Development Of Urogenital System Flashcards
(67 cards)
1
Q
What part of the trilaminar disc do the urogenital structures and adrenal cortex arise from?
A
Intermediate mesoderm
2
Q
3 stages of kidney development
What direction are these stages going?
A
Pronephros, mesonephros, and metanephros
Cranial to caudal
3
Q
Difference in structure of the mesoderm in the following systems:
- Pronephric system
- Mesonephric system
- Metanephric system
A
- Segmented intermediate mesoderm
- Unsegmented intermediate mesoderm
- Unsegmented mesoderm
4
Q
Solid, unsegmented mass of tissue formed in the lower thoracic, lumbar and sacral regions is called?
A
Nephrogenic cord
5
Q
Pronephros:
- Location
- When does it disappear in mammals?
A
- Cervical region (group of 7-10 solid cell groups)
2. At 4 weeks
6
Q
Mesonephros:
- Mesonephros and mesonephric ducts are derived from intermediate mesoderm from __ to __
- Function? When does it become functional
- Which duct persists in males?
- What happens during regression of the pronephric system?
A
- Upper thoracic to upper lumbar (L3) segments
- Remove wastes - functional during month 2
- Wolffian ducts
- The first excretory tubules of the mesonephros appear
7
Q
Mesonephros- Excretory tubules: 1. They lengthen and acquire \_\_; this will form? 2. Next the tubules form \_\_, where? 3. Laterally, the tubule enters \_\_
A
- Tuft of capillaries that form glomerulus at their medial extremity
- Bowmans capsule around the glomerulus
- Longitudinal collecting duct aka Wolffian duct
8
Q
Mesonephros:
- Next, during the second month, the mesonephros forms __
- Where is this in relation to the developing gonad?
- Ridge formed by both of these organs is called?
A
- Large ovoid organ on each side of midline (will be kidneys)
- Gonad is on medial side of developing kidneys
- Urogenital ridge
9
Q
Mesonephros:
End of second month:
Caudal tubules are still differentiating; what is happening to cranial tubules/glomeruli
A
They have shown degenerative changes, majority disappear by end of 2nd month
10
Q
Mesonephros:
- What happens to the caudal tubules/mesonephric duct in males?
- Females?
A
- They participate in formation of the genital system
2. They disappear
11
Q
METANEPHROS:
- Kidney is now able to perform what function
- Where do its excretory units develop from?
- Excretory unit branches off mesonephric duct as?
A
- Concentrate urine to conserve water
- Metanephric mesoderm (in same manner as mesonephric system)
- Ureteric bud
12
Q
Kidney develops from what 2 sources and what do each provide?
A
Metanephric mesoderm- provides excretory units
Ureteric bud- gives rise to the collecting system
13
Q
Duct system formation:
- Ureteric bud invades__ to induce it to differentiate into the nephron
- Ureteric bud branches repeatedly to form__
- Ureteric bud penetrates __ to form primitive renal pelvis
- Cranial and caudal portions of renal pelvis become?
A
- Metanephric blastema (mesenchyme)
- Collecting portions
- Metanephric tissue
- Major calyxes
14
Q
So ureteric bud gives rise to what 4 things?
A
Ureter, renal pelvis, major/minor calyces and ~1-3 million collecting tubules
15
Q
As embryo grows, metanephric kidney relocates from __ to __ (vertebral levels)
What happens during this relocation
A
From S2 to T12
The blood supply branches from successively more cranial portions of the aorta
16
Q
- Mesenchyme expresses WT1 which regulates production of which two genes? Function?
- What are the receptors for these 2 genes? What kind of receptors are they?
- What do these receptors do?
A
- GDNF and HGF; stimulate branching and growth of the ureteric buds
- RET is receptor for GDNF, MET is receptor for HGF; these are tyrosine kinase receptors
- Establish signals between the epithelium of ureteric buds
17
Q
- Which 2 growth factors stimulate proliferation of mesenchyme/block apoptosis?
- Other function of these 2 growth factors?
A
- FGF2 and BMP7
2. Maintain WT1 expression
18
Q
Function of WT1?
A
Enables tissue to respond to induction by ureteric bud
19
Q
- Ureteric buds convert mesenchyme to an epithelium for __ formation
- This is mediated by expressing what 2 genes?
- These 2 genes up-regulate what 2 genes?
A
- Nephron
- WNT93 and WNT6
- PAXZ and WNT4 (in the metanephric mesenchyme)
20
Q
- PAXZ promotes condensation of mesenchyme to prepare for?
2. WNT4 causes the condensed mensenchyme to __ and form __
A
- Tubule formation
2. Epithelialize and form tubules
21
Q
ECM modifications also occur during kidney development:
- Fibronectin, collagen types I and III are replaced with what 2 things that are characteristic of an epithelial basal lamina
- What two molecules are essential for condensation of the mesenchyme into epithelium?
A
- Laminin and collagen type IV
2. E-cadherins and syndecan
22
Q
Cloaca divides into __ anteriorly and __ posteriorly
Cloaca is divided by what?
