16 - External Genitaliax

3rd week

At which week of life are the cloacal folds formed?

Urethral fold

Anterior subdivision of the cloacal fold

Anal Fold

Posterior subdivision of the cloacal fold

Genital Tubercle

This is the union of folds cranial to the cloacal membrane

Genital swellings

This is a pair of elevation visible on each side of the urethral folds

Scrotum

Male genital swelling

Labia majora

Female genital swelling

Androgens

The external genitalia in males are formed under the influence of what?

Phallus

This structure is formed by the rapid elongation of the genital tubercle

T

T/F: During elongation, the phallus pulls the urethral folds forward to form the lateral walls of the urethral groove

F; It does not reach the glans

T/F: The urethral groove extends along the ventral part of the phallus until the glans

Urethral Plate

Epithelial lining of the urethral groove forms what structure?

Endoderm

The urethral plate originates from which cell layer?

Penile Urethra

This structure is formed when the urethral folds close over the urethral plate

T

T/F: The canal does not extend up to the tip of the phallus during the 3rd month

End of 3rd month

When is the penile urethra developed?

4th month

When is the most distal part of the urethra formed?

Ectoderm

The most distal portion of the urethra originates from what cell layer?

Caudally

In what direction do the male scrotal swellings move in during development?

Deep inguinal ring

The testes enters the inguinal canal via the?

Superficial inguinal ring

The testes exits the inguinal canal via the?

End of 2nd month

At what month does the urogenital mesentery attach the testis and the mesonephros to the posterior abdominal wall

T

T/F: The gubernaculum forms in females but remain rudimentary

Outgrowth of the extra-abominal portion of the gubernaculum

This factor will lead to the intra-abdominal migration of the testis

Increase in intra-abdominal pressure

This factor will lead to the passage of the testis through the inguinal canal

Regression of the extra-abdominal portion of the gubernaculum

This factors will complete the movement of the testis into the scrotum

12th week

When does the testis reach the inguinal region

28th week

When does the testis migrate through the inguinal canal

33rd week

When does the testis reach the scrotum

T

T/F: The blood supply of the testis from the aorta is retained

Processus vaginalis

This is the evagination of the peritoneum of the abdominal cavity on each side of the midline into the ventral abdominal wall

Internal spermatic fascia

Covering of the testis derived from the transversalis fascia

Cremasteric fascia and muscle

Covering of the testis derived from the IO Aponeurosis

External Spermatic Fascia

Covering of the testis derived from the EO Aponeurosis

Clitoris

The genital tubercle in females forms what structure

Labia minora

The urethral folds in females forms what structure

Vestibule

The urogenital groove in females forms what structure

Suspensory ligament of the ovary

The cranial genital ligament in females gives rise to what structure?

Round ligament of the ovary and uterus

The caudal genital ligament in females gives rise to what structure?

F; Round ligament of the uterus

T/F: The round ligament of the ovary extends into the labia majora

Below the rim of the true pelvis

Where do the ovaries settle?

F; Ventral penis

T/F: Incomplete fusion of urethral folds leads to abnormal opening along the dorsal penis

Hypospadias

This defect is caused by the incomplete or complete failure of fusion of the urethral folds in males

Epispadias

This defect is characterized by seeing the urethral meatus at the dorsum of the penis and is most often associated with exstrophy of the bladder and abnormal closure of ventral body wall

Micropenis

This is caused by an insufficient androgen stimulation for external genitalia growth

Bifid penis

This defect is caused by the splitting of the genital tubercle

Ambiguous Genitalia

This disorder is characterized as individual having external genitalia with characteristics of both sexes

Ovotesticular disorders

This disorder is characterized by the presence of both ovarian and testicular tissue

46, XX Disorder

This disorder is characterized as females that are exposed to excessive amounts of androgen that masculinize the external genitalia

Isolated deficiency of MIS

This disorder is characterized by a normal male genitalia but with varying degrees of remnants from the mullerian system due to MIS not being produced

Androgen Insensitivity Syndrome (AIS)

This disorder is characterized by a lack of androgen receptors or failure of tissues to respond to receptor-dihydrotestosterone complexes

5-a-reductase deficiency

This disorder is characterized by the inability to convert testosterone to dihydrotestosterone due to a lack of a reductase enzyme leading to hypospadias in males and clitoromegaly in females

47, XXY

Karyotype of Klinefelter syndrome

Nondisjunction of the XX homologues

Most causative factor of Klinefelter syndrome

Gonadal Dysgenesis

This disorder is characterized by phenotypically female patients with absence of oocytes and streak gonads

Pure Gonadal Dysgenesis (Swyer Syndrome)

This results from point mutations or deletions in the SRY gene that eliminates its function leading to females that do not menstruate nor develop secondary sexual characteristics at puberty

45, X

Karyotype of turner’s syndrome

Turner’s syndrome

This disorder is characterized by a patient with short stature, webbed neck, high-arched palate, shield-like chest, and inverted nipples

Cryptorchidism

This condition is caused by the failure of one or both testes to descend to the scrotum

Hydrocele

This is caused by irregular obliteration of the processus vaginalis leading to the accumulation of fluids in cysts

Congenital indirect hernia

This is caused by a patent processus vaginalis leading to the descent of intestinal loops into the scrotum