Development of the Urogenital system and Kidney Flashcards
1
Q
Most of the urogenital system develops from the
-located between paraxial and lateral plate mesoderm
A
Intermediate mesoderm
2
Q
The urinary system develops mostly between weeks
A
4 and 7
3
Q
By the end of week 6, the genital system is virtually the same in
A
Both sexes (called indifferent stage)
4
Q
The intermediate mesoderm forms an elevation in the posterior wall of the embryo known as the
A
Urogenital ridge
5
Q
Most of this ridge (the more lateral portion) is the
-will develop into kidney-like structures
A
Nephrogenic ridge
6
Q
At the caudal end of the nephrogenic ridge (in the
lumbosacral region), there is additional intermediate mesoderm known as the
-forms into partof the adult kidney
A
Metanephrogenic blastema
7
Q
A more medial (and shorter) portion of the urogenital ridge is known as the
-will develop into gonad
A
Gonadal ridge
8
Q
Rudimentary filtration structures (renal tubules) in the cervical region that degenerate soon after forming and do not serve an excretory function
A
Pronephros
9
Q
Differentiation of the nephrogenic ridge occurs in a
A
Cranial-caudal direction
10
Q
As more caudal regions differentiate, more cranial regions degenerate. The resulting structure is the
A
Mesonephros
11
Q
Has somewhat more fully developed renal tubules (nephrons) and these do serve an excretory function
A
Mesonephros
12
Q
The mesonephros serves as the kidney for the embryo until the definitive kidney is formed at about
A
10 weeks
13
Q
Caudal end of the hindgut
A
Cloaca
14
Q
Forms in the lateral portion of the nephrogenic ridge, runs the length of the ridge, and enters the anterior portion of the cloaca
A
Mesonephric (Wolffian) duct
15
Q
The urine formed by the mesonephros passes through mesonephric tubules to enter the
A
Mesonephric duct
16
Q
This urine passes down the mesonephric duct, enters the cloaca, and, after rupture of the cloacal membrane (week 7), exits the embryo and enters the
A
Amniotic cavity
17
Q
Envagination from the mesonephric duct that grows towards the metanephrogenic blastema and invades it
A
Ureteric bud
18
Q
The metanephrogenic blastema induces the ureteric bud to begin
A
Branching
19
Q
The ureteric bud induces the metanephrogenic blastema to
A
Differentiate into nephrons
20
Q
The initial branches of the ureter bud form the
A
Renal pelvis and major calyces
21
Q
Later branches of the bud form the
A
Minor calyces and collecting tubules of the kidneys
22
Q
The unbranched portion of the ureteric bud becomes the
A
Ureter
23
Q
The adult kidney forms from two embryonic structures. What forms the
- ) Filtration elements
- ) Conducting elements
A
- ) Metanephrogenic blastema
2. ) Ureter bud
24
Q
Filtration elements, which are mostly in the cortex of the kidneys
A
Nephrons
25
The collecting tubules, calyces, and renal pelvis are the conducting elements of the kidneys and are mostly located in the
Medulla of the kidney
26
The result of failure of the ureteric bud to reach the metanephrogenic blastema
Renal agenesis
27
The kidneys initially develop in the pelvis but then ascends to reach their adult position at the
Upper lumbar levels
28
The initial blood supply to the kidney arises from the
Median sacral artery
29
As the kidneys ascend, the lose their arteries and gain a pair of
Renal arteries (from L2 level of aorta)
30
Sometimes, the kidneys do not lose their initial arteries. These arteries are of high important to a surgeon because they are
End arteries (can not be ligated)
31
During ascention, the kidneys rotate so that the hilus rotates from anterior to
Medial
32
The result of failure of the kidney to ascend
Pelvic kidney
33
If the kidneys fuse during ascention, there will be a single kidney on one side of the abdomen. The most common fusion defect is the
Horseshoe kidney
34
When the lower poles of the kidney fuse and interfere with the ascent of the kidney
-Frequency of 1:500
Horseshoe kidney
35
The fusion seen in horseshoe kidney prevents the kidneys from ascending any highers than the
-hooked over fused portion of kidney
Inferior mesenteric artery (L3)
36
Has a reported frequency of 1:4000 to 1:10,000 and results in oligohydraminos
-incompatible with life
Bilateral renal agenesis
37
Babies with bilateral renal agenesis are born with multiple abnormalities, which is called the
Potter sequence
38
Has a frequency of 1:450 to 1:1000 and usually results in normal excretory function
Unilateral renal genesis
39
If there is interference in the process of fetal swallowing of amniotic fluid and/or its transport to the small intestine for absorption, the resulting excess of amniotic fluid is called
Polyhydraminos
40
GI tract abnormalities and neurological defects that interfere w/ swallowing are associated with
Polyhydraminos
41
The cloaca becomes divided during weeks 4-7 into an anterior portion and a posterior portion, by the
Urorectal septum
42
What do the following become?
