Section 1: Ovulation to Parturition

Question 1

when does the zona pellucida surround the oocyte?

Answer 1

secondary follicle

Question 2

is the primary follicle or primordial follicle more developed?

Answer 2

primary follicle more developed

Question 3

female is born with a lifetime supply of ____________________________

Answer 3

primordial and primary follicles

Question 4

what makes a follicle an antral follicle or a tertiary follicle?

Answer 4

has cavity filled with follicular fluid

Question 5

what are the three distinct layers of antral follicles?

Answer 5

theca externa
theca interna
granulosa cell layer

Question 6

how does a corpus hemorrhagicum form?

Answer 6

following ovulation of dominant antral follicle: antrum collapses and fills with blood

Question 7

what cells in the corpus luteum produce progesterone?

Answer 7

granulosa cells/large luteal cells
theca interna cells/small luteal cells

Question 8

what is the corpus albicans?

Answer 8

remnant of lysed corpus luteum

Question 9

what is the neural control center for reproductive hormones?

Answer 9

hypothalamus

Question 10

what does the tonic center in the hypothalamus secrete?

Answer 10

gonadotropin releasing hormone (GnRH)
small pulses over a prolonged period of time

Question 11

what is the surge center of the hypothalamus responsible for?

Answer 11

preovulatory release of gonadotropin releasing hormone

Question 12

what does the paraventricular nucleus of the hypothalamus produce?

Answer 12

oxytocin

Question 13

what does the anterior pituitary (adenohypophysis) release in response to gonadotropin releasing hormone?

Answer 13

follicle stimulating hormone
luteinizing hormone
prolactin

Question 14

where does the paraventricular nucleus release oxytocin?

Answer 14

posterior pituitary (neurohypophysis): no portal system

Question 15

how does the corpus luteum form?

Answer 15

luteinization

Question 16

a cohort of small, antral follicles grow and produce estradiol and _________ in response to tonic levels of ______________

Answer 16

inhibin
FSH and LH

Question 17

what is the point of deviation?

Answer 17

one or several (polyovulatory species) follicles become dominant of wave
rest of cohort undergoes atresia

Question 18

what hormones are important in luteolysis?

Answer 18

PGF2alpha and oxytocin

Question 19

in males, __________________________ is released from the hypothalamus every several hours in short, intermittent bursts

Answer 19

gonadotropin releasing hormone

Question 20

what stimulates leydig cells to produce testosterone?

Answer 20

luteinizing hormone release

Question 21

what organ is needed for luteolysis?

Answer 21

uterus

Question 22

in whom may diestral ovulations in the face of high progesterone occur?

Answer 22

mare

Question 23

what leads to the preovulatory surge of luteinizing hormone?

Answer 23

progesterone levels fall
estradiol reaches threshold level
surge of gonadotropin releasing hormone from surge center of hypothalamus

Question 24

what ensures that a high proportion of PGF2alpha produced by the endometrium will be transported directly to the ovary and corpus luteum without being diluted in the systemic circulation?

Answer 24

vascular countercurrent exchange mechanism

Question 25

what does luteolysis mark?

Answer 25

end of luteal phase abrupt cessation of progesterone production and structural regression of the corpus luteum to form corpus albicans

Question 26

what are the stages of spermatogenesis?

Answer 26

spermatocytogenesis meiosis spermiogenesis spermiation

Question 27

what happens in spermatocytogenesis?

Answer 27

spermatogonia undergo a series of mitotic divisions to become primary spermatocytes

Question 28

what is produced in the meiosis step of spermatogenesis?

Answer 28

spermatids

Question 29

what happens during spermiogenesis?

Answer 29

spermatids are transformed into spermatozoa

Question 30

how long does spermatogenesis require?

Answer 30

5 to 9 weeks

Question 31

true/false: spermatogenesis occurs in waves so that sperm is being continuously produced

Answer 31

true

Question 32

when does maturation of the sperm occur?

Answer 32

as they travel the length of the convoluted tubule

Question 33

once ovulated, how long do oocytes remain viable?

Answer 33

12 hours to a day or so

Question 34

where does fertilization take place?

Answer 34

ampulla of the oviduct

Question 35

how long does the fertilized oocyte remain in the oviduct before descending into the uterus?

Answer 35

days: 3-6

Question 36

how many sperm are ejaculated into the tract and how many reach the oviduct?

Answer 36

millions to billions small percent: tens to hundreds

Question 37

what is the life span of sperm in the female tract?

Answer 37

48 hours

Question 38

sperm must undergo _____________ before they can fertilize the oocyte

Answer 38

capacitation

Question 39

what does capacitation involve?

Answer 39

loss of proteins from sperm plasma membrane that inhibit acrosome reaction

Question 40

when does capacitation occur?

Answer 40

within a few hours of contact with female tract

Question 41

what initiates the acrosome reaction in the sperm?

Answer 41

binding to zona pellucida

Question 42

what releases the acrosomal enzymes allowing the sperm to digest its way through the zona pellucida?

