Physiology Ii - Female Reproduction

Front 1

What makes the canine estrus cycle different from any other species?

Back 1

1. follicle produces progesterone just prior to ovulation 2. ovulated oocyte must mature before fertilization 3. no pregnancy recognition needed, both pregnant and non-pregnant ******* will go through the same diestrus period

Front 2

How long are estrus and diestrus in dog?

Back 2

both 7-10 days

Front 3

estrogen levels highest and progesterone lowest during ?

Back 3

estrogen levels highest and progesterone lowest during ESTRUS

Front 4

follicular phase consists of ?

Back 4

proestrus and estrus

Front 5

ovarian artery provides ovary with

Back 5

blood

Front 6

At sexual maturity there are 200,000 primary oocytes (immature eggs) in woman's ovary, what stage of meiosis are these primary oocytes arrested in?
Haploid or diploid?

Back 6

Diploid, arrested in prophase I of meiosis

Front 7

prostaglandin (for ovary) is produced in?

how does it get to artery?

Back 7

uterine mucosal lining

from uterine vein -> ovarian artery (counter-current system) -> ovary and luteal tissues

Front 8

What does estrogen come from?

Back 8

Ovary

Front 9

Estrogen triggers release of?

Back 9

* triggers release of GnRH from ovary and LH from anterior pituitary

Front 10

2 hormones that stimulate release of LH?

Back 10

GnRH and estrogen from ovary

Front 11

Production of prost. incr. during ?

Back 11

luteal phase

Front 12

are any new oocytes formed after birth?

Back 12

NO

Front 13

lifespan of mature oocytes (female)?

Back 13

brief, ~24 hrs.

Front 14

when is next estrus postponed?

Back 14

if mating is successful

to provide embyro time to develop

Front 15

Estrous Cycle Summary

The estrous cycle involves periodic
ovarian changes with 2 major phases:

Back 15

1. FOLLICULAR PHASE (ca 1/3 of cycle)
2. LUTEAL PHASE (ca 2/3 of cycle)

Front 16

What stimulates Ant.Pit. gland to release (FSH & LH)?

Back 16

Hypothalamic (GnRH)

Front 17

What stim. release of gonadal testosterone?

Back 17

pituitary (FSH & LH)

Front 18

HYPOTHALMUS contains what two centers:?

Back 18

Hypothalamus contains:
Tonic center
Surge center (only in female)

Front 19

Fetal testosterone inhibits ______ - males only have _______?

Back 19

Fetal testosterone inhibits surge center; males only have tonic center

Front 20

Tonic center of hypothalmus Produces?

Back 20

Produces GnRH (gonadotropin releasing hormone) → enters the portal system and stimulates anterior pituitary gland to produce and release the gonadotropins

Front 21

What are the gonadotropins?

Back 21

FSH - follicle stimulating hormone
LH - luteinizing hormone

Front 22

What type of breeders coordinate time of birth with favorable climatic conditions, and its main influences are photoperiod and ambient temperature? Examples?

Hint: these animals that have one or more estrous cycles
during certain periods of year

Back 22

seasonal breeders

animals that have one or more estrous cycles
during certain periods of year (not continuous)

examples: sheep, goat (add more)

Front 23

What type of breeders breed during the spring/summer, the pineal gland responds to increased light which decreases melatonin and increases GnRH release?

Back 23

long day breeders (horses, cats)

Front 24

What are animals called that breed during AUTUMN/early WINTER?,

Back 24

short day breeders (goats, sheep, deer)

Front 25

In short day breeders (sheep, etc), pineal gland responds to decreasing light, by?

Back 25

decreasing light --> increased opioids release from pineal & incr. GnRH release which stimulates spermatogenesis in male and female cycles?

Front 26

What center shows spontaneous basal GnRH secretion in pulses of 1.5-2 hours, stimulates release of gonadotrophins FSH and LH from anterior pituitary gland?