A
Urogenital sinus anteriorly and anorectal canal posteriorly
Urorectal septum
23
Q
Urogenital sinus develops what 2 portions? These lead into the
A
Urethral and bladder portion; allantois
24
Q
Allantois regresses to form __; what does this connect?
How is this seen in adults?
A
Urachus; connects apex of the bladder with the umbilicus
Seen in median umbilical fold of adult
25
What happens to the phallic part of the urogenital sinus as the genital tubercle grows?
It gets pulled ventrally
26
1. How does the caudal portions of the mesonephric duct enter the bladder; what does it become
2. How do the ureters enter the bladder
1. They are absorbed into the wall of the urinary bladder during differentiation of the cloaca; becomes the trigone of bladder
2. Ureters are initially outgrowths from the mesonephric ducts, enter the bladder separately
27
What happens to the orifices of the mesonephric ducts as the kidney ascends cranially?
What do they become
Move close together to enter the prostatic urethra, then become the ejaculatory ducts (in males)
28
1. What layer of the trilaminar disc does the bladder/urethra epithelium arise from
2. Surrounding connective tissue and smooth muscle come from ?
1. Endoderm
| 2. Visceral mesoderm
29
Epithelium of prostatic urethra begins to form outgrowths, what do these become in males and females
Males- prostate gland
| Females- cranial part of urethra gives rise to the urethral and paraurethral glands
30
In males, the mesonephric duct becomes
Vas deferens
31
Trigone is derived from what layer? Be specific
Trigone is from intermediate mesoderm but is lined with endodermal epithelium later
32
Renal agenesis:
1. Cause?
2. Symptoms?
1. Lack of ureteric bud
| 2. No symptoms if unilateral; if bilateral = oligohydramnios, compressed fetus, stillbirth
33
What will cause a pelvic kidney?
Failure of kidney to ascend
34
What is a horseshoe kidney?
Caused by ?
Fusion of kidneys
Ascent blocked by IMA
35
Ectopic ureters may empty into what 2 places?
Urethra or vagina
36
Wilms tumor is the most common?
Childhood cancer
37
Polycystic kidney disease:
Is it genetic?
Treatment?
Yes
Dialysis/transplantation
38
Urachal fistula, cyst, or sinus:
1. What is it?
2. What can it cause
1. Persistent lumen of allantois
| 2. May allow urine to drain from umbilicus
39
Intro to formation of gonads:
Where is the paramesonephric (Mullerian) duct formed?
What develops into somatic support cells?
When germ cells migrate into the intermediate mesoderm, what do they form
In the lateral coelomic epithelium
Cells of coelomic epithelium develop into somatic support cells
Genital ridge
40
Formation of gonads:
1. At beginning of week 5, primordial germ cells arrive at the primitive gonads by migrating along __
2. In the 6th week, what do these primordial germ cells do? Why?
1. Dorsal mesentery of the hindgut
| 2. Invade the genital ridge; these germ cells influence development of either ovary or testis
41
1. How do gonads appear initially?
| 2. So, to recap, germs cells do not appear where until the 6th week of development?
1. Pair of longitudinal ridges (genital/gonadal ridges)
| 2. Genital ridges
42
1. Gonads are formed by proliferation of __ and condensation of __
2. What does this form?
3. Does this happen before, during, or after primordial germ cells arrive?
1. Proliferation of epithelium and condensation of underlying mesenchyme
2. Primitive sex cords
3. Before and during
43
Primitive sex cords:
1. Location and function
2. What kind of cells form the primitive sex cords?
3. Somatic support cells form what cells in males and females?
1. Surround germ cells; necessary for their development/nutrition
2. Somatic support cells
3. Males= sertoli cells; females= ovarian follicle cells
44
1. Recap- 2 types of mesonephric ducts
2. Where do mesonephric ducts enter the bladder?
3. What do the paramesonephric ducts have to do before they enter the pelvic urethra, why?
1. Mesonephric (wolffian) and paramesonephric (mullerian)
2. At the base of the trigone
3. Fuse in the midline because they are open at their cranial ends
45
1. What is the SRY gene?
2. What 2 things happen if testis-determining factor is present?
3. Sertoli cells then do what
4. Why is testosterone necessary at this stage?
1. A gene on the Y chromosome that produces testis-determining factor
2. Somatic support cells differentiate into sertoli cells and secrete AMH (anti-mullerian hormone)
3. Sertoli cells recruit cells to form Leydig cells that secrete testosterone
4. Without testosterone, the mesonephric duct would degenerate
46
Under influence of SRY gene, primitive sex cords continue to proliferate and penetrate deep into __ to form?
Deep into medulla to form testis or medullary cords
47
Tunica albuginea is developed to separate?
