Development of urogenital system Flashcards by Aurora H

Intermediate Mesoderm

Following intermediate mesoderm as it becomes ____

ovaries and testes as well and organs that associate with them

How well did you know this?

Not at all

Perfectly

Intermediate Mesoderm

Following intermediate mesoderm as it becomes ovaries and testes as well and organs that associate with them

→ While nephrogenic regions are located within intermediate mesoderm, its surface differentiates into ___

genital ridge

How well did you know this?

Not at all

Perfectly

Migration of Germ Cells

Primordial germ cells , which become the spermatozoa and oocytes, originate in the ___ but migrate to the yolk sac.

epiblast

How well did you know this?

Not at all

Perfectly

Migration of Germ Cells

During the 4th week, they migrate along the ____ to reach the genital ridge in the 6th week.

allantois

How well did you know this?

Not at all

Perfectly

Germ Cells Enter Intermediate Mesoderm

Primordial germ cells take up residence in mesoderm just deep to the genital ridge, region will become ____

medulla of gonads

How well did you know this?

Not at all

Perfectly

Germ Cells Enter Intermediate Mesoderm

Epithelium lining intraembryonic coelom invades mesoderm to form ____

While occurring, nearby ducts approach developing gonads through their developing____

primitive sex cords
mesentery

How well did you know this?

Not at all

Perfectly

Mesonephric and Paramesonephric Ducts

___ drains urine from mesonephric kidney prior to its regression

→ then becomes ducts and organs associated with testis

→ developing under the influence of testosterone

Mesonephric (Wolffian) duct

How well did you know this?

Not at all

Perfectly

Mesonephric and Paramesonephric Ducts

Mesonephric (Wolffian) duct drains urine from___ prior to its regression

→ then becomes ducts and organs associated with testis

→ developing under the influence of testosterone

mesonephric kidney

How well did you know this?

Not at all

Perfectly

Mesonephric and Paramesonephric Ducts

Mesonephric (Wolffian) duct drains urine from___ prior to its regression

→ then becomes ducts and organs associated with testis

→ developing under the influence of ___

testosterone

How well did you know this?

Not at all

Perfectly

Mesonephric and Paramesonephric Ducts

____ involutes into intermediate mesoderm

→ open-ended and becoming ducts and organs associated with ovary

Paramesonephric (Müellarian) duct

How well did you know this?

Not at all

Perfectly

Mesonephric and Paramesonephric Ducts

Paramesonephric (Müellarian) duct involutes into intermediate mesoderm

→ open-ended and becoming ____ (2)

ducts and organs associated with ovary

How well did you know this?

Not at all

Perfectly

Mesonephric and Paramesonephric Ducts

In females, paramesonephric ducts remain open to ____ near the gonad

→ fusing into common body prior to entering posterior aspect of urogenital sinus

intraembryonic coelom (eventual peritoneal cavity)

How well did you know this?

Not at all

Perfectly

Mesonephric and Paramesonephric Ducts

In males, mesonephric ducts closely associate with ____

→ entering urogenital sinus separately on each side

gonads

How well did you know this?

Not at all

Perfectly

Early Development of the Testes

If embryo is genetically male (XY), Y chromosome will transcribe (1)______ and create (2)____

the SRY gene
testis-determining factor (TDF)

How well did you know this?

Not at all

Perfectly

Early Development of the Testes

If embryo is genetically male (XY), Y chromosome will transcribe (1)______ and create (2)____

the SRY gene
testis-determining factor (TDF)

How well did you know this?

Not at all

Perfectly

Early Development of the Testes

TDF induces proliferation of primitive sex cords, which invade developing testis to create ______

→ eventually forming rete testis and seminiferous tubules, which connect to nearby mesonephric ducts

medullary cords

How well did you know this?

Not at all

Perfectly

Early Development of the Testes

TDF induces____, which invade developing testis to create medullary cords

→ eventually forming rete testis and seminiferous tubules, which connect to nearby mesonephric ducts

proliferation of primitive sex cords

How well did you know this?

Not at all

Perfectly

Early Development of the Testes

TDF induces proliferation of primitive sex cords, which invade developing testis to create medullary cords

→ eventually forming ___ and ____, which connect to nearby mesonephric ducts

rete testis and seminiferous tubules

How well did you know this?

Not at all

Perfectly

Early Development of the Testes

Thick epithelium on surface forms _____, which later creates septae that invade testis

tunica albuginea

How well did you know this?

Not at all

Perfectly

Early Development of the Testes

→ identify

How well did you know this?

Not at all

Perfectly

Early Development of the Testes

Factors transcribed downstream of TDF stimulate ____ and ___

formation of Sertoli (from medullary cord) and Leydig (from intermediate mesoderm) cells

How well did you know this?

Not at all

Perfectly

Early Development of the Testes

Factors transcribed downstream of TDF stimulate ____ and ___

formation of Sertoli (from medullary cord) and Leydig (from intermediate mesoderm) cells

How well did you know this?

Not at all

Perfectly

Early Development of the Testes

Factors transcribed downstream of TDF stimulate formation of

Sertoli from ____
Leydig cells from ___

medullary cord
intermediate mesoderm

How well did you know this?