Back 26

Tonic Center

Front 27

What produces low basal GnRH pulses until estrogen reaches critical threshold, responds with massive release of GnRH= surge?

Back 27

Surge Center

Front 28

What is it called when progesterone lowers pulse frequency / amplitude of both centers (tonic and surge), and inhibits GnRH surge?

Back 28

Negative feedback control

Front 29

When reaching puberty, females enter a period of cyclical reproductive activity characterized by series of predictable events, involving the ovaries, uterus, and behavior, what is this called?

Back 29

Estrous cycles

Front 30

What is the process of acquiring reproductive competence (being able to support pregnancy)?

When does formation of graafian follicles begin?

Back 30

puberty in females

puberty, b/c it is hormone dependent
(gr.follicle formation begins at puberty when tonic levels of LH and FSH begin to rise and fall with each oestrous cycle)

Front 31

What is the onset of puberty in females influenced by?

Back 31

threshold body weight (fat tissue is powerful endocrine producer and main determinant in onset of puberty);
also genetic factors e.g. age (this is main factor in males), external factors or social factors

Front 32

What are polyestrus species?

Back 32

cow, pig, human, have continuous cycles throughout the year

Front 33

What are seasonal polyestrus species?

Back 33

horse, cat, sheep, wild ruminants, continuous cycles during a certain season only, followed by silent period

Front 34

What are monoestrous species?

Back 34

dog, one cycle occurs, followed by silent period

Front 35

What is a period without estrus cycles, caused by pregnancy, photoperiod, lactation, "stress"?

Back 35

anestrus

Front 36

What is luteolysis?

What causes luteolysis ?

Back 36

Regression of CL

PGF2 alpha

Front 37

What phase of the estrous cycle consists of and proestrus and estrus, is dominated by folliculogenesis with estrogen production, estrogen leads to sexual receptivity, and peak estrogen levels initiate ovulation via GnRH/LH surge?

Back 37

follicular phase

Front 38

What phase of the estrous cycle consists of Metestrus and Diestrus, conversion of ovulated follicle into corpus luteum with production of progesterone, progesterone prepares endometrium (inner membrane of the mammalian uterus) for pregnancy, ends with regression of corpus luteum?

Back 38

luteal phase

Front 39

What is the purpose of the estrous cycle?

Back 39

release ova ready to be fertilized, coordinate time of ovulation with copulation, prepare uterus for attachment, switch over to pregnancy state or induce new cycle

Front 40

During what phase for the hypothalamic tonic and surge center release basal pulses of GnRH, which stimulate corresponding FSH and LH?

Back 40

proestrus

Front 41

What is it called in proestrus, when FSH stimulated growth of a group of primary follicles to secondary and tertiary follicles?

Back 41

folliculogenesis

Front 42

In proestrus are FSH and LH both necessary to induce production of _____?

Back 42

estrogen

Front 43

In proestrus, what stimulates the theca cells to produce testosterone, which diffuses into granulosa cells?

Back 43

LH

Front 44

In proestrus, WHAT stimulates granulosa cells to convert testosterone to estrogen, which is secreted with fluid into blood and forms the antrum?

Back 44

FSH

Front 45

Upon gonadotropin stimulation, granulosa cells express more _____ receptors, and theca cells express more ____ receptors

Back 45

FSH, LH

Front 46

What is it called when cells become more sensitized to gonadotropins, leading to fast increase in estrogen concentration and proestrus behavior?

Back 46

up-regulation

Front 47

Exponential increase in estrogen induces what three events in sequence?

Back 47

1. estrus begins
2. inhibin release
3. LH surge

Front 48

What happens when estrus begins?

Back 48

standing heat, first sign of estrus is day 1 of cycle

Front 49

What happens during inhibin release?

Back 49

granulosa cells express LH receptors, producing inhibin, which inhibits FSH release, FSH decreases, leaving only 1 to few fully up-regulated follicles remaining active

Front 50

What happens during the LH surge?

