either sperm or egg cells

2
Q

Where do primordial germ cells originate from

A

epiblast

3
Q

Where do primordial germ cells migrate

A

to the yolk sac and then back to the body cavity where they situate themselves in the thoracic region

4
Q

What does the epiblast form

A

the layers of the trilaminar embryo

5
Q

What is the area in the thoracic region where they land

A

genital ridge

6
Q

What does the genital ridge end up forming

A

the ovary or teste

7
Q

Where do primordial germ cells originate from

A

epiblast

8
Q

Where will trilaminar embryo be formed

A

from cells of the epiblast

9
Q

What are primitive sex cords

A

cells surrounding primordial germ cells that originate from genital ridge

10
Q

What is formed in males from sex cord cells

A

sertoli cells

11
Q

What is formed females from sex cord cells

A

follicular cells

12
Q

What are Sertoli cells

A

supporting cells to forming sperm

13
Q

What are Follicular cells

A

surround oocyte

14
Q

When will primordial germ cells come out of dormant state in males

A

puberty

15
Q

What is the role of Leydig cells in male gametogenesis

A

produce testosterone

16
Q

What does testosterone production do

A

stimulate sertoli cells and sperm generating cells to start producing sperm

17
Q

What type of cells are contained within the seminiferous tubules

A

sertoli and sperm-forming cells

18
Q

Where will mature cells be seen in the seminiferous tubules

A

towards the center

19
Q

Where will immature cells be seen in the seminiferous tubules

A

on the outside (they move in as they mature)

20
Q

What is the summary of meiosis in males

A
Spermatogonia
Primary spermatogonia 
2 Secondary spermatogonia
4 Spermatids
Mature Sperm
21
Q

Where does meiosis occur in males

A

in the male reproductive tract

22
Q

How many types of spermatogonia are there

A

two

23
Q

What is spermiogenesis

A

formation of sperm from spermatids

24
Q

What occurs during spermiogenesis

A

formation of acrosome
formation of tail and neck
condenses DNA material
gits rid of cytoplasm and extraorganelles

25
Q

What is the function of the acrosome

A

to help sperm cross zona pellucida and plasma membrane in oocytes

26
Q

Why is the cytoplasm shed in spermiogenesis

A

to make the sperm more streamlined to swim

27
Q

What is capacitation

A

shedding of glycoproteins on the outside of the sperm

28
Q

Where does capacitation occur

A

in the female reproductive tract in response to uterine fluids

29
Q

In females how are oogonia produced

A

female germ cells undergo a series of mitotic divisions after being invested by the sex cords and differentiate into oogonia

30
Q

When does meiosis start for oogonia

A

week 12 of development

31
Q

What occurs during meiosis for oogonia

A

it is halted and becomes dormant until puberty

32
Q

What forms a primordial follicle

A

single, flat layer of cells that form around a primary oocyte

33
Q

How is oocyte division arrested

A

follicle cells produce hormone OMI

34
Q

What does OMI hormone stand for

A

oocyte maturation inhibitor

35
Q

What does OMI do

A

stop the oocyte from finishing division

36
Q

What is the corpus albicans

A

degenerated corpus luteum, a scar tissue in the ovary that is the remnant of the follicle

37
Q

What is the key feature in identifying a graafian follicle

A

antrum

38
Q

What is a key feature of a primary follicle

A

cuboidal follicle cells

39
Q

Where will immature follicles be seen in an ovary

A

less mature are on the outside of the ovary

40
Q

What are the hormones involved in ovulation

A

LH

FSH

41
Q

What is FSH released in response to

A

GnRH

42
Q

What does FSH do

A

stimulate follicles to grow

43
Q

When does FSH production occur

A

during the follicular phase it increases and is highest just prior to ovulation

44
Q

What does FSH causes the production of

A

estrogen

45
Q

When does LH rise

A

during the follicular phase

46
Q

What does LH stimulate the production of

A

progesterone

47
Q

What does progesterone do

A

prepare the uterus for implantation

48
Q

What are the two stages of the ovarian cycle

A

follicular phase

luteal phase

49
Q

How will changes in LH and FSH levels affect follicles in the ovary

A

cause 5-12 primordial follicles to multiply and increase in size and become primary follicles

