Reproductive System Development - Articulate Flashcards
1
Q
Major and minor calices develop, Kidneys begin to ascend, Nephrons begin to form, they will connect to collecting tubules and function by 10 weeks
A
Week 6-7
2
Q
Urogentital ridges form from the intermediate mesoderm, and germ cells migrate from the gut wall. Ureteric buds have entered the metanephric mesoderm.
A
Week 5
3
Q
The “indifferent” stage with identical primordia in both sexes
A
2 months
4
Q
In males, primary sex cords from seminiferous tubules. In females, secondary sex cords from ovarian follicles
A
10-12 weeks
5
Q
External genitalia develop
A
3 months
6
Q
Testes pass through the inguinal canal into the scrotum
A
8-9 months
7
Q
What is the urogenital system divided into
A
Urinary system & reproductive (genital system)
8
Q
Where do the Urinary and reproductive system develop from?
A
Intermediate mesoderm
9
Q
Intermediate mesoderm swells to form the
A
Urogenital ridge
10
Q
What does the urogenital ridge differentiate into?
A
Genital ridge & Nephrogenic cord/ridge
11
Q
Formation & differentiation of gonads begins with arrival of
A
Primordial germ cells
12
Q
Where do primoridal germ cells enter to begin gonad formation
A
intermediate mesoderm
13
Q
rimordial germ cells migrate from wall of the yolk sac, along the dorsal mesentery of the hindgut
A
4th week
14
Q
Primordial germ cells arrive at primitive gonads
A
5th week
15
Q
Primoridal germ cells invade genital ridges
A
6th week
16
Q
What happens if the germ cells fail to reach the ridges?
A
Gonads do not develop
17
Q
When is the sex of the embryo genetically determined
A
At the time of fertilization
18
Q
Gonads begin as pair of longitudinal ridges
A
Genital (gonadal) ridges
19
Q
How are the genital ridges formed
A
Proliferation of epithelium & condensation of underlying mesenchyme
20
Q
Epithelial cells of the genital ridge penetrates underlying…
A
Mesenchyme
21
Q
Epithelium of genital ridge proliferates to form a number of irregularly- shaped cords
A
Primitive sex cords
22
Q
Impossible to differentiate between male and femal when the genital ridge proliferates
A
Indifferent gonad
23
Q
During the indifferent gonad stage, both males & females have two pairs of genital ducts called
A
Mesonephric (wolffian) ducts Paramesonephric (Mullerian) ducts
24
Q
Open into urogenital sinus on either side of the sinus tubercle
A
Mesonephric (Wolffian) ducts
25
Runs lateral to mesonephric duct; crosses ventrally
Paramesonephric (Müllerian) ducts
26
In midline, comes in close contact with paramesonephric duct from opposite side
Paramesonephric (Müllerian) ducts
27
Caudal tip of combined ducts projects into posterior wall of urogenital sinus; causes small swelling
Sinus tubercle
28
If embryo is genetically male, primordial germ cells carry an
XY chromosome complex
29
Houses SRY gene
Y chromosome
30
Leads to the developement of testes
Testis-determining factor (TDF)
31
Encodes for testis-determining factor (TDF)
SRY gene
32
Under influence of SRY gene, Primitive sex cords continue to proliferate & penetrate deep into the medulla to form the
Testis (medullary) cords
33
Y chromosome -\> SRY gene -\> TDF -\> Testis
Just a note
34
Primitive sex cords proliferate & penetrate deep into medulla to form
Testis (medullary) cords
35
Towardshilumof testis, testis cords break up into network of tiny cell strands which give rise to
Rete testis
36
Dense layer of fibrous connective tissue; separates testis cords from surface epithelium
Tunica albuginea
37
Testis cords become horseshoe-shaped & continuous with rete testis
4th month
38
What are the testis cords composed of?
Primitive germ cells Sertoli cells (sustentacular cells)
39
Supporting cells
Sertoli cells (sustentacular cells)
40
Where are Sertoli cells (sustentacular cells) derived from?
Testis surface epithelium
41
Where are Leydig cells derived from?
Mesenchyme of gonadal ridge
42
Lie between the testis cords
Leydig cells
43
Another name for leydig cells
Interstitial cells
44
What do leydig cells produce?
Testosterone
45
What week to leydig cells begin to produce testosterone?
Week 8
46
Allows testis able to influence sexual differentiation of genital ducts & external genitalia
Testosterone
47
Remain solid until puberty
Testis cord
48
Testis cords acquire a lumen and become
Seminiferous tubules
49
Seminiferous tubules join rete testis tubules which enter
Ductuli Efferentes (Efferent ductules)
50
Link rete testes & mesonephric (wolffian) duct
Efferent ductules
51
Mesonephric (wolffian) duct gives rise to
Ductus deferens (vas deferens)
52
Stimulates genital ducts to develope
Testosterone
53
What do mesonephric ducts form?
-Efferent ductules -Epididymis -Vas Deferens (ductus deferens) -Seminal Vesicle -Ejaculatory Duct EEE VS
54
Produce Anti-Müllerianhormone (AMH)/Müllerian inhibiting substance (MIS)
Sertoli cells
55
Causes paramesonephric ducts to degenerate
Sertoli cells
56
What don't sertoli cells degenerate?
Appendix testis- small portion at cranial ends
57
Where do testes develop?
Retroperitoneally in abdominal region
58
Move caudally & pass through abdominal wall to reach scrotum
Testes
59
How do testes pass through abdominal wall?
