Introduction cont. (Chapwanya)

Question 1

What part of a mature oocyte must be extruded for normal chromosome numbers to develop?

Answer 1

The polar body

Question 2

In embryonology what is the most totipotent cell?

Answer 2

Zygote

Question 3

Which part of the immature embryo will differentiate primarily to the gonads, uterus, and accessory sex glands? Which part will differentiate primarily into the vagina, vestibule, penis, clitoris and mammary glands?

Answer 3

Mesoderm- gonads, uterus, and accessory sex glands

Ectoderm- vagina, vestibule, penis, clitoris and mammary glands

Question 4

Which 2 parts of the developing embryo must link up properly for a functional reproductive system?

Answer 4

Mesoderm and Ectoderm

Question 5

What part of a developing embryo becomes the placenta?

Answer 5

Blastocoel

Question 6

During development, the ______ is closest to the embryo while the _____ is closest to the uterus.

a. Chorion, Amnion
b. Amnion, Chorion

Answer 6

b. Amnion, Chorion

During development, the AMNION is closest to the embryo while the CHORION is closest to the uterus.

Question 7

Why does the brain develop early during the course of embryology?

Answer 7

It is required to coordinate further development of the embryo/fetus

Question 8

Match the gestation length to the species:

Dog

Pig

Sheep

Cow

285 days

147 days

62 days

114 days

Answer 8

Dog: 62 days

Pig: 114 days

Sheep: 147 days

Cow: 285 days

Question 9

What is a system that determines the sexual characteristics of an organim which generally consists of genetic or hormonal parameters?

Answer 9

Sex determination

Question 10

What is the process whereby a group of unspecialized cells develop into a functional, recognizable group of cells that have a common function?

Answer 10

Differentiation

(e.g. Sex differentiation- male vs female repro tract)

Question 11

What is the chromosomal complement of an organism?

Answer 11

Karyotype

Question 12

What is the term that describes the alleles genetic constitution of an individual?

Answer 12

Genotype

Question 13

A _____ is produced by the fusion of 2 different zygotes in a single embryo. A _____ is an individual with 2 different cell lines that originated from that same individual.

Answer 13

Chimera

Mosaic

A CHIMERA is produced by the fusion of 2 different zygotes in a single embryo. A MOSAIC is an individual with 2 different cell lines that originated from that same individual.

Question 14

When is the chromosomal sex (i.e. the karyotype) of an individual determined?

Answer 14

At fertilization (determined by sperm contribution)

Question 15

What sex will an individual be if the Sry gene is present?

Answer 15

Male

Sry gene induces testes formation

Question 16

Which ducts regress in females and form the epididymis and ductus deference? Which ducts regress in males and form the uterus, oviducts, and cranial vagina?

Answer 16

Mesonephric ducts (Wolffian ducts) -> present in males

Paramesonephric ducts (Muellerian ducts)->present in females

Question 17

What are the 3 developmental stages of the kidney?

Answer 17

Pronephros -> Mesonephros -> Metanephros

Question 18

What hormone does the Sry gene cause the development of?

Answer 18

Testosterone

Question 19

Which hormone induces the degeneration of the paramesonephric duct? In which sex does this occur?

Answer 19

Anti-Muellerian hormone (AMH)

Males

Question 20

Which highly active and effective hormone must penetrate the brain of a developing embryo in order for the penis, scrotum and accessory sex glands to develop?

Answer 20

Dihydrotestosterone (DHT)

Question 21

______ (Male/Female) development is the default.

Answer 21

Female

Question 22

Before testicular descent occurs, where do the testes lie and how are they attached?

Answer 22

Retro-peritoneal position

Attached caudally ot the ligametous gubernaculum

Question 23

What controls the transabdominal phase of testicular descent?

Answer 23

Insulin like growth factor 3 (Insl 3)

And its receptor (Lgr8)

Question 24

What is responsible for the mechanical movement of the testes into the inguinal canal during the inguinal-scrotal phase of testicular descent? What is the chemical factor involved?

Answer 24

Rapid growth of the gubernaculum in the scrotal region followed by shrinkage which pulls the testes deeper into the scrotum

Androgens

Question 25

Where is sperm with the potential for fertilization located (i.e. the sperm that is ejaculated)?

Answer 25

Tail of the epididymus

Question 26

Which accessory sex glands do the camelid and the cat have?

Answer 26

Prostate Bulboureteral

Question 27

What type of penis and which accessory sex gland(s) does the dog have?

Answer 27

Musculovascular penis (with os penis) Only prostate

Question 28

Which accessory sex glands does the boar have? What type of penis does he have?

