Yan: Genital System Flashcards by Megan Foggia

When is sex determined? When does male/female morphology develop?

at fertilization; 7th week

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What are genital (gonadal) ridges derived from?

Proliferation of epithelium and condensation of underlying mesenchyme

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When do germ cells appear?

At the 6th week

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Primordial germ cells are endodermal cells in the wall of the (blank) close to the allatois. They migrate by ameboid movement along the (blank) of the hindgut. When do they arrive at the primitive gonads? When do they invade gonadal ridges?

yolk sac; dorsal mesentery; 5th week; 6th week

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What do PGCs induce the development of? What happens if there are no PGCs?

testis or ovary; no testis or ovaries

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One PGCs arrive in the primitive gonads, the epithelium of the genital ridges proliferates and penetrates the underlying mesenchyme. What does this form?

primitive sex cords = indifferent gonads

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PGCs carry the Y chromosome with this gene.

SRY gene

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What does the SRY gene lead to the development of?

SRY –> primitive sex cords –> testis/medullary cords

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Where do the testis/medullary cords converge? What are they covered by?

at the rete testis; tunica albuginea

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In the 4th month, what are the testis cords composed of?

PGCs and Sertoli cells

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What are Sertoli cells derived from?

the surface epithelium

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These cells are derived from the original mesenchyme of the gonadal ridges, lie between testis cords, and secrete testosterone.

Interstitial Leydig cells

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When does testosterone production begin?

8th week

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Why is testosterone important?

For the development of the genital ducts and external genitalia

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Testis cords remain solid until (blank)–>canalization–>seminiferous tubules joined at the (blank)–>connected to the (blank) (remaining part of the excretory tubules of the mesonephric system)–>linked to the (blank)–> ductus deferens

puberty; rete testis; ductuli efferentes; mesonephric duct

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If the PGCs carry no Y chromosome, what develops?

ovary

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If PCGs carry no Y chromosome –> sex cords dissociate into (blank)–> (blank) degenerate

(blank) develop from the surface epithelium –> penetrate underlying mesenchyme –> cords split into cell clusters surrounding PGCs –> PGCs become (blank) and surround cell become (blank)

irregular cell clusters; medullary cords

cortical cords; oogonia; follicular cells

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T/F: At the beginning of human development, either male or female development is possible.

True

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Unspecialized gonads and two sets of reproductive ducts persist until what week?

Week 6

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An embryo develops as a male or a female using information from which chromosome? What is the “default”?

Y chromosome; female

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When the (blank) gene is turned on, the testis develop. Once the testis develop, Leydig cells produce (blank) and give rise to the internal male structures. List them. The testis also acts on Sertoli cells to generate (blank) causing the degeneration of the Mullerian ducts (female rudiments). Testosterone can be converted to (blank) which causes the development of external male structures. List them.

SRY; testosterone; epididymis, vas deferns, seminal vesicles, ejaculatory ducts; Anti-Mullerian hormone; DHT; urethra, prostate, penis, scrotum

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What transcription factors take the genital ridge to a biopotential gonad?

SF1
WT1
LHX9

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What transcription factors take a biopotential gonad to an ovary.

DAX1

WNT1

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Discuss sex determination in the female

Genital ridge (primary gonad) affected by SF1, WT1, LHX9 to become a biopotential gonad. DAX1 and WNT4 cause development of ovary, which produces follicles which produce estrogen which induces the female internal genitalia from the mullerian duct

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What transcription factors take a biopotential gonad to the testis?

SRY | SOX9

Discuss sex determination in the male

Genital ridge affected by SF1, WT1, LHX9 and becomes biopotential gonad. Under influence of SRY and SOX9, develops testis. Leydig cells of the testis under influence of SF1 release testosterone. Testosterone enduces Wolfian duct to generate male internal genitalia. Testosterone can be taken to DHT and cause the development of the external male genitalia.

In the male, excretory tubules remain while (blank) regresses

mesonephros

Some of the epigenital tubules are in contact with the rete testis and form up the (blank)

efferent dutules

The caudal portion of the testis contains the paragenital tubules which form up the (blank)

paradidymis

Mesonephric ducts elongate and form what three structures that ultimately empty into the ejaculatory duct.

epididymis; ductus deferens; seminal vesicles

The genital ducts in the male are all derived from the (blank) ducts under the influence of testosterone

mesonephric (Wolffian)

These two sets of ducts exist in both sexes in the earlier development

Mesonephric (Wolffian) and paramesonephric (Mullerian)

Paramesonephric ducts: derived from (blank), cranial end opens to (blank) and caudal end grow and fuse with another one forming what two things?