Inguinal canal
60
Condensation of mesenchyme extending from caudal pole of testis; anchors testis to floor of scrotum & assists in its descent into scrotum
Gubernaculum
61
Evagination of peritoneum from abdominal cavity
Processus vaginalis (vaginal process)
62
Follows course of gubernaculum into scrotal swellings
Processus vaginalis (vaginal process)
63
What evaginates into scrotal swelling?
Processus vaginalis + Muscular & fascial layers of body wall
64
Where does evagination into scrotal swelling occur?
Through inguinal canal
65
What coveres testes?
Reflected fold of the processus vaginalis
66
Connects lumen of processus vaginalis with peritoneal cavity
Narrow canal
67
Obliterated shortly after birth
Narrow canal
68
As testis descend through inguinal ring, they get covered by:
-Processus vaginalis -Transversalis fascia -External abdominal oblique muscle
69
- Visceral & Parietal layer of tunica vaginalis
Processus vaginalis
70
Internal spermatic fascia
Transversalis fascia
71
Cremasteric fascia & muscle
Internal abdominal oblique muscle
72
External spermatic fascia
External abdominal oblique
73
Does the transversus abdominus muscle a layer that covers the testes?
NO
74
What chromosomes are femal?
XX
75
-Medullary cords degenerate -Cortical cords develop -No tunica albuginea
Ovary
76
-Medullary cords develop -No cortical cords -Thick tunica albuginea
Testis
77
Dissociate into irregular cell clusters
Primitive (medullary) sex cords
78
Contain groups of primitive germ cells; occupy medullary part of ovary
Primitive (medullary) sex cords
79
In what gender does the surface epithelium of gonad continue to proliferate?
Female
80
Surface epithelium gives rise to a second generation of cords
Cortical cords
81
What week do cortical cords arise
7th
82
Penetrate underlying mesenchyme; remain close to surface
Cortical cords
83
Cortical cors split into isolated cell clusters
3rd month
84
Cells in clusters continue to proliferate; begin to surround each oogonium with a layer of epithelial cells
Follicular cells
85
What makes up primordial follicle?
Oogonium + Follicular cells
86
What happens in presence of estrogen, & absence of testosterone & AMH (MIS)
-Paramesonephric (Müllerian) ducts develop into main female genital ducts -Mesonephric ducts degenerate
87
Develop into main female genital ducts
Paramesonephric (Müllerian) ducts
88
Degenerate in presence of estrogen and absence of testosterone & AMH
Mesonephric ducts
89
3 parts recognized in each duct
-Cranial vertical portion -Hortizonetal part -Caudal vertical part
90
Opens into abdominal cavity
Cranial vertical portion
91
Crosses mesonephric duct
Horizontal part
92
Fuses with counterpart on opposite side
Caudal vertical part
93
What does the paramesonephric duct give rise to?
Uterine tube & Uterine canal
94
Parts of the uterine canal
-Corpus of uterus (corpus uteri) -Cervix -Upper portion of vagina
95
Fused caudal ends of paramesonephricducts contact posterior wall of urogenital sinus; slight thickening forms
Sinus tubercle
96
What do fused tips of paramesonephric ducts fuse with?
Sinus tubercule
97
Two solid evaginations grow out from sinus
Sinovaginal bulbs
98
What do sinovaginal bulbs proliferate and form?
Solid vaginal plate
99
What increases distance between uterus & urogenital sinus
Continuation of cranial end of plate
100
When is vaginal outgrowth entirely canalized?
By the 5th month
101
Wing-like expansions of vagina form around caudal end of uterus?
vaginal fornices
102
What is the origin of vaginal fornices?
Paramesonephric origin
103
Dual origins of vagina
Upper portion & lower portion
104
What is the upper portion of the vagina derived from?
Uterine canal
105
What is the lower portion of the vagina derived from?
Urogenital sinus
106
Lumen of vagina remains separated from urogenital sinus by thin tissue plate
Hymen
107
Where do ovaries begin?
high in abdomen
108
Where do ovaries end up?
They descend and settle just below rim of true pelvis
109
Forms suspensory ligament of the ovary
Cranial genital ligamen
110
Forms ligament of the ovary proper & round ligament of the uterus (extends into the labia majora)
Caudal genital ligament
111
Mesenchymal cells from primitive streak, migrate around cloacal membrane forming
Cloacal folds
112
When are cloacal folds formed?
3rd week
113
Cranial to cloacal membrane, folds unite to form
Genital tubercle
114
Caudally, folds subdivided into
urethral folds (anteriorly) & anal folds(posteriorly)
115
Another pair of elevations becomes visible on each side of the urethral folds
Genital swellings
116
What do genital swellings become?
Scrotal swellings or labia majora
117
Development of external genitalia in males characterized by rapid elongation of genital tubercle
Phallus
118
During elongation, phallus pulls urethral folds forward forming
Lateral walls of urethral grove
119
Groove extends along caudal aspect of elongated phallus; does not reach most distal part
Glans
120
Epithelial lining of the groove
Urethral plate
121
Where does the urethral plate originate?
Endoderm
122
When is the penile urethra formed?
End of the 3rd month
123
The two urethral folds close over urethral plate forming
Penile urethra
124
When is the most distal portion of the urethra formed?
4th month
125
Ectodermal cells from the tip of the glans penetrate inward forming
Short epithelial cord
126
Cord later obtains a lumen and becomes
External urethral meatus
127
Genital swellings in males
Scrotal swellings
128
Arise in the inguinal region and move caudally
Scrotal swellings
129
What separates each half of the scrotum
Scrotal septum
130
Stimulates the development of external genitalia of female
Estrogen
131
What elongates slightly to form the clitoris?
Genital tubercle
132
Do urethral folds fuse?
No, they develop into labia minora
133
Urogenital groove is open, forming
Vestibule of the vagina