Back 50

final increase in estrogen by fully up-regulated follicles, estrogen reaches critical threshold to activate surge center to release GnRH, leads to massive release of LH

Front 51

Luteinization begins when?

Back 51

Luteinization, beginning after rupture of the ovarian follicle in ovulation (A) and progressing through vascularization and hypertrophy of the maturing corpus luteum (B, C) ; it is followed by regression (D) to the corpus albicans (E) .
_______________
process taking place in luteal cells of graafian follicles that have matured and discharged their eggs: cells become hypertrophied and there is vascularization and lipid accumulation (latter in some species giving a yellow color), the follicles then become corpora lutea.

Front 52

The LH surge initiates lutenization of granulosa and theca cells,
both begin to produce progesterone instead of testosterone/estrogen/inhibin which leads to what?

Back 52

estrogen decreases rapidly, estrus behavior declines, progesterone increases slowly

Front 53

The LH surge blocks the ______ inhibiting factor.

Back 53

meiosis

Front 54

LH surge stimulates local production / release of histamine, proteolytic enzymes and prostaglandins E2 and F2a (vasodilation, proteolysis, transudation, myoid cell contraction) this leads to what?

Back 54

follicular swelling, pressure increase, breakdown of connective tissue, rupture of mature follicle with release of oocyte into abdominal cavity

Front 55

The most important event that the LH surge leads to is?

Back 55

spontaneous ovulation

Front 56

Some species do not ovulate spontaneously as part of cycle, but ovulation occurs only during or after copulation, coitus induces neuroendocrine reflex via vaginal and cervial receptors that leads to GnRH/LH surge, these kind of ovulators are?

Back 56

induced ovulators e.g. cat

Front 57

In induced ovulators, without copulation, there is no LH surge, no ovulation, what would happen?

Back 57

tertiary follicles become atrophic

Front 58

What species are induced ovulators?

Back 58

cats, camel, ferrets, minks, rabbits

Front 59

after ovulation, the follicular walls collapse & some bleeding occurs, antrum fills with blood clot called?

Back 59

corpus hemorrhagicum

Front 60

LH surge has induced lutenization in granulosa and theca cells; production of estrogen declines rapidly and progesterone increases slowly, what phase is this?

Back 60

luteal phase

Front 61

lack of estrogen abolishes estrus behavior, which means the end of estrus and the start of?

Back 61

metestrus

Front 62

Metestrus: corpus hemorrhagicum gradually luteinizes into the corpus luteum, which means?

Back 62

diestrus begins

Front 63

Diestrus: what does the corpus luteum contain?

Back 63

mature lutein cells

Front 64

What do LUTEIN cells produce?

Back 64

produce PROGESTERONE, which prepares the endometrium for potential pregnancy

Front 65

What do small lutein cells develop from?

Back 65

theca cells during early corpus luteum phase

Front 66

What do large lutein cells develop from?

Back 66

Granulosa cells, dominant during late corpus luteum phase

* following ovulation, granulosa cells divide rapidly forming CL

Front 67

Diestrus: the increasing progesterone levels suppress, but do not inhibit tonic and surge centers, which means?

Back 67

GnRH is released in low frequency/low amplitude pulses, followed by low pulses of FSH and LH

Front 68

What is necessary to keep corpus luteum viable?

Back 68

LH pulses

Front 69

FSH and LH pulses are sufficient to initiate folliculogenesis during diestrus called?

Back 69

follicular waves

Front 70

As long as progesterone is high (diestrus), the surge center cannot respond to elevated estrogen which means?

Back 70

no LH surge, no ovulation, atresia (passage closed!)

Front 71

Non-pregnant uterus starts to produce _______ towards the end of lutein phase.

Back 71

prostaglandin F2a

Front 72

PGF 2a reaches ipilateral ovary directly via a what?

Back 72

countercurrent blood system between uterine vein and ovarian artery

Front 73

PGF2a leads to apoptosis of luteal cells, the CL regresses and progesterone production stops, means?

