Quiz 3

Question 1

The descent of the testes occur in _____ stages. This phenomenon depends on the proper growth and regression of the ligamentous cord structure known as _____. At least in pigs, it has been proposed that a small peptide (protein) called _____ that is produced by the testis induces the growth of this ligamentous cord.

Answer 1

3
gubernaculum
Insulin like factor (Insl-3)

Question 2

Name the three embryonic germ layers and provide one organ that originate from each germ layer.

Answer 2

endoderm - liver
mesoderm - reproductive tract (uterus)
ectoderm - skin

Question 3

The primordial germ cells migrate from the yolk sac and reside in a specific region called _____. The primordial germ cells that do not reside in that region will _____. The liver protein that binds estradiol in fetal blood is _____. Binding of these proteins prevents the estradiol to penetrate the _____ in the brain and as a result _____ of the hypothalamus remains intact. Therefore, brain defiminization does not occur in the female fetus.

Answer 3

genital ridge 
die 
alpha fetaprotein 
brain blood barrier 
surge center GNRH

Question 4

In genetic sexual differentiation the gene that is responsible for male development is _____. This gene expresses a substance (factor) called _____ that controls the pathway towards differentiation of the gonad to male reproductive system. This factor causes the development of Sertoli cells. Sertoli cells are capable of secreting _____, which causes the regression of paramesonephric/mullerian ducts. The Leydig cells; however, produce a potent testosterone that is called ______.

Answer 4

Sry
testis determining factor (TDF)
anti-mullerian hormone (AMH)
5 alpha dihydrotestosterone

Question 5

True or False
While Leydig cells are responsible for anti-mullerian hormone production, Sertoli cells are responsible for testosterone production.

Answer 5

false

Question 6

True or False
Mesonephric ducts, also called mullerian ducts give rise to the oviduct and uterus whereas paramesonephric ducts give rise to efferent ducts and epididymis.

Answer 6

false

Question 7

True or False
Defeminization of Hypothalamus surge center is due to conversion of testosterone to estradiol by aromatase enzyme in the hypothalamus.

Answer 7

true

Question 8

True or False

Mesonephros is the fully functional kidney

Answer 8

false

Question 9

Klinefelter’s syndrome

Answer 9

XXY, infertile, testicular hypoplasim

Question 10

Turner’s syndrome

Answer 10

XO, infertile, inactive ovaries

Question 11

What are the sex chromosomes in birds?

Answer 11

male - ZZ

females - ZW

Question 12

What would happen if we stopped the activity of aromatase enzyme in the hypothalamus in the early stage of male development?

Answer 12

testosterone would not be converted to estradiol in the hypothalamus and the surge center would stay intact.

Question 13

What is the role of Gubernaculum?

Answer 13

helps the testes descend into the scrotal sac

Question 14

What hormone is responsible for growth of gubernaculum?

Answer 14

Insulin like factor 3

Question 15

What are the 3 morphologically distinct renal systems (kidneys) in order?

Answer 15

1. pronephros
2. mesonephros
3. metanephros

Question 16

What would happen during embryogenesis and sexual differentiation if we eliminated the Sry Gene from the sex chromosome?

Answer 16

there would be no TDF, and no testes, without testes you wouldn’t have sertoli cells, without sertoli cells there would be no AMH, without AMH the mullerian tract would develop

Question 17

Name the three distinct phases of testes descent in order.

Answer 17

1. growth of body away from the testes
2. growth of the gubernaculum
3. regression of the gubernaculum

Question 18

True or False

While primitive sex cord is where TDF is produced, Leydig cells are responsible for testosterone production.

Answer 18

true

Question 19

True or False
Paramesonephric ducts, also called Mullerian ducts give rise to the oviduct and uterus whereas mesonephric ducts give rise to efferent ducts and epididymis.

Answer 19

true

Question 20

True or False
Defeminization of hypothalamus surge center is due to conversion of estradiol to testosterone by aromatase enzyme in the hypothalamus.

Answer 20

false

Question 21

True or False
Binding of alpha-fetoprotein with testosterone prevent the molecule from penetrating the blood brain barrier and thus the hypothalamic surge center remains intact

Answer 21

false

Question 22

If you castrate a young animal (fetal stage), male or female, which system will develop?

Answer 22

female

Question 23

Transplant testis to female embryo which system will develop?

Answer 23

male