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Flashcards in Porcine reproduction Deck (72)
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1
Q

Describe the life cycle of the porcine ovary (steps)

A
  1. primordial follicle
  2. primary follicle
  3. secondary follicle
  4. early antral follicle
  5. atretic follicle
  6. graafian follicle
  7. ovulation
  8. early corpus luteum
  9. mature corpus luteum
  10. corpus albicans
2
Q

Describe the primordial follicle, stage of oocyte and influence

A

it has a central located oocyte and single layer of granulosa cells

  • basement lamina
  • dictyate oocyte
  • granulosa cells

oocyte is in arrested meiotic prophase

Growth independent on gonadotropin

3
Q

Describe the primary follicle, stage of oocyte and influence

A

follicle growth, proliferation of granulsa cells, zona pellusicda formation, theca cell differentiation

fully grown oocyte

growth is gonadotropin independent

4
Q

Describe the secondary follicle, stage of oocyte and hormonal influence

A

follicle growt, increased number of granulosa cell layers

fully grow oocyte

dependent upon gonadotropins to grow

5
Q

Describe early tertiary (antral) follicle

state of oocyte

Hormone relations

A

formation of the antrum, increased number of granulosa cells

fully grown oocyte

gonadotropin dependent growth, secretion of steroids by granulosa and theca cells

6
Q

Which follicles have a Gonadotropin dependent growth?

A

Secondary follicle, early tertiary follicle

7
Q

Secretions by theca and granulosa cells

A

Theca cells: androstendion

Granulosa cells: estradiol

8
Q

Describe the structures present in a pre-ovulatory follicle

stage of the oocyte

A

Blood vessles inbetween the theca cells

basement membrane, granulosa cells

‘antrum with follicular fluid and

oocyte at metaphase II stage

9
Q

What is the cause for the increasing progesterone level judt before the ovulation?

A

Just before the ovulation, the wall of the follicle has an increasing number of lutein cells growing - glutein patches

they produce progesterone

10
Q

What is special about the pre-ovulatroy follicle? structurally

A

It has an antrum with follicular fluid

11
Q

What hormones are found in the follicular fluid

A

estradiol in the follicular phase

progesterone at ovulation

12
Q

Describe the Peri-ovulatory/luteinizing follicle

A

theca-luteal cells

increase vascularization

granulosa-luteal cells

disruption og basement membrane –> oocyte ovulating

13
Q

What causes the oocyte to leave the follicle?

A

The increaseing pressure inside the follicle due to the increasing FF, the basement membrane ruptures and the oocyte is pushed out

14
Q

Define follicle rupture

A

“flow out”

of a mature follicle and discharge of an oocyte into the oviduct

15
Q

Why is the ovulation a inflammation like process?

A

There is structural changes

  • the follicular wall will change
  • there will be a dissolutionof the CT of tunica albuginea and theca interna

Canges in vascularization

  • marked hyperemia and edema
  • increased ovarian and follicular blood flow
  • increased vascular permeability

proteolytic enzymes

  • plasmin activating system
  • collagenase

influence of prostaglandin

16
Q

What is the cumulus-oocyte complex

A

the ovulated oocyte protected by a cloud of granulosa cells

17
Q

What are the main elements of corpus luteum development

  • preovulatory
  • periovulatory
  • post-ovulatory
A

preovulatory

  • vascular elements
  • granulosa cells
  • thea cells

periovulatory

  • hyperaemia
  • enlargement
  • lutein patches producing progesteron

post ovulatory

  • increasing vascularization
  • break of the theca-granulosa barier
  • invasion of vascular elements into the luteal parenchyma
  • dispersion of theca cells throughout the corpus luteum
18
Q

What celltypes are present in the corpus luteum?

A

immune system cells

fibrocytes

large and small luteal cells

vascular cells

19
Q

Define luteolysis

A

the process whereby the corpus luteum degenerates near the end of the nonfertile estrous cycle

20
Q

What are the mechanisms regulating the lifespan of CL?

A

reduction of LH pulse of CL

increased estrogen production

influence of PGF2a

21
Q

Difference of the secretion of LH in the luteal and follicular phase

A

follicular: LH is secreted in smaller concentration but in higher amplitude

luteal phase: LH is secreted in higher concentration but at lower amplitude

22
Q

Length of the pig cycle

A

21 days

23
Q

Define recruitment

A

the process wherin the follicle departs from the resting pool to begin a pattern of grwoth and development

24
Q

Define selection

A

final winnowing of maturing follicular cohort by atresia down to a size equal to the species characteristic ovulatory quota

25
Q

How many days does it take for the follicule to get to the preantral phase?

A

90 days

26
Q

how many days does it take for the early antral phase to get to the antral phase?

A

14 days

27
Q

Does pigs have 1 or 2 waves of LH?

A

1

28
Q

During which phase does the recruitment occur?

A

during the luteal phase

29
Q

During which phase does the selection occur?

A

Follicular phase

30
Q

What is the dual function of the follicle?

A

steroidgenesis

gametogenesis

31
Q

What is the FF?