Answer 28

Bulbourethral Prostate Vesicular gland *No ampulla* Fibroelastic penis

Question 29

Which of the 4 accessory sex glands does the bull not have?

Answer 29

Bulbourethral

Question 30

Which species ejaculated the most semen when mating?

Answer 30

Porcine (the boar)

Question 31

Warm _______ (arterial/venous) blood is cooled on its way to the testis so that a 6 degree (C) temperature gradient exists between the body and the testes.

Answer 31

Arterial

Question 32

Where is the warmest temperature region of the testicles? Where is the coolest region?

Answer 32

Spermatic cords (37C) Ventral scrotum (31C)

Question 33

What happens if there are frequent sequential ejaculates within one day?

Answer 33

The sperm reserves in the distal epididymal tail is **depleted**

Question 34

In which part of the epididymus are sperm non-motile, non-fertile and have low disulfide crosslinking?

Answer 34

Head of the epididymus

Question 35

When sperm reach which location are they able to bind to oocytes?

Answer 35

Body of the epididymus

Question 36

Which accessory glands of the stallion are most commonly affected by infection?

Answer 36

Vesicular glands

Question 37

Which 2 species have the ability for rapid ejaculation and erection?

Answer 37

Felines Bovine

Question 38

The penis of which species have a sigmoid flexure?

Answer 38

Equine Bovine Porcine

Question 39

Which species has a mushroom-shaped glans penis?

Answer 39

Equine

Question 40

Which species has a substantial glans penis which is divided into the bulbus glandis proximally and the pars longa glandis distally?

Answer 40

Canine

Question 41

In which direction are the keratinised papillae of a tom cat penis directed?

Answer 41

Caudally

Question 42

Whose penis is this?

Answer 42

Opossum ## Footnote *"Double delight"*

Question 43

Which 2 hormones cause defeminization?

Answer 43

Testosterone AMH

Question 44

In the female brain, what prevents E2 from entering the brain allowing for the development of a surge center (i.e. feminization)?

Answer 44

Alpha-FP *(Fetoprotein)*

Question 45

What are some factors on which the development of the specific hypothalamic nuclei capable of releasing GnRH depend?

Answer 45

**Threshold body weight** *(Highlighted)* Nutrition Environmental cues Social cues Photoperiod Genetics

Question 46

T/F: The age at which a female reaches puberty does not affect her lifetime productivity.

Answer 46

False, the earlier she reaches puberty the more productive she will be

Question 47

What is the average age of puberty in bovines?

Answer 47

11 months - Bovines

Question 48

Do stallions or mares reach puberty earlier? What the is average age for each sex?

Answer 48

Stallions - 14 months Mares- 18 months

Question 49

What is the average age of puberty in dogs? Cats?

Answer 49

Dogs: 6-12 mo Cats: 5-9 mo

Question 50

Which species reaches puberty between 2-4 years of age and is generally not breed until close to 3 years of age?

Answer 50

Llama

Question 51

Leydig cells are analogous to _________ in females. Stertoli cells are analogous to _______ in females.

Answer 51

Theca interna Granulosa cells

Question 52

What acts on Leydig cells and stimulates the production of testosterone?

Answer 52

LH *(glycoprotein)*

Question 53

What acts on Sertoli cells to stimulate spermatogenesis?

Answer 53

FSH *(glycoprotein)*

Question 54

What does testosterone cause in systemic circulation?

Answer 54

**Negative feedback** to **decrease GnRH** which causes a **decrease in FSH and LH**

Question 55

What negatively feeds back on the anterior pituitary to selectively suppress FSH? Where is it produced?

Answer 55

Inhibin Sertoli cells

Question 56

Where does spermatogenesis occur and what does it produce?

Answer 56

Seminiferous tubules Spermatozoa

Question 57

What type of divisions occur during the proliferation phase of spermatogenesis?

Answer 57

Mitotic

Question 58

At which phase does transformation from spermatid to spermatozoa occur?

Answer 58

Differentiation phase (Spermiogenesis)

Question 59

How long is the bull's semineferous epithelium cycle? How long is spermatogenesis?

Answer 59

13.5 days 61 days *(4.5 cycles)*

Question 60

In which species is spermatogenesis the shortest? Bull Ram Boar Stallion

Answer 60

Boar (39 days) ## Footnote *Bull= 61d, Ram=47d, Stallion=55d*

Question 61

In which species is sperm deposited in the uterus during natural mating?

Answer 61

Equine Camelid

Question 62

In which species is sperm deposited in the anterior vagina during natural mating?