Not at all

Perfectly

Early Development of the Testes

Starting in the 8th week, Leydig cells produce____

testosterone

How well did you know this?

Not at all

Perfectly

**Early Development of the Testes** Starting in the 8th week, Leydig cells produce **testosterone** → Testosterone will induce further development of \_\_\_\_

mesonephric ducts

**Early Development of the Testes** Starting in the 8th week, Leydig cells produce **testosterone** → Testosterone will induce further development of mesonephric ducts → **testis-determining factor (TDF)** also upregulates activity of \_\_

**antiMüllerian hormone (AMH)**

active regression of paramesonephric ducts

**Early Development of the Testes** Factors transcribed downstream of TDF stimulate ____ and \_\_\_

formation of **Sertoli** (from medullary cord) and **Leydig** (from intermediate mesoderm) **cells**

**Mesonephric Ducts** Mesonephric ducts is connected to rete testis → becoming _____ (5)

* **efferent ductules** * **epididymis** * **ductus deferens** * **seminal vesicles** * **ejaculatory ducts**

**Mesonephric Ducts** Small and variable ____ are also remnants of paramesonephric ducts

**testicular appendages** (appendix testis) or **epididymal appendages**

**Mesonephric Ducts** Small and variable **testicular appendages** (appendix testis) or **epididymal appendages** are also \_\_\_\_

remnants of paramesonephric ducts

**Male Reproductive Glands** **\_\_\_\_ and \_\_\_\_** develop from endoderm of urogenital sinus below urinary bladder

**Prostate** and **bulbourethral glands**

**Male Reproductive Glands** **Prostate** and **bulbourethral glands** develop from\_\_\_\_\_ below urinary bladder

endoderm of urogenital sinus

**Male Reproductive Glands** **Prostate** and **bulbourethral glands** develop from endoderm of urogenital sinus below \_\_\_

urinary bladder

**Male Reproductive Glands** Mesonephric ducts gives rise to seminal vesicles, which combine with ductus deferens to create ejaculatory duct → site where ejaculatory ducts empty into urogenital sinus is \_\_\_\_

small remnant of paramesonephric ducts, **prostatic utricle**

**Male Reproductive Glands** Mesonephric ducts gives rise to seminal vesicles, which combine with ductus deferens to create \_\_\_ → site where ejaculatory ducts empty into urogenital sinus is small remnant of paramesonephric ducts, **prostatic utricle**

ejaculatory duct

urogenital sinus

**Early Development of Ovaries** Changes to gonads and ducts dictated by signals received (or not) from gonads themselves If embryo is genetically female (XX), primitive sex cords will regress → epithelium on ovary will proliferate to produce \_\_\_\_

**cortical cords**

**follicular cells**

**Early Development of Ovaries** cluster of follicular cells and oocyte called\_\_\_\_

**primordial follicle**

**Early Development of Ovaries** High levels of ___ stimulate paramesonephric ducts to develop further → mesonephric ducts will regress

**estrogens**

**Early Development of Ovaries** High levels of **estrogens** stimulate ____ to develop further → mesonephric ducts will regress

paramesonephric ducts

**Further Development of Paramesonephric Ducts** Near ovary paramesonephric ducts become \_\_\_\_

**oviducts** (Fallopian tubes)

**Further Development of Paramesonephric Ducts** Near ovary paramesonephric ducts become **oviducts** (Fallopian tubes) → and their fused body will become ___ (3)

**uterus**, **cervix**, and superior part of **vagina**

**Further Development of Paramesonephric Ducts** → identify

**Further Development of Paramesonephric Ducts** Small remnants of mesonephric ducts may be found alongside female reproductive organs → these are ___ (3)

**epoophoron**, **paroophoron**, and **Gartner's** **duct cysts\**

**Development of the Vagina** The urogenital sinus thickens to form ____ where it meets the fused paramesonephric ducts.

**sinovaginal bulbs**

**Development of the Vagina** \_\_\_\_ thickens to form **sinovaginal bulbs** where it meets the fused paramesonephric ducts.

The urogenital sinus

**Development of the Vagina** The urogenital sinus thickens to form ____ where it meets the fused paramesonephric ducts.

**sinovaginal bulbs**

**Development of the Vagina** The urogenital sinus thickens to form **sinovaginal bulbs** where it meets \_\_\_\_

the fused paramesonephric ducts.

**Development of the Vagina** The urogenital sinus thickens to form **sinovaginal bulbs** where it meets the fused paramesonephric ducts. → Together, they form ___ that connects the uterus to the vestibule

a solid structure, the **vaginal plate**

**Development of the Vagina** The urogenital sinus thickens to form **sinovaginal bulbs** where it meets the fused paramesonephric ducts. → Together, they form a solid structure, the **vaginal plate** that connects ____ to \_\_\_

the uterus to the vestibule

**Development of the Vagina** The vaginal plate hollows out to create ___ (3)

the vagina, **vaginal fornix**, and **hymen**.