Back 73

end of diestrus

Front 74

In what species is PGF2a produced by the CL, and the uterus is not needed to induce luteolysis?

Back 74

primates, probably carnivores

Front 75

When progesterone decrease lifts suppression on ?
which means?

Back 75

no more suppression on hypothalamic GnRH release,

Front 76

After progesterone decr and GnRH pulse increase again in frequency/amplitude, which increases FSH and LH, this means?

Back 76

new cycle can begin with proestrus

Front 77

In luteolysis, oxytocin is released from large luteal cells which initates?

(Where is oxytocin released from in dogs and primates?)

Back 77

In luteolysis, oxytocin released initiates PGF2a release from the endometrium

(however oxytocin is released from
posterior pituitary gland in primates, dogs)

Front 78

What species are oxytocin and PGF2a released in pulses?

Back 78

sheep

Front 79

*PGF2a* is produced by ___ when stimulated by ____?

acts on ____ to cause ____?

Back 79

Produced by uterus when stimulated by oxytocin, if NO implantation during follicular phase.
Acts on corpus luteum to cause luteolysis, forming corpus albicans and stopping production of progesterone. Action of PGF2α is dependent on number of receptors on corpus luteum membrane.

Front 80

PGF2a receptor numbers are high only in what cells?

Back 80

large lutein cells, during mid to late diestrus, PGF2a can induce luteolysis only during this time

Front 81

What can be used to induce luteolysis in all species?

Back 81

exogenous PGF2a

Front 82

What can inhibit PGF2a synthesis (in ruminants and pigs, but not in the mare)?

Back 82

acute/chronic endometritis, no luteolysis, persistant corpus luteum, persistant progesterone release, cycle locked in diestrus

Front 83

The PGF2α isoform 8-iso-PGF2α is significantly increased endometriosis, being a potential causative links in endometriosis-associated oxidative stress.[1

Back 83

The PGF2α isoform 8-iso-PGF2α is significantly increased endometriosis, being a potential causative links in endometriosis-associated oxidative stress.

Front 84

What phase is under estrogen: proliferation of endometrium, increasing thickness, hyperemia & swelling of vulva, endometrial and cervical glands secrete thin, string-forming mucous?

Back 84

proliferative phase

Front 85

What phase is under progesterone: growth of spiral arteries, increased blood supply, swelling of endometrium with increased secretory activity, accumulation of nutrients= ready for implantation/attachment?

Back 85

secretory phase

Front 86

What phase is it when blood vessels become vasospastic, necrosis of endometrium, desquamation, external bleeding= menstration?

Back 86

luteolytic phase

Front 87

What is the effect of estrogen on the uterus?

Back 87

proliferation of endometrium, mucus

Front 88

What is the effect of estrogen on the oviducts?

Back 88

proliferation of glandular tissue and ciliated cells; increase of cilia activity

Front 89

What is the effect of estrogen on the vulva/vagina?

Back 89

hyperemia, swelling, mucous

Front 90

What is the effect of estrogen on the mammary gland?

Back 90

deposition of fat, proliferation of stroma and duct system

Front 91

What is the effect of estrogen on the skeleton?

Back 91

increased osteoblastic activity and mineralization

Front 92

What is the effect of estrogen on metabolism?

Back 92

slight increase in protein synthesis, increased fat deposition / subcutaneous tissue

Front 93

What is the effect of estrogen on sexual behavior?

Back 93

initiates sexual receptiveness

Front 94

What is the effect of progesterone on the uterus?

Back 94

stimulates secretory activity of endometrial glands, decreases myometrial activity = progesterone block

one of roles of progesterone is to suppress contraction on uterine smooth muscle; eventually this is antagonized by rising estrogen lvl. @ end of gestation

Front 95

What is progesterone block?

Back 95

Suppression of contractility in uterine smooth muscle, which, often called the "progesterone block" on the myometrium. Toward the end of gestation, this myometrial-quieting effect is antagonized by rising levels of estrogens, thereby facilitating parturition.

