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Flashcards in Genital Development Deck (147):
1

Origin of .... Nervous system

ectoderm

2

Origin of ....muscle

mesoderm

3

Origin of ....digestive system

endoderm

4

Origin of ....urinary and skeletal

mesoderm

5

Origin of ....reproductive tract (vagina, vestibule, penis, clitoris)

ectoderm

6

Origin of ....skin, hair, nails, sweat glands

ectoderm

7

Origin of ....reproductive system (gonads, uterus, cervix, par of vagina, epididymus, ductus deferens, accessory sex glands)

mesoderm

8

First step after fertilization (2)

migration of primordial germ cells from yolk sac (first 15% of gestation)

9

second step after fertilization (2)

sex cords develop in gonad,
paramesonephric ducts develop

10

third step after fertilization (2)

sex is evident from structures (not just histologically anymore)

11

Sex determination (2)

initially at fertilization
subsequent genetic control of differentiation

12

What forms the germ line?

mesoderm and endoderm from epiblast cells (good for stem cell stuff)

13

What is the big journey?

primordial germ cells go from embryonic disk to yolk sac and part of the allantois
Chemotaxis is involved
Birds use passive methods through blood

14

What makes the ridges again?

intermediate mesoderm

15

Teratomata

bugs? that form teeth (tumors) on body walls or anything

16

on the ridge from thoracic to lumbar, ____ is medial and _____ is lateral

gonadal, urinary (main ridge)

17

Gonadal ridge cells come from... (3)

local mesenchyme
coelomic epithelium
mesonephric tubule cells

18

PGCs stimulate...

cells around to proliferate causing ridge elongation

19

Degenerating mesonephric tubules turn into...

compact strands of primitive sex cords which incorporate PGCs

20

WT-1 (2)

forms gonads
Wilmes Tumor -1

21

Lim-1

also required for gonad formation (absence leads to no gonads)

22

Steriodogenesis Factor -1

induces differentiation of Sertoli and Leydig cells

23

Sexually indifferent stage

Embryo is not committed to particular sex development.

24

Paramesonephric ducts = (2)

Mullerian ducts
develop when mesonephros is developing

25

Two things in the first 10-15% of gest (2)

development of metanephros
migration of PGCs to gonadal ridge

Compare these two

26

Mesonephric duct becomes...

epididymus

27

SRY

on Y chromosome that determines

28

SRY gene (3)

On the Y chromosome (on sex determining region
Encodes SRY protein which is made by primitive sex cords in the primitive gonad
Stimulates male reproductive system

29

Genetic Sex Differentiation (2)

Differentiation where the SRY genes are enconded, the male reproductive system is stimulated

30

What do AMH and testosterone…

Degenerate the paramesonephric duct

31

Desert Hedge-hog (2)

At about 27%
Differentiates fetal Leydig cells which produce testosterone and DHT

32

Testosterone develops

Male duct system (around 33%)

33

DHT develops

Penis, scrotum, and accessory sex glands (around 33%)

34

SRY protein leads to…

Testes developing

35

Once the testes develop, …

Sertoli cells secrete AMH (Anti-Mullerian Hormone) and DHT

36

Presence of sertoli cells and what it secretes, ….

Expresses DHH gene and causes AMH and testosterone to do their work

37

Developmental sequence of Testes (5)

Sex cords align with rete tubules
5-15 mesonephic tubules will penetrate toward the rete tubules
rete and mesonephric tubules interconnect (continuity now)
Sex cords become epithelial (epithelial cords)
paramesonephric duct degenerates (why?)

38

Tunica albuginea

outer layer of CT with coelomic epithelia

39

Mesonephric tubules become...

future efferent ducts

40

epithelial cords (sex cords) become...

seminiferous tubules

41

Two other names for mesenchyme in testes and function (3)

Interstitial cells
Leydig cells

primary testosterone

42

Function of sertoli cells (3)

Blood-testes barrier
Increase testosterone around cells
Differentiates cells (with help from Androgen Binding protein)

43

Function of androgen binding protein (2)

Binds to testosterone, DHT, and one more
Makes these more lipophilic and artificially lowers concentrations so more testosterone and such moves in (acts as a sink)

44

Seminiferous cords come from

primitive sex cords and become solid tubules containing germ cells

45

Sertoli cells come from...

mesonephric derived cells

46

Development of seminiferous tubules, ..

15-20 mesonephric derived cells surround about 4 pre-spermatogonia

47

Function of Interstitial (mesenchymal, leydig) cells (3)

form CT septa to divide testes into lobules

Less developed in ruminants
Horses septa have smooth muscle

48

Semifierous cords become...

seminiferous tubules with a lumen

49

from the mesonephric duct inward... (6)

Mesonephric duct (also ductus deferens)---> the epididymis part of the mesonephric duct ---> efferent ducts ---> rete testes ---> seminiferous tubules. All surrounded by Tunica Albuginea

50

mesonephric duct becomes ... (2)

ductus deferens and epididymis

51

Excurrent Extragonal Duct System

efferent ducts, epididymis, and ductus deferens which carry sperm to urethra

52

Tubule canalization in horses...