Testis cords from the surface epithelium
48
1. Testis cords become horseshoe shaped and continuous with __
2. Ductuli efferentes differentiate from? where do they enter?
1. Rete testis
| 2. Excretory mesonephric tubules; enter mesonephric duct
49
Development of testes:
1. At this point, testis cords are composed of what 2 types of cells?
2. What type of cells lie between the testis cords? When do they begin development?
1. Primitive germ cells and sustentacular cells of sertoli
| 2. Interstitial cells of leydig; after onset of differentiation of these cords
50
Development of testes:
1. Sexual differentiation begins by the 8th week and is initiated by?
2. Testis cords remain solid until puberty; when they do acquire a lumen, what do they form?
1. Leydig cells beginning production of testosterone
| 2. When they acquire a lumen, it forms the seminiferous tubules
51
When seminiferous tubules are canalized, they join __ tubules which enter __
Seminiferous tubules -> rete testis tubules -> ductuli efferentes
52
Development of ovary:
1. Since females have no Y chromosome, what happens to the primitive sex cords?
2. These cells eventually become?
3. Fate of surface epithelium of female gonad vs male
4. What happens during 7th week
1. Primitive sex cords dissociate into irregular cell clusters
2. Ovarian medulla
3. Female epithelium proliferates; males does not
4. Second generation of cords (cortical cords) arise
53
1. What happens to the cortical cords in the 3rd month
2. Fate of these cells?
3. Oogonia + follicular cells = ?
1. Cords split into isolated cell clusters
2. Continue proliferation and surround oogonium formed follicular cells
3. Primordial follicle
54
1. Mesonephric duct becomes?
| 2. Paramesonephric duct becomes?
1. Vas deferens and epididymis
| 2. Corpus/cervix of uterus and upper portion of vagina
55
Gubernaculum connects
Male/female gonads to the inguinal region
56
Location/what they develop into of the following parts of the developing paramesonephric ducts:
1. Cranial vertical portion
2. Horizontal portion
3. Caudal vertical portion
1. Opens into abdominal cavity-develops into uterine tube
2. Crosses mesonephric duct- develops into uterine tube
3. Fuses with its partner from opposite side- forms the uterine canal
57
1. What separates the uterus from urogenital sinus?
| 2. What 2 things divide the pelvic cavity into uterorectal and uterovesical pouch
1. Sinus tubercle
| 2. Uterus and broad ligaments
58
1. Upper 1/3 of vagina is derived from __ via __
2. Lower 2/3 of vagina is derived from __ via __
3. Hymen separates?
1. Intermediate mesoderm via the paramesonephric ducts
2. Endoderm via the urogenital sinus
3. Vagina and urogenital sinus
59
SOX9
1. Gene that works with SRY (master gene) to induce?
2. Helps regulate what genes expression?
3. SRY/SOX9 induces testes to secrete FGF9 which does what?
4. Thru SOX9, SRY upregulates production of SF1 which does what 3 things?
1. Testes differentiation
2. AMH
3. Causes tubules from mesonephric duct to penetrate gonadal ridge
4. Elevates AMH, stimulates differentiation of sertoli and leydig cells, and upregulates genes for enzymes that synthesize testosterone in leydig cells
60
1. WNT4 function?
2. Function of estrogen in sexual differentiation
3. Main gene that WNT4 upregulates and its function
1. Ovary determining gene; regulates expression of genes responsible for ovarian differentiation
2. Stimulates mullerian ducts to forms external and internal genitalia of female
3. DAXI - inhibits the function of SOX9
61
Male external genitalia:
1. What is the phallus
2. What forms the shaft of the penis
3. Distal tip of urethra is derived from
4. What forms the scrotum
1. Rapid elongation of the genital tubercle
2. Phallus pulling the urethral folds together as it grows fuse and form shaft
3. Ectoderm
4. Genital swellings -> scrotal swellings which fuse to form scrotum
62
Female external genitalia:
1. What forms the clitoris?
2. What forms the labia minora?
3. What forms the labia majora?
4. What forms the vestibule?
1. Genital tubercle
2. Urethral folds
3. Genital swellings enlarging
4. Urogenital groove (is open)
63
Hypospadias (male abnormality):
1. Occurs when?
2. May be associated with what 2 things?
3. How can it look?
1. Urethral folds fail to fuse along the ventral surface
2. Decreased sperm counts and increased risk of testicular cancer
3. If large enough, can look like labial folds
64
Cryptorchidism:
1. Aka
2. Caused by
3. Causes?
1. Hidden testis
2. Testis gets stuck along the way when migrating thru inguinal canal
3. Cannot produce sperm; high incidence of cancer
65
1. Hydrocele is formed by? What will it cause?
| 2. Congenital inguinal hernia is formed by?
1. If vaginal process (pouch of peritoneum) fails to close entirely, fluid filled cysts form
2. If vaginal process fails to close at all
66
Congenital adrenal hyperplasia:
1. How does it present
2. What is it caused by
1. Exaggerated external genitalia (fused labia majora and enlarged clitoris)
2. Increase androgen production, high levels of ACTH, decreased aldosterone and cortisol production
67
Androgen insensitivity syndrome
1. Aka
2. How does it present
3. Caused by?
4. Location of testes?
1. Testicular feminization syndrome
2. Testes are present, but appear to be female
3. Decreased androgens produced by testes, AMH is still produced though, short vagina is present even though they are genetically male
4. Can be abdominal; must be removed because high risk of testicular cancer