Front 96

What is the effect of progesterone on mammary gland?

Back 96

development of mammary lobules and alveoli

Front 97

What contols the female reproductive center, including search for partner, courtship display, and sexual receptivity, and is sitmulated by high levels sof estrogen (during estrous phase)

Back 97

hypothalamic sex center

Front 98

In what species does sex center require priming by low levels of progesterone?

Back 98

cattle, pigs, sheep

Front 99

What are volatile / non-volatile chemicals produced by genitals, urinary tissue, or sebacous glands as 'olfactory communicators' which can influence the estrous cycle and mating behavior?

Back 99

phermones and estrous cycle

Front 100

What adaption found in female small ruminants induces cycling after males join herd?
Purpose of this?

Back 100

whitten effect (sin heep, goat)

synchronizes females and advance breeding season?

Front 101

Give 2 examples pheromone effects used in animal production systems

Back 101

Whitten effect:
Vandenbergh effect:

Front 102

Vandenbergh effect:

Back 102

when gilts (female pig) reach puberty earlier when exposed to a boar -> used to advance onset of puberty in this species

Front 103

for the establishment of pregnancy, maintenance of corpus luteum / progesterone is imperative, what must be avoided?

Back 103

luteolysis

Front 104

To avoid luteolysis (in most sp.) the conceptus has to interfere with what?

Back 104

endometrial PGF2a release

Front 105

What is the most important hormone to maintain pregnancy in all species?

Back 105

progesterone

Front 106

Where is progesterone produced?

Back 106

corpus luteum / corpora lutea

Front 107

At a later stage, what takes over progesterone production while the CL regresses?
Except in what species?

Back 107

placenta

not in pigs

Front 108

What are the functions of progesterone during pregnancy?

Back 108

1. support of endometrium - to provide environment condusive to survival of preggers (maintains secretory activity / perfusion of endometrium)
2. decreases uterus tone, increases cervix tone (progesterone block)
3. prepares mammary gland during late pregnancy

(also app. inhibit secretion of LH/FSH/GnRH -> prevent ovulation during pregnancy)

Front 109

What is the most important event initiating parturition, at end of pregnancy?

Back 109

an INCREASE in fetal CORTISOL production, leading to progesterone withdrawal

Front 110

What is cortisols target organ?

During parturition, cortisol stimulates 2 steroid hormone enzymes to convert what to what?

Back 110

What is cortisols target organ? PLACENTA


During parturition stim. -> progesterone to estrogen

Front 111

What does conversion of estrogen to progesterone cause?

Back 111

estrogen increases, progesterone decreases -> REMOVAL of the progesterone block
(remember this is occurring during parturition)

Front 112

Which of following is NOT a consequence of the estrogen increase after removal of the progesterone block (decr.progesterone)?
A. Number of gap junctions / myometrium increases -> single unit type smooth muscle (facilitates co-ordination of contractions)
B. Stimulates synthesis of contractile proteins (actomyosin)
C. Decreases number of oxytocin receptors
D. Stimulates mucous secretions, stimulates synthesis of placental prostaglandin F2a/ E2

Back 112

C. Not Decrease, there is INCREASE in oxytocin receptors
_______
Estrogen increase -> removal of block has what effects
1. Myometrium
- Number of gap junctions / myometrium increases -> single unit type smooth muscle (facilitates co-ordination of contractions)
- Induces an increase in oxytocin receptor numbers
- stimulates synthesis of contractile proteins (actomyosin)
--> prepares MYOMETRIUM (smooth muscle of uterus) to become CONTRACTILE
stimulates mucous secretions, stimulates synthesis of placental prostaglandin F2a/ E2

Front 113

What initiates regression of CL, leads to complete withdrawl of progesterone, assists in relaxing/dilating cervix, initiates intracellular contractions?

