Exam 1: Embryology of the Reproductive Tract

Question 1

Where does fertilization occur?

Answer 1

Ampulla of the uterine tube

Question 2

________ and ________ do not have oviducts

Answer 2

Dogs and cats

Question 3

What is a gamete?

Answer 3

Oocyte or sperm- Haploid

Question 4

What is a zygote?

Answer 4

Fused gametes- Diploid

Question 5

What are the layers of the blastocyst and what will they

eventually become?

Answer 5

Inner Cell Mass (Embryoblast) - Embryo

Trophoblast- Placenta

Blastocoele- Fluid filled space

Question 6

Which organized cell layer becomes the

skin, eyes, and teeth?

Answer 6

ECTOderm

Question 7

Which organized cell layer becomes the

muscles, skeleton, and most of the repro tract?

Answer 7

MESOderm

Question 8

Which organized cell layer becomes the

gut, respiratory system, and abdominal organs (pancreas, liver)?

Answer 8

ENDOderm

Question 9

The urogenital sinus is an outpouching of

hindgut _______

Answer 9

ENDOderm

Question 10

Primordial germ cells get surrounded by cells of the

primitive gonad and become _______ _______

Answer 10

Sex Cords

Question 11

Germ cells surrounded by sex cords become

_______ in females

and

_______ in males

Answer 11

Granulosa cells (oocyte/follicle) - Female

SERTOLI cells - Male

Question 12

Genetic/Chromosomal sex

is determined at ___________

Answer 12

fertilization

Question 13

In mammals, the heterogametic is the male

but in __________, the heterogametic is the female

Answer 13

BIRDS

Question 14

What are the testis determining genes

responsible for gonadal sex differentiation?

Answer 14

SRY, SOX9

Question 15

What are the ovary determining genes

responsible for gonadal sex differentiation?

Answer 15

RSPO1, WNT

Question 16

Which hormone is responsible for

phenotypic sex differentiation and subsequently

testosterone and dihydrotestosterone production?

Answer 16

AMH (Anti-Mullerian Hormone)

• Causes regression of the mullerian/peramesonephric duct*
• leading to regression of the female tract*

Question 17

SRY testis determining factor is synthesized in

the ________ of the male

Answer 17

sex cord

Question 18

_______ sex cords differentiate into Sertoli Cells

while

________ sex cords degenerate

Answer 18

Medullary sex cords - Sertoli Cells

Cortical sex cords - degenerate

Question 19

________ cells, in addition to the early male gonad

produce Anti-Mullerian Hormone

Answer 19

Pre-Sertoli cells

Question 20

In absence of SRY,

________ sex cords develop into follicles

while

________ sex cords degenerate

Answer 20

Cortical sex cords - follicles

Medullary sex cords - degenerate

Question 21

The paramesonephric duct develops at about

______ weeks in both sexes

Answer 21

6 weeks

Question 22

The urogenital sinus forms as an outpouching of the hindgut

and is continuous with the ________, and forms the bladder

and pelvic urethra which is contacted by the ureters.

Answer 22

Urachus

Question 23

In the indifferent stage of external genetalia formation,

the pair of swellings lateral to the cloaca are called

________ ________

Answer 23

cloacal folds

Question 24

Cranial portion of the cloacal folds fuse to form the

_________ __________

Answer 24

urogenital tubercle

Question 25

The **cloacal folds** fuse to form the **urogenital tubercle** which goes on to become the \_\_\_\_\_\_\_ in males or the \_\_\_\_\_\_\_ in females

Answer 25

penis clitoris

Question 26

How many days into pregnancy are you able to sex a fetus?

Answer 26

60 - 80 days (7th week)

Question 27

The ligamentous cord from gonad to skin that makes its way through the abdominal muscles and ends in the region of the labioscrotal swellings in the 7th week of gestation

Answer 27

Gubernaculum

Question 28

When the gubernaculum reaches the labioscrotal swellings in the 7th week, this turns into the \_\_\_\_\_\_\_ in males and the \_\_\_\_\_\_\_\_ in females

Answer 28

**Processus vaginalis** (males- *the cavity inside the scrotum*) and the **Ovarian ligament** and **round ligament of the uterus** (females)

Question 29

The _______ center of the hypothalamus makes pulses of GnRH which governs transition to puberty in females

Answer 29

TONIC

Question 30

The _______ center of the **hypothalamus** in females has high frequency pulses of GnRH, which superstimulates the **anterior pituitary** to release \_\_\_\_\_\_, the hormone important for initiating ovulation

Answer 30

SURGE center LH

Question 31

Testosterone cross the BBB and is converted to \_\_\_\_\_\_\_\_ which defeminizes the hypothalamus and eliminates the surge center

Answer 31

Estradiol

Question 32

Fetal ovaries produce estradiol, but it does not cross the BBB because it is bound to \_\_\_\_\_\_\_\_\_\_

Answer 32

alpha-fetoprotein

Question 33

In temperature dependent sex determination, phenotypic sex is irreversibly determined mid-incubation during the __________ period

Answer 33

Thermosensitive

Question 34

Disagreement between chromosomal and gonadal sex resulting in varying degrees of male-ness

Answer 34

Sex reversal

Question 35

In XX-sex reversal in **goats**, this condition is linked to hornlessness due to a large genetic deletion

Answer 35

Polled intersex (PIS)

Question 36

This breed of dog has higher incidences of XX-sex reversal

Answer 36

American Cocker Spaniel

Question 37

In Freemartin cows, fusion of allantoic blood vessels results in male and female co-twins that are both \_\_\_\_\_\_, meaning they are composed by cells from 2 different zygotes.

Answer 37

chimeras

Question 38

The daughters of fertile bulls with testicular hypoplasia tend to have this developmental abnormality

Answer 38

Hypoplastic ovaries

Question 39

T/F: **Germinal inclusion cysts** found in the ovulation fossa of mares, can resemble granulosa cell tumors and cause infertility

Answer 39

TRUE

Question 40

These 2 congenital lesions occur in white shorthorns cows with White Heifer Disease.

Answer 40

Persistent hymen and Segmental aplasia (usually means they have only one uterine horn)

Question 41

Failure of fusion of **paramesonephric ducts** can result in a **double cervix**, which is common in _____ but rare in other species

Answer 41

cows

Question 42

Failure of fusion of **paramesonephric ducts** can result in **vaginal cords/septum** which are important in this species

Answer 42

Dogs

Question 43

This condition common in filliies, occurs when the fetal vaginal membrane fails to perforate, which can result in an unbred female horse (filly) displaying signs of foaling.

Answer 43

Imporforate hymen

Question 44

This fundamentally **genetic** condition can result in a 10x greater risk of primary testicular tumors, especially Sertoli Cell Tumors, as well as an increased risk of testicular torsion

Answer 44

Cryptorchidism

Question 45

Which breed of horse is predisposed to Cryptorchidism?

Answer 45

Quarter Horses

Question 46

What is the most common location of a retained testicle in Cryptorchid horses and which testicle is more common?

Answer 46

Abdomen, Left testicle

Question 47

In equines, this type of tumor along with Sertoli Cell tumors can accompany cryptorchidism

Answer 47

Teratoma

Question 48

This breed of bovine is predisposed to testicular hypoplasia

Answer 48

Swedish Red

Question 49

A congenital lesion where the urethra opens on the **ventral** surface of the penis

Answer 49

Hypospadias

Question 50

In this congenital disorder, seen in humans but rare in domestic animals, the urethra opens on the **dorsal** surface of the penis

Answer 50

Epispadias