020 Embryology of the Human Genitourinary Tract

Question 1

The glomerulus, proximal tubule, loop of Henle, and distal tubule are derived from the __.

Answer 1

The glomerulus, proximal tubule, loop of Henle, and distal tubule are derived from the METANEPHRIC MESENCHYME.

Question 2

The remainder of the collecting system is formed from the __.

Answer 2

The remainder of the collecting system is formed from the URETERIC BUD.

Question 3

The __ states that the most lateral and cephalad ureteric orifice arises from the lower pole and may demonstrate reflux whereas the most medial and caudad orifice drains the upper pole and may be associated with a ureterocele.

Answer 3

The WEIGERT-MEYER RULE states that the most lateral and cephalad ureteric orifice arises from the lower pole and may demonstrate reflux whereas the most medial and caudad orifice drains the upper pole and may be associated with a ureterocele.

Question 4

__ produce müllerian-inhibiting substance, which causes regression of the müllerian ducts.

Answer 4

SERTOLI CELLS produce müllerian-inhibiting substance, which causes regression of the müllerian ducts.

Question 5

Testosterone is secreted by the __ and stimulates the wolffian ducts to form the vas deferens and seminal vesicles.

Answer 5

Testosterone is secreted by the LEYDIG CELLS and stimulates the wolffian ducts to form the vas deferens and seminal vesicles.

Question 6

The prostate and bulbourethral glands develop from the __.

Answer 6

The prostate and bulbourethral glands develop from the UROGENITAL SINUS.

Question 7

__ play a critical role in the development of the prostate.

Answer 7

CIRCULATING ANDROGENS play a critical role in the development of the prostate.

Question 8

When 5α-reductase is deficient, __ is severely compromised.

Answer 8

When 5α-reductase is deficient, PROSTATIC GROWTH AND DEVELOPMENT is severely compromised.

Question 9

In the absence of müllerian-inhibiting substance and androgens, the __ degenerate and the müllerian ducts give rise to the fallopian tubes, uterus, and upper two-thirds of the vagina.

Answer 9

In the absence of müllerian-inhibiting substance and androgens, the WOLFFIAN DUCTS degenerate and the müllerian ducts give rise to the fallopian tubes, uterus, and upper two-thirds of the vagina.

Question 10

Boys with spina bifida have a 23% incidence of __.

Answer 10

Boys with spina bifida have a 23% incidence of CRYPTORCHIDISM.

Question 11

If the __ is translocated to an X chromosome, an XX female will have male characteristics.

Answer 11

If the SRY GENE COMPLEX is translocated to an X chromosome, an XX female will have male characteristics.

Question 12

The __ is important for the normal development and growth of the kidney.

Answer 12

The RENIN-ANGIOTENSIN SYSTEM is important for the normal development and growth of the kidney.

Question 13

Circulating androgens and the conversion of testosterone to __ are critical to the normal development of the prostate and male external genitalia.

Answer 13

Circulating androgens and the conversion of testosterone to DIHYDROTESTOSTERONE (DHT) are critical to the normal development of the prostate and male external genitalia.

Question 14

A defect in the __ may result in hypospadias, cryptorchidism, and ambiguous genitalia (disorders of sex development).

Answer 14

A defect in the WT1 GENE may result in hypospadias, cryptorchidism, and ambiguous genitalia (disorders of sex development).

Question 15

Defects in the androgen receptor result in abnormal __ of the external genitalia.

Answer 15

Defects in the androgen receptor result in abnormal MASCULINIZATION of the external genitalia.

Question 16

__ appears to be important for the transit of the testis through the inguinal canal and into the scrotum.

Answer 16

ABDOMINAL PRESSURE appears to be important for the transit of the testis through the inguinal canal and into the scrotum.

Question 17

The embryonic kidneys are, in order of their appearance, the__, the __, and the __. The first two kidneys regress in utero, and the third becomes the permanent kidney.

Answer 17

The embryonic kidneys are, in order of their appearance, the PRONEPHROS, the MESONEPHROS, and the METANEPHROS. The first two kidneys regress in utero, and the third becomes the permanent kidney.

Question 18

Older, more differentiated nephrons are located in the __ part of the kidney near the juxtamedullary region.

Answer 18

Older, more differentiated nephrons are located in the INNER part of the kidney near the juxtamedullary region.

Question 19

__ migrate from the yolk sac along the dorsal mesentery to populate the mesenchyme of the posterior body wall near the 10th thoracic level.

Answer 19

PRIMORDIAL GERM CELLS migrate from the yolk sac along the dorsal mesentery to populate the mesenchyme of the posterior body wall near the 10th thoracic level.

Question 20

__ begin their differentiation in response to the SRY (sex- determining region of the Y chromosome); they begin to secrete MIS, which causes the paramesonephric (müllerian) ducts to regress.

Answer 20

SERTOLI CELLS begin their differentiation in response to the SRY (sex- determining region of the Y chromosome); they begin to secrete MIS, which causes the paramesonephric (müllerian) ducts to regress.

Question 21

Müllerian duct remnants in the male include the __ and the __.

Answer 21

Müllerian duct remnants in the male include the PROSTATIC UTRICLE and the APPENDIX TESTIS.