Introduction cont. (Chapwanya) Flashcards

1
Q

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

A

The polar body

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2
Q

In embryonology what is the most totipotent cell?

A

Zygote

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3
Q

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?

A

Mesoderm- gonads, uterus, and accessory sex glands

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

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4
Q

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

A

Mesoderm and Ectoderm

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5
Q

What part of a developing embryo becomes the placenta?

A

Blastocoel

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6
Q

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

a. Chorion, Amnion
b. Amnion, Chorion

A

b. Amnion, Chorion

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

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7
Q

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

A

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

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8
Q

Match the gestation length to the species:

Dog

Pig

Sheep

Cow

285 days

147 days

62 days

114 days

A

Dog: 62 days

Pig: 114 days

Sheep: 147 days

Cow: 285 days

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9
Q

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

A

Sex determination

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10
Q

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

A

Differentiation

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

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11
Q

What is the chromosomal complement of an organism?

A

Karyotype

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12
Q

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

A

Genotype

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13
Q

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.

A

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.

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14
Q

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

A

At fertilization (determined by sperm contribution)

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15
Q

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

A

Male

Sry gene induces testes formation

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16
Q

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?

A

Mesonephric ducts (Wolffian ducts) -> present in males

Paramesonephric ducts (Muellerian ducts)->present in females

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17
Q

What are the 3 developmental stages of the kidney?

A

Pronephros -> Mesonephros -> Metanephros

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18
Q

What hormone does the Sry gene cause the development of?

A

Testosterone

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19
Q

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

A

Anti-Muellerian hormone (AMH)

Males

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20
Q

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?

A

Dihydrotestosterone (DHT)

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21
Q

______ (Male/Female) development is the default.

A

Female

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22
Q

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

A

Retro-peritoneal position

Attached caudally ot the ligametous gubernaculum

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23
Q

What controls the transabdominal phase of testicular descent?

A

Insulin like growth factor 3 (Insl 3)

And its receptor (Lgr8)

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24
Q

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?

A

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

Androgens

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25
Q

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

A

Tail of the epididymus

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26
Q

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

A

Prostate

Bulboureteral

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27
Q

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

A

Musculovascular penis (with os penis)

Only prostate

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28
Q

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

A

Bulbourethral

Prostate

Vesicular gland

No ampulla

Fibroelastic penis

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29
Q

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

A

Bulbourethral

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30
Q

Which species ejaculated the most semen when mating?

A

Porcine (the boar)

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31
Q

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.

A

Arterial

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32
Q

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

A

Spermatic cords (37C)

Ventral scrotum (31C)

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33
Q

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

A

The sperm reserves in the distal epididymal tail is depleted

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34
Q

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

A

Head of the epididymus

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35
Q

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

A

Body of the epididymus

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36
Q

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

A

Vesicular glands

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37
Q

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

A

Felines

Bovine

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38
Q

The penis of which species have a sigmoid flexure?

A

Equine

Bovine

Porcine

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39
Q

Which species has a mushroom-shaped glans penis?

A

Equine

40
Q

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

A

Canine

41
Q

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

A

Caudally

42
Q

Whose penis is this?

A

Opossum

“Double delight”

43
Q

Which 2 hormones cause defeminization?

A

Testosterone

AMH

44
Q

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

A

Alpha-FP (Fetoprotein)

45
Q

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

A

Threshold body weight (Highlighted)

Nutrition

Environmental cues

Social cues

Photoperiod

Genetics

46
Q

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

A

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

47
Q

What is the average age of puberty in bovines?

A

11 months - Bovines

48
Q

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

A

Stallions - 14 months

Mares- 18 months

49
Q

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

A

Dogs: 6-12 mo

Cats: 5-9 mo

50
Q

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

A

Llama

51
Q

Leydig cells are analogous to _________ in females.

Stertoli cells are analogous to _______ in females.

A

Theca interna

Granulosa cells

52
Q

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

A

LH (glycoprotein)

53
Q

What acts on Sertoli cells to stimulate spermatogenesis?

A

FSH (glycoprotein)

54
Q

What does testosterone cause in systemic circulation?

A

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

55
Q

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

A

Inhibin

Sertoli cells

56
Q

Where does spermatogenesis occur and what does it produce?

A

Seminiferous tubules

Spermatozoa

57
Q

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

A

Mitotic

58
Q

At which phase does transformation from spermatid to spermatozoa occur?

A

Differentiation phase (Spermiogenesis)

59
Q

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

A

13.5 days

61 days (4.5 cycles)

60
Q

In which species is spermatogenesis the shortest?

Bull

Ram

Boar

Stallion

A

Boar (39 days)

Bull= 61d, Ram=47d, Stallion=55d

61
Q

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

A

Equine

Camelid

62
Q

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

A

Bovine

Ovine

Caprine

Canine

Cervid

63
Q

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

A

Porcine

64
Q

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

A

Seminal plasma

65
Q

What are the 2 results of sperm capacitation?

A

Hyper-activated sperm in the oviduct (ampulla)

Unmasking of ZP (zona pellucida)binding sites

66
Q

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

A

Acrosomal reaction

Penetration of the ZP

67
Q

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

A

Oocute plasma membrane - Vitelline membrane

68
Q

Where does fertilization occur in the cow?

A

Ampullaisthmic junction of the oviduct

69
Q

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

A

Syngamy

Formation of the zygote

70
Q

What are the 3 barriers to fertilization?

A

Cumulus cells

Zona pellucida

Oocyte membrane (oolemma)

71
Q

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

A

False, MONOspermy is the norm

72
Q

What does polyspermy result in?

A

Triploid nucleis (XXX, XXY)

Multiple mitotic spindles

Embryo death

73
Q

What is the primary block to polyspermy?

A

Zona pellucida

74
Q

What is the term for a 16+ cell embryo?

A

Morula

75
Q

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?

A

4 days

Horses- 6 days

Dogs- 8 days

76
Q

What is the term for a monozygotic twin? Dizygotic?

A

Mono= Identical

Di= Fraternal

77
Q

Cow or Horse?

Blastocyst is filamentous

Blastocyst remains spherical

A

Cow= Filamentous

Horse= Spherical

78
Q

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

A

4 (2 in each horn)

Estradiol

79
Q

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

A

Maternal Recognition of Pregnancy (MPR)

80
Q

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

A

Canines

Felines

81
Q

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

A

Interferon tau (IFN-t)

Elongation

Oxytocin

Also promotes protein synthesis by uterine glands

82
Q

What is “spacing” and in which species does it occur?

A

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

Porcine

83
Q

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?

A

Those in the other horn have died/been aborted

84
Q

What is the MRP in the mare?

A

PGE2 production by the embryo

85
Q

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

A

Day 12-14

Day 16

86
Q

What is the functional unit of the placenta?

A

Chorionic villi

87
Q

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

A

6

Sow, Mare, Camelid, Cow, Ewe, Doe

88
Q

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

A

5

Canine, Feline

89
Q

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

A

4

Primates, Rodents

90
Q

Which species have zonary placentas?

A

Feline

Canine

91
Q

Which species have convex cotyledonary placenta?

A

Bovine

Giraffe

92
Q

Which species have concave cotyledonary placenta?

A

Ovine

Caprine

93
Q

What are the 4 signs of pregancy in a cow?

A

Membrane slip (Amniotic vesicle)

Presence of fetus

Fetal membranes (chorio-allantoic membrane)

Placentomes

94
Q

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

A

Equine chorionic gonadotropin (eCG)

95
Q

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

A

Cow

Ewe/sheep

Mare