2 years

53

Tubule canalization in humans

12-14 years

54

Tubule canalization in dogs

9-10 months

55

Tubule canalization in sheep

5 months

56

Tubule canalization in cows

6-8 months

57

Which accessory sex glands does a dog have

only the prostrate

58

accessory sex glands of a bull

bulbourethral glands, seminal vesicles, and ampullae ductus deferentis, prostate

59

accessory sex glands of a ram

bulbourethral glands, seminal vesicles, and ampullae ductus deferentis, prostate

60

accessory sex glands of a boar

bulbourethral glands, seminal vesicles, and ampullae ductus deferentis, prostate

61

accessory sex glands of stallion

bulbourethral glands, seminal vesicles, and ampullae ductus deferentis, prostate

62

accessory sex glands of lab animals

bulbourethral glands, seminal vesicles, and ampullae ductus deferentis, prostate

63

accessory sex glands of a cat

bulbourethral glands, (NOT seminal vesicles), and ampullae ductus deferentis, and prostate

64

Where do seminal vesicles and ductus deferens come from...

epithelial EVaginations from mesonephric duct

65

Prostrate and bulbourethral glands come from...

epithelial Evaginations from urogenital sinus

66

Accessory glands depend on..

androgens

67

Accessory glands happen at about what time..(2)

30% of gestation
same a duct system differentiation

68

gubernaculum (2)

ligamentous structure that grows and regresses quickly to allow the testes to move from retroperitoneal position to scrotum

69

No descent in....(4)

armadillos
elephants
aquatics
Birds

70

Layers of peritoneum the testes have to go through (2)

visceral vaginal tunic
parietal vaginal tunic

71

Stages of testes descent (2)

transabdominal phase
inguinal-scrotal phase

72

Transabdominal phase (3)

testes (retroperit) attached to gubernaculum caudally
Gubernaculum and peritoneal cells join
gubernaculum grows towards and into the scrotal region

73

inguinal-scrotal phase (2 - big guys)

Gubernaculum penetrates inguinal ring and testes move into intestinal canal because of rapid gubernaculum growth (depends on androgens)

gubernaculum shrinks moving testes into inguinal opening and further until peritoneum surrounds

74

Vaginal cavity

potential space between the visceral and parietal tunics in the scrotum

75

Testes for ruminants descend

mid-gestation

76

testes for boars and humans descend

last quarter

77

horses testes descend..

just before or after birth

78

Inguinal hernias

common in swine
ligate visceral and parietal tunics

79

When there is no SRY... (5)

Female genes inhibit male genes
Ovaries develop
No AMH
The whole system develops
20-33% times in gestation

80

Dax-1

suppresses formation of testes

81

WNT 4 (2)

essential for formation of female repro tract
(also, important to make full nephron)

82

Streak gonads

a result of PGCs not making it to the ridge (medial ridge remember)

83

paramesonephric ducts become (2, 5 parts)

Infundibulum, oviducts, uterus, cervix, and part of vagina
at 27% of gestation

84

tip of the paramesonephric duct becomes

infundibulum (enlarges to become this)

85

Ovary Developmental sequence (4)

cells from sex cords break away(maybe), surround PGCs, and differentiate into primitive follicular cells

Mesonephric duct regresses at the same time as the rete tubules.

Primitive follicular cells surround PGCs stay in cortex

Sex cords disappear and in it's place, the cortex and non-germinal medulla

86

PGCs in the ovary are called

oogonia

87

coelomic epithelium of the ridge become...

cortex of ovary

88

Follicles arrangement (3)

usually in the cortex of the ovary
Dogs and cats are clustered
Ruminants and swine are randomly distributed

89

Equine Ovary differences (3)

Follicles are in medulla
ovaries are in close contact with epithelium and ovulation happens right there
They have the ovarian fossa

90

Ovulation fossa is...

where more central oocytes can be released from
ovary becomes concave, keeping the coelom

91

Meso-salpinx

part of the broad ligament that goes from the ovary to the uterine tube

92

Oviduct is synonymous with

salpinx

93

Final position of ovaries after descending posteriorly... (2)

suspensory ligament of ovary
proper ligament of the ovary

94

Suspensory ligament used to..

suspend the mesonephros

95

proper ligament is a portion of the...

gubernaculum

96

Development of paramesonephric ducts (3)

open to abdomen cranially
interacts with the urogenital sinus caudally
the two fuse together near the attachment at the urogenital sinus

97

Caudal urogenital sinus becomes.. (female)

vestibule

98

Cranial urogenital sinus becomes... (female)

bladder

99

Fused paramesonephric ducts become .... (female)

cervix and uterine body

100

Mares and cows have _____ uteri

bicornuate

101

marsupials and rabbits have ______ uteri

duplex

102

bitch, queen, and sow have _______ uteri

bicornuate but really developed

103

Primate have _____ uteri

simplex

104

Gland development in the uterus makes...

histotrophe

105

gland development in pigs and sheep is

fast and right after birth

106

gland development in horses is

slow (all the way to puberty)

107

Steps in the development of female reproductive tract ducts (3 steps - not good for a notecard but whatever)

A small bud evaginates from urogenital sinus and fuses with paramesonephric duct (caudal part to caudal part)

A more defined cervix forms by fusing with the paramesonephric duct

The urogenital sinus then elongates

108

Vestibule originates from..

urogenital sinus (invagination of skin)

109

Once urogenital sinus and paramesonephric ducts fuse, ...

we have a continuous duct system (YAY?)