Back 113

prostaglandin F2a/ E2

Front 114

What is produced in some species by the CL, increases with PGF2a induced finala luteolysis ca. 10-14 hrs prior to birth, relaxes pelvic ligaments and muscles, separation of pelvic synthesis, facilitates expansion of birth canal?

Back 114

relaxin

Front 115

Are LH receptors on theca interna only? OR on granulosa cells also?

Back 115

Don't know, but think both..at first only on Theca internal but read that FSH stimulates formation of LH receptors on Gr. cells too
(like maybe ahead of big surge)

Front 116

After regression of the CL, do FSH and LH increase OR decr.?

Back 116

After luteolysis, FSH and LH secretion increases b/c of decrease in concentration of progesterone (made of by CL)

Front 117

What effect does progesterone have on FSH, LH release?

Back 117

decrease their release

Front 118

Which hormone converts Testosterone to Estrogen?

Back 118

neither, but FSH stimulates granulosa cells to do conversion :P

Front 119

T/F Many of the follicles that undergo growth and maturation with each cycle never ovulate.

Back 119

True

Front 120

In large species, Stage 1 parturition, the fetus aquires the correct 'diving position' for delivery, what is this positioning?

Back 120

anterior presentation

Front 121

Stage II parturition: fetal membranes, legs, head, or buttocks push against and finally enter the cerivx, pressure receptors are stimulated to initiate what?

Back 121

fergusson relflex / oxytocin release

Front 122

Receptors initiated rhythmic myometrial contractions, and simultaneously abdominal muscles contract causing?

Back 122

expulsion of the fetus

Front 123

What is stage III parturition?

Back 123

delivery of fetal membranes through sustained surges of PGF2a

Front 124

What is the period of uterus involution and regeneration, attachment points of fetala membranes slough off, new epithelium forms = healing of endometrium, myometrium retracts = size reduction?

Back 124

puerperium

Front 125

During last days before parturition, prolactin is released to do what?

Back 125

induce lactogenesis, induce maternal behavior

Front 126

What are paired cutaneous gland, which provides nutrients to the newborn and consists of a secretory system and a duct system?

Back 126

mammary gland

Front 127

What is the milk secreting unit of the mammary gland, lined with a single layer of epithelial cells and surrounded by dense capillary network and myoepithelial cells

Back 127

alveolus

Front 128

Describe the mammary gland at birth.

Back 128

gland present at birth, rudimentary duct system, parenchyma consistas of adipocytes and fibroblasts

Front 129

During puberty, there is exponential growth during first estrous cycles of the mammary gland, what are the functions of estrogen and progesterone?

Back 129

estrogen: lengthening and branching of ducts, progesterone: lobulo-alveolar development

Front 130

The mammary gland becomes functional only during gestation, stroma is replaces with alveolar tissue b/o long standing what?

Back 130

high estrogen/progesterone levels

Front 131

The actual production of milk is lactogenesis, and only begins a few days befor parturition, called the what?

Back 131

induction phase

Front 132

Lactogenesis has what 2 distinct phases?

Back 132

induction phase (before birth) and maintenance phase (p.p.)

Front 133

Induction phase is coordinated with parturition, meaning it is induced by the same hormonal changes, such as:

Back 133

withdrawl of progesterone prior to birth, increase in cortisol to induce prolactin receptors, increase in prolactin

Front 134

The increase in prolactin a few days prior to birth is stimulated by prolactin RH and suppression of prolactin IH which is what?

Back 134

dopamine

Front 135

What does C.E.P.R.O. stand for?

Back 135

The order of hormones in parturition: cortisol, estrogen, prostaglandin F2a, relaxin, oxytocin

Front 136

T/F Fat tissue is a powerful endocrine/hormone producer.

Back 136

True, e.g. leptin role in determining onset of puberty in female

Front 137

zona pellucida forms first in what follicle/phase?

why is the z.p. important?

Back 137

zona pellucida 1st appears on secondary follicle

it has sperm binding sites (w/o sperm can't bind to ovum)