1. ) Posterior portion of cloaca
2. ) Anterior portion of cloaca
1. ) Rectoanal canal
| 2. ) Urogenital sinus
43
Formed where the urorectal septum joins the cloacal membrane
Perineal body
44
Forms an extends into the connecting stalk during the 3rd week
- envagination of future cloaca with no function in humans
- included in the umbilical cord
Allantois
45
When the cloaca is divided by the urorectal septum, the allantois remains as an evagination of the
Urogenital sinus
46
Forms from the upper portion of the urogenital sinus and initially remains continuous with the allantois
Urinary bladder
47
The allantois fuses to become a fibrous cord called the urachus, which in the adult is called the
Median umbilical ligament
48
Passes from the dome of the bladder to the umbilicus
Median umbilical ligament
49
If the allantois does not fuse, urine escaped from the bladder and appears at the umbilicus of the infant by way of a
Urachal fistula
50
Can result in a urachal sinus opening into the bladder or at the umbilicus, or a urachal cyst somewhere along the length of the median umbilical ligament
Incomplete fusion of allantois
51
Derived from the urogenital sinus
-incorporates caudal portions of mesonephric ducts and ureter buds as it enlarges
Urinary bladder
52
The portion of the bladder wall which is formed by the incorporated mesonephric ducts becomes the
Trigone of the bladder
53
Initially, the epithelium of the trigone is derived from mesoderm. But eventually, ALL of the epithelium of the baldder is derived from
Endoderm
54
What does the caudal portion of the urogenital sinus become in
1. ) Males
2. ) Females
1. ) Most of urethra
| 2. ) All of urethra and lower portion of vagina
55
What portions of the urethra in males come from the caudal portion of the urogenital sinus?
Prostatic, membranous, and most of the spongy
56
The most distal portion of the urethra in the male, the portion within the glans penis, is derived from the
Glandular plate
57
An ectodermal in growth from the tip of the glans penis
Glandular plate
58
In the male, most of the epithelium of the urethra is derived from endoderm, but the distal portion, the navicular fossa, is derived from
Ectoderm
59
There is a region on the Y chromosome known as the
Sex-Determining Region of the Y chromosome (SRY)
60
The SRY codes for the
-Will cause gonadal ridge to develop into a testis
Testis Determining Factor
61
In the absence of TDF, the gonadal ridge will develop into an
Ovary
62
When the testis develops, testosterone starts being produced by the 8th week from
Leydig cells
63
Produce Müllerian Inhibiting Factor (MIF) which prevents the paramesonephric (Müllerian) ducts from developing into the female genital tract
Sertoli Cells
64
Thus, the development of a normal male genital system is dependent on
TDF, testosterone, and MIF (which are dependent on SRY)
65
What happens in the absence of TDF, testosterone, and MIF
A female develops
66
Can result in overproduction of testosterone in a female resulting in male phenotypic characteristics despite having ovaries and a female genital system
Congenital adrenal hyperplasia
67
Arise from the wall of the yolk sac in the fourth week
| and then migrate along the dorsal mesentery of the hindgut to enter the gonadal ridge in the sixth week
Primordial germ cells
68
Give rise to the cells that enter the meiotic cycle to form gametes
Primordial germ cells
69
This process of gametogenesis begins prior to birth in females and after puberty in
Males
70
The undifferentiated gonad includes a cortex comprised of mesodermally derived epithelial cells and a medulla comprised of
Mesenchyme
71
The cortical epithelium forms finger-like epithelial