110

Cranial vagina, cervix and uterus come from...

paramesonephric ducts (mesoderm)

111

Epithelial buds in urethra and urogenital sinus make...

urethral and vestibular glands

112

urethral gland in the female =

the prostate in males

113

the bulbourethral gland in males =

vestibular gland in females

114

Support of the female tract is ...

broad ligament (surrounds uterus - supports dorsally and laterally)

115

In cranial parts, the female gonad and paramesonephric duct are _____

Seperate, they fuse as you go caudally (and rotate a little bit)

116

In caudal parts, the paramesonephric ducts will ____ and make the _____, _____, and cranial part of ______

fuse
body of uterus
cervix
cranial part of the vagina

117

Male and female gonads and duct systems originate....

behind the peritoneum (retroperitoneal)

118

More caudally from the cranial parts in the female, ...

gonadal ridges and paramesonephric ducts move ventrally but do not fuse. There is some rotation starting here (medially)

119

In the fusion process, the female reproductive tract is sandwiched between....

two layers of peritoneum called the GENITAL FOLD

120

The genital fold becomes

the broad ligament

121

Before sex is differentiated in the embryo, mesenchymal cells from the primitive streak will...(2)

move around the cloacal membrane
and form the two cloacal folds

122

What happens to the cloacal folds? (2)

fuse to make the genital tubercle
also, they subdivide into anal and urogenital folds (with anal and urogenital membranes)

123

Mesoderm lateral to each urogenital fold will then... (2)

proliferate and elavate making the LABIO-SCROTAL or GENITAL SWELLINGS

124

What chemical is a potent inducer of female genitalia?

17 beta estradiol (estrogens)

125

What family of chemicals drives male external genitalia?

androgens, dihydroxytestosterone

126

Genital tubercle gives rise to...

clitoris

127

Urogenital folds (don't fuse and) give rise to...

labia

128

steroid influence of external genitalia in males does...

genital tubercle elongates into the phallus

129

line of fusion in male genitalia =

scrotal raphe

130

Urethral groove is.. (male genitalia)

an epithelial cord forming inside the fusing urogenital folds. (The urogenital folds make the lateral boundaries of the urethral plate and the urethral groove is inside that)

131

Penile urethra results after

the urogenital folds enclose the urethral groove

132

The urethral plate does not go to the tip, but instead...

an ectodermal invagination wil fuse with the endodermal cells lining the penile urethra.

133

Before the penile urethra opens at the tip, ...

canalisation needs to happen

134

Oss penis is

when the glans penis grows and ossifies

135

Mammary ridges are...

ventral epidermal thickenings that go from axillary region to inguinal region of embryo

136

Steps in development of mammaries (4)

1. primary buds develop (epidermal tissue moves inward and penetrates mesenchyme (dermis)
2. primary buds branches further into dermis to make Secondary Mammary buds
3. Secondaries continue to increase in length and branch
4. Canalisation so each gland has a lactiferous sinus

137

Proper alveolar and duct system is constructed and finally finished ...

between puberty and pregnancy and finally during the first trimester of pregnancy

138

4 levels of opportunity for defects in genital systems

1. chromosomal level
2. gonadal differentiation
3. duct system differentiation
4. development of external genitalia

139

Turner's syndrome (3)

Gonadal degenesis
Only one X (one x must be present for viability)
PGCs reach gonad but soon degenerate

140

Turner's syndrome symptoms (4)

hypoplastic ovary
small uterus
underdeveloped external genitalia
infantile genitalia from lack of gonadal hormones

141

Turner's syndrome is common in

horses (not as much in humans, pigs, dogs, and cats

142

Klinefelter's syndrome (2)

XXY karyotype
Found in humans, dogs, and cats

143

Symptoms of Klinefelter's (2)

embryo develops male gonads, produces male related hormones, seems like a male

XX chromosomes drives female genes causing hypoplastic testes and infertility (no spermatogenesis)

144

Hermaphroditism (2)

Defect is early on
ovarian and testicular tissues present (separate or together (OVOTESTES)

145

Pseudo-hermaphroditism (2)

common form of intersex
sex is determines by gonads (mostly male)

146

Hypospadias (3)

urethra opens on ventral surface of penis
results from urethral groove not closing in the male
Common in some dog breeds

147

Two other types of genital deformalities... (2)

wrong fusion of uterus giving different types
hypoplasia of testes