1f Genital embryology-SRY gene-Male/female genital homologs- Congenital penile abnormalities-Descent of testes and ovaries Flashcards Preview

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Flashcards in 1f Genital embryology-SRY gene-Male/female genital homologs- Congenital penile abnormalities-Descent of testes and ovaries Deck (34):
1

What is another name for the mesonephric duct, and what four structures are derived from it?

Wolffian duct; Seminal vesicles, Epididymis, Ejaculatory duct, and Ductus deferens (SEED)

2

What is another name for the paramesonephric duct, and what three structures are derived from it?

Müllerian duct; the fallopian tubes, the uterus, and upper portion of the vagina (lower portion is from the urogenital sinus)

3

A child with an XY karyotype has both testes and a uterus. The paramesonephric duct was not suppressed. Which hormone's failure is to blame?

Müllerian inhibitory factor, which is secreted by Sertoli cells, suppresses development of the paramesonephric ducts

4

• What class of hormones promotes the development of the mesonephric ducts in male subjects?

Androgens, which are secreted by Leydig cells

5

Is male or female development the default fetal development?

Female (in the absence of a Y chromosome, female reproductive organs will develop)

6

In female development, the ____ duct degenerates, and the ____ duct develops.

Mesonephric, paramesonephric

7

In male development, the ____ gene on the ____ chromosome codes for testis-determining factor.

SRY; Y

8

In male development, the mesonephric duct develops into all genitourinary internal structures except the ____.

Prostate

9

Which embryologic structure of the genitals degenerates in the female? What does the remnant become?

Mesonephric duct; the Gartner duct

10

Which cells produce Müllerian inhibitory factor in males?

Sertoli cells

11

Which cells produce the androgens that promote development of the mesonephric ducts?

Leydig cells

12

What structure becomes the lower portion of the vagina?

The urogenital sinus

13

A young woman with fully developed secondary sexual characteristics presents with primary amenorrhea. What abnormalities might be present?

Anatomic defects from Müllerian duct abnormalities (fully developed secondary sexual characteristics indicate functional ovaries)

14

A male has no Sertoli cells. What internal and external genitalia will be seen phenotypically?

Both male and female internal genitalia with male external genitalia—Sertoli cells secrete Müllerian inhibitory factor

15

A male subject has 5α-reductase deficiency. What internal and external genitalia will be seen phenotypically?

Male internal genitalia and ambiguous external genitalia until puberty—masculinization from increased testosterone levels during puberty

16

A male newborn has improper degeneration of the paramesonephric (Müllerian) duct. What hormone might be absent?

Müllerian inhibitory factor, which is produced by Sertoli cells

17

What is the function of 5α-reductase?

Converts testosterone to dihydrotestosterone

18

What is the function of dihydrotestosterone?

Promotes development of the genital tubercle and urogenital sinus into male external genitalia and prostate

19

Which chromosome is the SRY gene on?

The Y chromosome

20

A male newborn has improper development of male internal genitalia (except prostate) from the wolffian duct. What hormone might be absent?

Testosterone, which is produced by Leydig cells

21

A male newborn has improper degeneration of the paramesonephric (Müllerian) duct. What hormone might be absent?

Müllerian inhibitory factor, which is produced by Sertoli cells

22

A teenager with the inability to convert testosterone into DHT notes that his ambiguous genitalia are masculinizing. What is happening?

He has 5a-reductase deficiency—increased testosterone levels cause masculinization at the onset of puberty

23

What structures does the genital tubercle form under the influence of dihydrotestosterone (DHT)?

The glans penis, the corpus cavernosum, the corpus spongiosum

24

What two structures does the genital tubercle form under the influence of estrogen?

The glans clitoris and the vestibular bulbs

25

What two structures does the urogenital sinus form under the influence of dihydrotestosterone in the male embryo?

The prostate and the bulbourethral glands (of Cowper)

26

What two structures does the urogenital sinus form under the influence of estrogen in the female embryo?

The greater vestibular glands (of Bartholin) and the urethral and paraurethral glands (of Skene)

27

What structure do the urogenital folds develop into in the male subject, and what structure in the female subject? Hormones responsible?

The ventral shaft of the penis (penile urethra) in the male under dihydrotestosterone—the labia minora in the female under estrogen

28

What structure do labioscrotal swellings develop into in males? What structure in females? What hormones are responsible?

The scrotum in males under dihydrotestosterone; the labia majora in females under estrogen

29

Which is a more common congenital penile abnormality: epispadias or hypospadias?

Hypospadias

30

What are the embryologic etiologies of epispadias and hypospadias?

Epispadias results from faulty positioning of the genital tubercle—hypospadias results from failed fusion of the urethral folds

31

Hypospadias and epispadias refer to the abnormal opening of penile urethra on the ____ and ____ side of the penis, respectively.

Inferior (ventral) ("hypo" is below), superior (dorsal) (when you have Epispadias, you hit yourself in the Eye when you pEE)

32

What two ligaments are formed from the gubernaculum (a band of fibrous tissue) in females? What purpose does the gubernaculum serve in men?

Ovarian ligament and round ligament of the uterus; anchors testes within scrotum in men

33

A man presents with an improperly formed tunica vaginalis. Describe the process of the formation of this structure.

This testes layer is formed from an evagination of the peritoneum (processus vaginalis)

34

A scientist induces apoptosis of a female rat's evagination of peritoneum. Do you worry about any long-term consequences?

No, as this is the processus vaginalis, which is typically obliterated in female subjects