genital ridges; abdominal cavity; uterine canal; paramesonephric tubercle

Female genital ducts develop from the (blank) ducts.

paramesonephric

In females, the (blank) duct regresses, and the remnants form eopohoron and paroophron.

mesonephric

A small caudal portion of the mesonephric duct remnants in the wall of the uterus or vagina

Gartner's cyst

There are three portions of the paramesonephric ducts. What does the upper portion become? The lower portions fuse and becomes...?

uterine tube; uterine canal

What divides the pelvic cavity into uterorectal and uterovesical pouches?

the broad ligament of the uterus

What does the fused part of the paramesonephric ducts become?

the corpus and cervix of the uterus

What does the mesenchyme differentiate into?

myometrium-->smooth muscle that surrounds the uterus

The vagina has a duel origin: where is the upper portion from? Where is the lower portion from?

the uterine canal; urogenital sinus

epithelial lining of the vaginal sinus and a thin layer of vaginal cells. It is frequently absent (even in virgins) although remnants are commonly present as hymenal caruncula tags

hymen

What is this uterine defect? Uterus didelphys? Uterus arcuatus? Uterus bicornis?

double uterus slightly indented in the middle two uterine horns entering a common vagina

During what week do mesenchyme cells from the primitive streak migrate around the cloacal membrane and generate cloacal folds?

3rd week

The cranial portion of the clocal folds unite to form the (blank). Anteriorly, it forms the (blank) and posteriorly it forms the (blank)

genital tubercle; urethral folds; anal folds

In males, what does the genital tubercle become? In females?

penis; clitoris

In males, what do the the urethral folds become? In females?

in males they fuse and form the urethra; in females there is no fusion and they form the labia minora

In males, what do the genital swellings become? In females?

in males, they fuse and form the scrotum. In females, there is no fusion and they become the labia majora.

Development of male external genitalia depends on (blank) produced by the fetal testis' Leydig cells

androgen

Rapid elongation of the genital tubercle in the male forms up the (blank). The (blank) pulls the urethral fold forward forming a urethral groove, which becomes the urethral plate when lined with epithelium from the endoderm.

phallus; phallus

At the end of the (blank) month, two urethral folds close over the plate and form up the (blank)

3rd; penile urethra

Solid epithelial cord --> (blank) --> urethral outlet of the (blank)

lumen; glans penis

What stimulates the development of the female external genitalia?

estrogen

When the genital tubercle slightly elongates it forms up the (blank). If the urethral folds do not fuse they form up the (blank). Genital swelling forms up the (blank).

clitoris; labia minora; labia majora

Is the genital tubercle larger in the male or female between the 3rd and 4th month? Is this a reliable measure of sex identification?

larger in the female; NO

Incomplete fusion of the urethral folds leading to abnormal openings of the urethra along the inferior penis. Openings can be near the glans, shaft, or base.

hypospadias

What is the incidence of hypospadias? What may be the cause?

3-5/1000; environmental estrogen

A malformation in which the urethra opens on the dorsum of the penis; Occurs as an isolate defect, but frequently associated with exstrophy of the bladder. A lack of mesodermal migration into the region between the umbilicus and genital tubercle, followed by rupture of the thin layer of ectoderm

Epispadias

2.5 standard deviations below average size for the age group; insufficient androgen stimulation caused by hypogonadonism or hypothalamic or pituitary dysfunction

micropenis

genital tubercle splits

double penis

Female, 46, XX, ovaries, uterus Usually caused by congenital adrenal hyperplasia or adrenogenital syndrome. Excessive production of androgens, which masculinizes the external genitalia, causing enlargement of the clitoris to form a penis looking thing and partial fusion of the labia to form a scrotum looking thing

pseudohermaphroditism

Male, 46 XY X-linked recessive disorder Caused by androgen insensitivity --> tissue unresponsive to testosterone due to androgen receptor mutations

testicular feminization

Testes present, MIS/AMH-->paramesonephric system is suppressed so no uterine tubes or uterus, vagina is short and blind

presentation of testicular feminization

The testis develop in the (blank) and descend to the (blank) through the internal ring and the external ring proceeded by the vaginal process that later surrounds each testis as the (blank)

abdomen; scrotum; tunica vaginalis

(blank) attaches to the caudal pole and to the scrotum to assist in the descent

gubernaculum

Cryptochidism

one or both of the testes does not descend

Vaginal process fails to close and intestines pass through rings to scrotum

inguinal hernia

cysts secreting fluid

hydrocele

Yan: Genital System Flashcards

(68 cards)