Answer 62

Bovine Ovine Caprine Canine *Cervid*

Question 63

In which species is semen deposited into the cervix during natural mating?

Answer 63

Porcine

Question 64

What coats the sperm with proteins that must be removed for maximum fertility?

Answer 64

Seminal plasma

Question 65

What are the 2 results of sperm capacitation?

Answer 65

Hyper-activated sperm in the oviduct (ampulla) Unmasking of ZP *(zona pellucida)*binding sites

Question 66

What occurs after sperm binds to the ZP? What follows?

Answer 66

Acrosomal reaction Penetration of the ZP

Question 67

What is the membrane to which the sperm head attaches during the cortical reaction?

Answer 67

Oocute plasma membrane - **Vitelline membrane**

Question 68

Where does fertilization occur in the cow?

Answer 68

Ampullaisthmic junction of the oviduct

Question 69

What is the fusion of male and female pronuclei termed? What does this fusion lead to?

Answer 69

Syngamy Formation of the zygote

Question 70

What are the 3 barriers to fertilization?

Answer 70

Cumulus cells Zona pellucida Oocyte membrane (oolemma)

Question 71

T/F: Polyspermy is the norm and restores the diploid chromosome number.

Answer 71

False, **MONO**spermy is the norm

Question 72

What does polyspermy result in?

Answer 72

Triploid nucleis (*XXX, XXY)* Multiple mitotic spindles Embryo death

Question 73

What is the primary block to polyspermy?

Answer 73

Zona pellucida

Question 74

What is the term for a 16+ cell embryo?

Answer 74

Morula

Question 75

How long does it take for the zygote to reach the uterus in cows and most species? In which species does it take longer than this?

Answer 75

4 days Horses- 6 days Dogs- 8 days

Question 76

What is the term for a monozygotic twin? Dizygotic?

Answer 76

Mono= Identical Di= Fraternal

Question 77

Cow or Horse? Blastocyst is filamentous Blastocyst remains spherical

Answer 77

Cow= Filamentous Horse= Spherical

Question 78

How many embryos are required in a sow for a pregnancy to continue? What is the MRP?

Answer 78

4 (2 in each horn) Estradiol

Question 79

What must occur before luteolysis and maintains a high level of P4?

Answer 79

Maternal Recognition of Pregnancy (MPR)

Question 80

Which 2 species do not require pregnancy recognition factors for the pregnancy to continue?

Answer 80

Canines Felines

Question 81

What is the MRP in ruminants? What does it cause in the embryo? The formation of which hormone receptor does it inhibit?

Answer 81

Interferon tau (IFN-t) Elongation Oxytocin *Also promotes protein synthesis by uterine glands*

Question 82

What is "spacing" and in which species does it occur?

Answer 82

Uterus' ability to count concepti and can ensure that the same number are in each horn Porcine

Question 83

What does it indicate if you ultrasound a sow later in pregnancy and note that there are embryos in one horn but not the other?

Answer 83

Those in the other horn have died/been aborted

Question 84

What is the MRP in the mare?

Answer 84

PGE2 production by the embryo

Question 85

When does blastocyst trans-uterine migration occur in the mare? When does fixation occur?

Answer 85

Day 12-14 Day 16

Question 86

What is the functional unit of the placenta?

Answer 86

Chorionic villi

Question 87

How many tissue layers are between maternal and fetal blood in species with an **epitheliochorial** placenta? What species are these?

Answer 87

6 Sow, Mare, Camelid, Cow, Ewe, Doe

Question 88

How many tissue layers are between maternal and fetal blood in species with an **endotheliochornial** placenta? What species are these?

Answer 88

5 Canine, Feline

Question 89

How many tissue layers are between maternal and fetal blood in species with an **hemochorial** placenta? What species are these?

Answer 89

4 Primates, Rodents

Question 90

Which species have zonary placentas?

Answer 90

Feline Canine

Question 91

Which species have convex cotyledonary placenta?

Answer 91

Bovine Giraffe

Question 92

Which species have concave cotyledonary placenta?

Answer 92

Ovine Caprine

Question 93

What are the 4 signs of pregancy in a cow?

Answer 93

Membrane slip (Amniotic vesicle) Presence of fetus Fetal membranes (chorio-allantoic membrane) Placentomes

Question 94

What serves as the stimulus to the primary CL and stimulates accessory CLs in the mare?

Answer 94

Equine chorionic gonadotropin (eCG)

Question 95

In which species does the placenta take over as the primary source of P4 (from the ovary)?

Answer 95

Cow Ewe/sheep Mare