**Early Development of the External Genitalia** External genitalia develop from\_\_\_\_ as it wraps around body to create pelvis

somatic layer of lateral plate mesoderm

**Early Development of the External Genitalia** External genitalia develop from somatic layer of lateral plate mesoderm as it wraps around body to create pelvis **Cloaca** is covered by ___ and is surrounded by **cloacal fold** on each side

**cloacal membrane**

**Early Development of the External Genitalia** External genitalia develop from somatic layer of lateral plate mesoderm as it wraps around body to create pelvis **Cloaca** is covered by **cloacal membrane** and is surrounded by ____ on each side

**cloacal fold**

**Early Development of the External Genitalia** As _____ separates urogenital sinus from rectum, cloacal folds are re-named **anal** and **urethral folds**; the latter surround **urogenital membrane**

**urorectal septum**

**Early Development of the External Genitalia** As **urorectal septum** separates urogenital sinus from rectum → cloacal folds are re-named ___ and \_\_\_

**anal** and **urethral folds**

**Early Development of the External Genitalia** As **urorectal septum** separates urogenital sinus from rectum → **urethral folds** surround \_\_\_\_

**urogenital membrane**

**Early Development of the External Genitalia** **(1)\_\_\_\_\_** develop laterally to urethral folds and (2)\_\_\_ develops anteriorly

1. **Labioscrotal swellings** 2. **genital tubercle**

**Early Development of the External Genitalia** **Labioscrotal swellings** develop laterally to ___ and **genital tubercle** develops anteriorly

urethral folds

**Development of the Female External Genitalia** Both male and female external genitalia develop from the same starting structures but diverge as they are exposed to different _____ (2)

levels of estrogens or DHT

**Development of the Female External Genitalia** in females, urethral folds remain separate and form\_\_\_\_ on either side of vestibule

**labia minora**

**Development of the Female External Genitalia** in females, urethral folds remain separate and form **labia minora** on either side of \_\_

vestibule

**Development of the Female External Genitalia** in females, urethral folds remain separate and form **labia minora** on either side of vestibule → urogenital membrane ruptures to allow ___ and ___ to reach vestibule

urethral and vaginal openings

**Development of the Female External Genitalia** * Labioscrotal swellings remain separate, making ___ and \_\_\_ * genital tubercle becoming \_\_\_\_

* **labia majora** and part of **mons pubis** * **glans of clitoris**

**Development of the Male External Genitalia** In men, urethral folds zip together on midline and surround urethra → site of fusion is (1)\_\_\_\_\_; this effectively extends urethra toward (2)\_\_\_\_, which is derived from genital tubercle

1. **penile raphe** 2. **glans of penis**

**Development of the Male External Genitalia** In men, urethral folds zip together on midline and surround urethra → site of fusion is **penile raphe** this effectively extends urethra toward **glans of penis**, which is derived from \_\_\_\_

genital tubercle

**Development of the Male External Genitalia** Labioscrotal swellings become (1)\_\_\_ as they enlarge, fuse, and receive descending testes → site of fusion along midline of scrotum is (2)\_\_\_

1. **scrotum** 2. **scrotal raphe**

**Development of the Male External Genitalia** Labioscrotal swellings become **scrotum** as they enlarge, fuse, and receive \_\_\_ → site of fusion along midline of scrotum is **scrotal raphe**

descending testes

**Development of the Male Urethra** \_\_\_, from endoderm-lined urogenital sinus, does not empty to outside until an invagination of ectoderm covering glans of penis meets it and unites two tubes

**Spongy (penile) urethra**

**Development of the Male Urethra** **Spongy (penile) urethra**, from \_\_\_\_, does not empty to outside until an invagination of ectoderm covering glans of penis meets it and unites two tubes

endoderm-lined urogenital sinus

**Development of the Male Urethra** At same time ectoderm around periphery of glans burrows inward creating ____ and separating it from head of penis

**prepuce** (foreskin)

**Development of the Male Urethra** At same time ectoderm around ____ burrows inward creating **prepuce** (foreskin) and separating it from head of penis

periphery of glans

Descent of the gonads

* gubernaculum testis * proper ligament of the ovary + round ligament of the uterus

What are the 2 phases of descent of the testis?

1. transabdominal phase 2. inguinoscrotal phase

What happen during transabdominal phase of Descent of the testis?

- transabdominal phase: from the 7th embryonic week to the 3rd fetal month – the testes descend to the deep inguinal ring (regulated by the AMH) and stay there until the 7th fetal month

What happen during inguinoscrotal phase of descent of testes?

- transabdominal phase: from the 7th embryonic week to the 3rd fetal month – the testes descend to the deep inguinal ring (regulated by the AMH) and stay there until the 7th fetal month

The formation of female external genitalia is regulated by estrogens and the lack of ___ (have in male but not female)

dihydrotestosterone.

External genitalia – sexual dimorphism * genital tubercle will become \_\_\_ * genital folds will become \_\_

* glans penis ; glans clitoridis ♀ * corpus spongiosum and corpora cavernosa penis ♂ ; corpora cavernosa clitoridis and vestibular bulbs ♀

Development of urogenital system Flashcards

(80 cards)