cords, called
-grow into the medulla
Primitive sex cords
72
If the gonad becomes a testis under the influence of TDF, the sex cords elaborate in the medulla and become the
-cortex largely regresses
Seminiferous tubules and rete testes
73
In the absence of TDF, the gonad becomes an ovary and the epithelial cells of the cortex develop into
Follicles
74
Which part of the gonad regresses in the development of
1. ) Males
2. ) Females
1. ) Cortex
| 2. ) Medulla
75
The testis develops from the gonadal ridge which is on the medial side of the
Mesonephros
76
In males, some mesonephric tubules are retained and serve as a pathway to carry sperm from the testis to the mesonephric duct. These are called the
Efferent ductules
77
The mesonephric duct, which had been carrying urine when the mesonephros was an excretory organ, now will be used to carry sperm and becomes the
Epididymyus and ductus deferens
78
The caudal portions of the mesonephric ducts form a pair of evaginations called the
Seminal vesicles
79
The portion of the mesonephric duct immediately distal to this evagination becomes the
Ejaculatory duct
80
Develop from endodermal envaginations in the prostatic urethra
Parenchymal cells of the prostate
81
More caudally, the portion of the urogenital sinus
| that becomes the spongy urethra forms a pair of endodermal evaginations which become the
Bulbourethral glands
82
The male and female genital systems are derived mostly from
Mesoderm (some ectoderm (males) and endoderm (both))
83
Gives rise to the testis, efferent ductules, epididymis, ductus deferens, seminal vesicles and ejaculatory ducts
Mesoderm
84
Gives rise to most of the urethra, the prostate and the
| bulbourethral glands
Endoderm
85
Gives rise to the terminal portion of the urethra in males
Ectoderm
86
A second duct formed in females in the lateral portion of the urogenital ridge
- retained in females
- degenerates in males
Paramesonephric (Müllerian) duct
87
The Paramesonephric (Müllerian) duct is retained in females and becomes much of the
Female genital tract
88
Lateral to the mesonephric duct at its craial end
Paramesonephric duct
89
The right and left paramesonephric ducts meet and fuse in the midline. The fused paramesonephric ducts from the
Uterus
90
Defects in the fusion of the paramesonephric ducts may result in duplication of the uterus or formation of a
Bicornuate uterus
91
The medialward movement of the paramesonephric ducts raises folds of the peritoneum to form the
Broad ligament
92
The cranial portions of the paramesonephric ducts which remain unfused become the
Uterine tubes
93
The fused paramesonephric ducts come into contact with the urogenital sinus, causing the endodermal wall of the sinus to thicken and form a pair of
Sinus tubercles
94
These sinus tubules fuse and lengthen, growing in the cranial direction. This lengthened structure is the
Vaginal plate
95
By the 5th month, the vaginal plate canalizes to become the
Lower 2/3 of the vagina
96
Failure of the sinus tubules to fuse may result in a
Double vagina
97
Failure of the vaginal plate to canalize completely results in
Atresia of the vagina
98
The upper portion of the vagina (the region of the cervix and fornix) is derived from the
Caudal end of fused paramesonephric ducts
99
After this canalization, a caudal remnant of the vaginal plate remains as the
-partially separates vaginal canal from vestibule
Hymen
100
Evaginations of the portion of the urogenital sinus that forms
the vestibule form the
Greater vestibular glands
101
Gives rise to the ovary, the uterine tubes, uterus, cervix and the upper part of the vagina
Mesoderm
102
Gives rise to the lower part of the vagina and the vestibule
Endoderm