50
Q

What is the zona pellucida

A

a glycoprotein coat produced by the oocyte and follicular cells

51
Q

What is important about the zona pellucida for fertilization

A

sperm must penetrate this layer via the acrosome

52
Q

What type of follicle will have an antrum

A

Graafian follicle

53
Q

What are the two connective tissue layers found on a graafian follicle

A

theca externa

theca interna

54
Q

What is the function of the theca interna

A

secrete steroids (estrogen and progesterone

55
Q

What is the function of the theca externa

A

connective tissue layer with little function

56
Q

How many primary follicles will develop into graafian follicles

A

1

57
Q

What occurs to the rest of the primary follicles that do not develop into graafian follicles

A

they degenerate

58
Q

When will the oocyte finish meiosis

A

after fertilization

59
Q

What is the oocyte when it is in the ovary

A

a primary oocyte

60
Q

When the oocyte is leaving the ovary, what is it at the time of ovulation

A

a secondary oocyte

61
Q

When does the 2nd meiotic division occur

A

at the time of fertilization

62
Q

How long does meiosis take for females

A

10-50 years

63
Q

How long does meiosis take for males

A

9 weeks

64
Q

When does oogenesis start

A

in utero

65
Q

When does spermatogenesis start

A

just before puberty

66
Q

How many oocytes do women have

A

limited number

67
Q

How many spermatogonia do males have

A

infinite

68
Q

What will happen to the corpus luteum if there is implantation

A

The syncytiotrophoblast secretes hCG to keep the corpus luteum alive to produce progesterone until the placenta starts producing progesterone

69
Q

What will happen to the corpus luteum if no implantation occurs

A

degenerates and the endometrium begins to dissociate

70
Q

What does the syncytiotrophoblast secrete

A

human chorionic gonadotrophic hormone (hCG) that keeps the corpus luteum alive

71
Q

What causes down syndrome

A

Trisomy 21

72
Q

What are the features of down syndrome

A
slanted eyes
growth retardation
varying intellectual disability,
epicanthal folds
flat facies
small ears
cardiac defects
hypotonia
73
Q

What are the features of trisomy 18

A

low-set ears, small mouth, deficient mandible, flexion of the hands, absent and or hypoplasia of the radius and ulna
Intellectual disability
Congenital heart defects

74
Q

What are the features of trisomy 13

A

Intellectual disability
holoprosencephaly
congenital hear defects
deafness, cleft lip and palate, eye defects, microphtlamia, anophthlamia, and coloboma

75
Q

What is Klinefelter syndrome

A

XXY in males

76
Q

What are features

A

gynocomastia, sterility, testicular atrophy, hyalinization of the seminiferous tubules

77
Q

What is the genetic composition of Turner Syndrome

A

X

78
Q

What are the features of Turner’s Syndrome

A
webbed neck
lymphedema
short stature
absence of ovaries
skeletal deformities
broad chest with widely spaced nipples
79
Q

What are the features of Triple X syndrome

A

low self esteem and speech issues

often goes undiagnosed

80
Q

What causes Cri du crat syndrome

A

deletion of short arm of chromosome 5

81
Q

What are the features of Cri du crat syndrome

A

cat-like cry, ID, microcephaly, congenital heart disease

82
Q

What causes Angelman syndrome

A

microdeletion of the long arm of chromosome 15 on the maternal gene

83
Q

What are the features of Angelman syndrome

A

intellectual disability
cannot speak
poor motor development
unprovoked and prolonged periods of laughter

84
Q

What causes Prader-Willi syndrome

A

microdeletion of long arm of chromosome 15 on the paternal gene

85
Q

What are the features of Prader-Willi syndrome

A
obesity
intellectual disability
hypotonia
hypogonadism
undescended testes
86
Q

What causes Fragile X syndrome

A

full mutation occurs where there are more than 200 CGG repeats on the FMR1 gene on X chromosome leading to gene inactivation