Answer 42

external plasma membrane of the sperm fuses with the outer acrosomal membrane

Question 43

what is the final step of fertilization?

Answer 43

fusion of male and female pronuclei and resulting zygote begins embryogenesis

Question 44

how do the ewe and cow prevent luteolysis and the initiation of a new cycle after fertilization?

Answer 44

blastocyst produces specific proteins in the interferon class

Question 45

what specific proteins does the blastocyst in the ewe and cow produce to prevent luteolysis after fertilization?

Answer 45

ovine trophoblastic protein 1: now ovine interferon tau bovine trophoblastic protein 1: now bovine interferon tau

Question 46

what is produced in the sow to signal for maternal recognition of pregancy?

Answer 46

estradiol

Question 47

how does estradiol serve as the signal for maternal recognition of pregnancy in the sow?

Answer 47

reroutes PGF2alpha secretion away from the submucosal capillaries and toward the uterine lumen: little access to circulation

Question 48

how many stages of parturition are there?

Answer 48

three

Question 49

after the point of deviation, why does the rest of the cohort undergo atresia?

Answer 49

lack LH receptors and require FSH to grow decreasing FSH concentrations

Question 50

how do high progesterone levels impact the preovulatory surge?

Answer 50

inhibit it: if during luteal phase

Question 51

how long does it take from initiation of spermatogenesis until those sperm appear in the ejaculate?

Answer 51

average of two months

Question 52

there must be at least ___________________ present in each horn of the uterus in the sow for pregnancy to be maintained

Answer 52

two conceptuses

Question 53

why is "attachment" the preferred term for placentation in domestic species?

Answer 53

chorion of fetal membranes attach to endometrium, do not implant

Question 54

what do chorionic villi do?

Answer 54

interdigitate with maternal endometrium to form placenta

Question 55

the trophoblast of the conceptus differentiates to form the chorion, which later fuses with the allantois to form the ____________________

Answer 55

chorioallantois

Question 56

what does it mean for a placenta to be epitheliochorial?

Answer 56

maternal endometrial epithelium intact and in contact with chorionic villi

Question 57

what does it mean for a placenta to be endotheliochorial?

Answer 57

maternal endometrial epithelium is completely eroded to the maternal capillaries are in direct contact with the chorionic villi

Question 58

what does it mean for a placenta to be hemochorial?

Answer 58

maternal endothelium is eroded and the chorionic villi are bathed directly in maternal pools of blood

Question 59

who has binucleate giant cells in their placenta?

Answer 59

ruminants

Question 60

what type of placenta do ruminants have?

Answer 60

synepitheliochorial

Question 61

what produces pregnancy associated glycoproteins in ruminants?

Answer 61

binucleate giant cells

Question 62

what is the "progesterone block"?

Answer 62

inhibits myometrial contractions

Question 63

which species require corpus luteum progesterone production for the entire gestational period (CL-dependent species)?

Answer 63

cow sow doe bitch llama/alpaca

Question 64

what are some hormones of placental origin found in some species, but not others?

Answer 64

placental lactogen relaxin

Question 65

what triggers the onset of parturition?

Answer 65

fetus: ACTH released from fetal anterior pituitary

Question 66

what does ACTH from the fetal anterior pituitary cause?

Answer 66

cortisol release from fetal adrenal gland

Question 67

what lyses the corpus luteum of pregnancy?

Answer 67

PGF2alpha

Question 68

what is stage 1 of parturition?

Answer 68

initiation of myometrial contractions positioning of fetus for birth ends with dilation of cervix

Question 69

what is stage 2 of parturition?

Answer 69

expulsion of fetus from birth canal hallmark is abdominal press presence

Question 70

what is stage 3 of parturition?

Answer 70

expulsion of placenta

Question 71

what will happen to a primary follicle?

Answer 71

develop into secondary follicle or degenerate

Question 72

what is the graffian follicle?

Answer 72

when tertiary follicle becomes dominant follicle

Question 73

what is the theca interna?

Answer 73

loose connective tissue surrounding the follicle

Question 74

what protrudes into the pituitary stalk region known as the median eminence?

Answer 74

axons of neurons in the tonic and surge centers

Question 75

what happens in proestrus?

Answer 75

formation of ovulatory follicles estrogen secretion

Question 76

what does the preovulatory LH surge coincide closely with?

Answer 76

onset of behavioral estrus due to high estrogen/low progesterone levels

Question 77

how long after the preovulatory LH surge does ovulation occur in most species?

Answer 77

24-36 hours

Question 78

what are the four stages of spermatogenesis (names of sperm precursors) that occur in the testes?

Answer 78

spermatogonia spermatocytes spermatids spermatozoa

Question 79

how does pregnancy recognition work?

Answer 79

interferes with action of PGF2alpha on corpus luteum lysis

Question 80

what are the functions of progesterone?

Answer 80

stimulates secretion by endometrial glands inhibits myometrial contractions stimulates closure of cervix helps maintain immunologically favored environment of fetus associated with changes in blood flow and metabolism