87
Q

What are the features of Fragile X syndrome

A

intellectual disability, large ears, prominent jaw, large testes

88
Q

What week of development do germ cells migrate into the yolk sac

A

week 2

89
Q

What week of development do germ cells migrate to the abdominal wall

A

weeks 4-6

90
Q

What are the two types of spermatogonia

A

Type A

Type B

91
Q

What do Type A spermatogonia arise from

A

the stem cell population

92
Q

What do Type A spermatogonia give rise to

A

Type A and Type B spermatogonia

93
Q

How many types of Type A spermatogonia are there

A

two types

94
Q

What are the two types of Type A spermatogonia

A

Dark and Pale

95
Q

What are Dark Type A spermatogonia

A

not dividing, reserve cells

96
Q

What are the Pale Type A spermatogonia

A

giving rise to type A and B spermatogonia

97
Q

What are Type B spermatogonia giving rise to

A

primary spermatocytes via mitosis

98
Q

What occurs during capacitation

A

pruning of the glycocalyx of the sperm to interact with the oocyte

99
Q

Spermatogonia to primary spermatocytes occurs through what

A

mitosis

100
Q

Primary spermatocytes to secondary spermatocytes occurs via what

A

meiosis I

101
Q

Secondary spermatocytes to spermatids occurs via what

A

meiosis

102
Q

spermatids to sperm occurs via what

A

spermiogenesis

103
Q

What is a normal sperm count

A

100 million sperm/ mL

104
Q

What is an infertile sperm count

A

less than 10 million/ mL

105
Q

By month 5, how many oocytes are there

A

7 million

106
Q

At birth, how many oocytes are there

A

600,000-800,000

107
Q

At puberty how many oocytes are there

A

40,000

108
Q

How many oocytes will be ovulated

A

less than 500

109
Q

What secretes GnRH

A

hypothalamus

110
Q

What does GnRH

A

act on the pituitary gland and stimulates the release of FSH and LH

111
Q

What is a vesicular follicle

A

a Graafian follicle (same thing, different name)

112
Q

When is the first meiotic division completed

A

just prior to ovulation to form a secondary oocyte and the first polar body

113
Q

When does the second part of meiosis begin in the oocyte

A

just immediately after ovulation, but halts until fertilization to finish

114
Q

What day of the menstrual cycle does GnRH get produced, LH, FSH start rising

A

5th day

115
Q

What type of follicular cells surround a primordial follicle

A

simple squamous epithelium

116
Q

What are the two stages of primary follicles

A

Unilaminar

Multilaminar

117
Q

What are Unilaminar primary follicles

A
  • simple cuboidal epithelium around

- has a zona pellucida

118
Q

What are multilaminar primary follicles

A

epithelium is stratified

119
Q

What is a vesicular follicle

A

has an antrum that contains liquor folliculi

120
Q

When does ovulation begin and end in a females life

A

puberty and lasts every 30 days for 30-35 years

121
Q

In the menstrual cycle, when does ovulation occur

A

day 14 or 15

122
Q

What is released from the ovary at ovulation

A

secondary oocyte
fluid of Graafian follicle
cells of the cumulus oophorus

123
Q

Secondary oocyte moves into the uterine tube by what

A

fimbria of the uterine tube and by beating cilia lining the oviduct

124
Q

What does the corpus luteum function as

A

an endocrine organ that secretes sterois to maintain the uterine endometrium

125
Q

What are the 3 endocrine events of menstrual cycle

A

GnRH is released by the hypothalamus
GnRH causes the anterior pituitary to release LH and FSH
LH and FSH reach the ovary and causes the release of estradiol and progesterone

126
Q

What are the cyclic changes of FSH

A

rises during the first half of follicular phase
Peaks during ovulation
declines during luteal phase

127
Q

What is the function of FSH

A

stimulate the development of ovarian follicles and production of estrogen

128
Q

What is the cyclic changes of LH

A

rises during first half of follicular phase
peaks just prior to ovulation
declines during luteal phase

129
Q

What is the function of LH

A

serves as the trigger for ovulation

stimulates the production of progesterone

130
Q

What is the cyclic changes of estrogen

A

low in the first half of follicular phase
rises during second half of follicular phase and peaks before LH surge
declines during the beginning of luteal phase but then increases

131
Q

What is the cyclic changes of Progesterone

A

low during follicular phase

begins to increase prior to ovulation

132
Q

In pregnancy, what occurs to progesterone

A

levels remain high

133
Q

If there is no pregnancy, what occurs to progesterone

A

rapidly declines

134
Q

What are the 4 stages of uterine progression

A

menstrual
proliferative phase
secretory
ischemic phase

135
Q

What occurs during the menstrual phase

A

lasts 4-5 days, uterine bleeding due to shedding of the endometrium

136
Q

The first day of bleeding indicates what

A

day one of the ovarian and menstrual cycles

137
Q

What occurs during the proliferative phase

A

period of growth, varies in duration, but typically 10 days

138
Q

When does the proliferative phase end

A

at ovulation

139
Q

What is the secretory phase

A

secretion by uterine endometrium that begins at ovulation

140
Q

What is the ischemic phase

A

constriction of uterine arteries caused by decrease in progesterone