A

serum transudate modified by follicular metabolic activities

32
Q

Functions of the FF

A
  • regulation of granulosa cell function, initiation of folliuclar growth and steroidgenesis
  • oocyte maturation and ovulation
  • preparation of the follicle for the formation of subsequent corpus luteum
  • regulation of the follicular cycle (inhibitory and stimulatory factors
33
Q

Meiotic maturation

A

the progression from the dictyate stage to metaphase II of meiosis

34
Q

Characterization of meiotic mautration

A

dissolution of oocyte’s nuclear membrane

condensation of chromatin

separation of homologous chromosomes

emission of the first polar body

arrest of meiosis with chromosome aligned ont he metaphase II spindle

35
Q

describe the progression from primoridal germ cells to oocte at ovulation

A

In the fetus

  • initiation of meiosis
  • meiotic arrest

in the post partum adult

  • growt of the follicle
  • respumption of meiosis at full growth
    • metaphase II
  • meitoc arrest
36
Q

How long will all the recruited cells keep growing?

A

the primoridal follicles that are recruited from the resting pool willgrow for 3 months until it reaches the preantral stage, and then during the estrous cycle they will grom from small antral to preovulatory follicles

37
Q

What is the boar:sow ratio?

A

1:25

38
Q

minimum age of breeding, boar

A

7.5 months

39
Q

Gloved hand collection

A

easy, observation of penis and seminal fuid

first ejaculation should be discarded

filter out the seminal plasma gel

40
Q

Functions of the oviduct

A

Pick up of oocyte

transport of both sperm and oocytes

sperm reservoir

sperma and oocyte development: capacitation

fertilization

early embryonic development

41
Q

Histiroarchitecture of the oviduct

A

infundibulum

ampulla

isthmus

42
Q

Uterotubal junction

A

Where the sperm cells are stored

43
Q

ampuleric istmic junction

A

the exact site of fertilization

44
Q

The oviduct changes its milieu during the different part of th cycle, which are the factors being altered?

A

pH

osmotic pressure

nutrients

specific secretory products

signal molecules

45
Q

Describe the sperm transport

A
  1. rapid passage through the uterus
  2. clonization of a sperm reservoir in the caudal isthmus - UTJ
  3. slow release toward the site of fertilization - AIJ
46
Q

what is the ration of sperm to oocyte in the ampullary part of the oviduct?

A

relatively equal porpotion to prevent polyspermy

47
Q

What are the mechanism of regulation to prevent the polyspermy?

A

sperm gradient

ovarian control of sperm release from the functional sperm reservoir to ensure a relevant sperm/oocyte ratio

48
Q

What is the sperm gradient in the uterus as opposed to the AIJ?

A

billions to couple 100

49
Q

How are sperm cells kept at the reservoir?

A

they get into a temporary arrest becuase of

  • narrowed lumen,, increased oedema of the mucosa and a viscous mucus
  • lower temperature
  • local enzymatic and ionic milieu
  • selective binding of spermatoxoa to the epithelium
  • dramatically reduced sperm motility
  • delayed capacitation
50
Q

What causes the sperm cells to move out from the reservir (peri-ovulatory progression of spermatozoa from the functional reservoir)

  • ovarian signals (progesterone)
  • opening of the lumen, decreased oedema
  • capacitation, acrosomal reaction
  • dissolution of the hyaluronicacid rich mucus
  • hyperactive sperm motility - only in isthmic section
  • directed oviductal contraction - peristalsis
A
51
Q

Describe the oocyte pick-up and transport

A

the oocytes are ovulated at the metaphase stage II

oocytes are picked up by the cilia-covered fimbria and guided through the indundibulum intot he ampulla

oocytes in their cumulus aggregate within a so-called egg or cumulus plug - the cumulus fights off the ciliary cells protecting the oocyte allowing it to move forward untouched

oviductal contractions will also move it toward the ampulla

52
Q

ovum transport and fertilization

A

rapid transport - 30 min . thorugh the infundibulum and to the ampulla to the AIJ

cumulus expansion - dissolution of the remaining cumulus investment

at the same time the sperm are let out of the reservoir and transported/swims to AIJ

53
Q

Fertilization - Explain in general steps

A

Oocyte MII + spacitated spermatozoa attaches

(ZP-binding, acrosome reaction, oocyte activation MII–>AII)

penetration

zona hardening and pronucleus formation

fusion of x and c pronucleus

zygote

54
Q

early embryonic development within the oviduct

A
  1. development form zygote to IV cell embryo
    • zygote after 8h
    • cleavage starts one day later
    • IV after 26-32h
  2. IV-cell embryo enters the uterus after 50-56h

at this time the concentration of progesterone ahs gone up and the lumen os the isthmic section is increasing so that the embry is able to enter the uterus

55
Q

Factors influencing the fertilization within the oviduct

A

sperm aging - premature inseminaiton

oocyte aging - belated insemination

infulence of endogenous hormone dysregulation and of exogenous hormones - superovulation

56
Q

sperm - steps during fertilization

A
  • the sperm penetrates the cumulus
  • acrosomal sperm activation
  • contact with ZP (hardening) - loosing the tail
  • penetration into the perivitelline space
  • completion of the second meitoic division
    • polar body is extruded
    • decondensation of sperm head
  • pronucleus formation
    • extrusion of 2nd polar body
  • pronuclus migrate to oocyte center
    • dispersion of nuclear enveloped
  • prophase of 1st mitosis division
57
Q

Describe the zygote stages in the

  • oviduct
  • uterus
A

Oviduct: zygot –> IV-cell

uterus: VIII-cell –> blastocyst (32)

58
Q

Blastocyst formation

A

development of tight intracelluar junctions of the morula during compaction is folloed by th accumulation of fluid with the central cavity froming a blastocoele

or explained differently

after the morula stage there will be growing and dividing blastocysts that are slowly differing from eachoter - differ into two types of cells in the expanded blastocyst whilst a cavity is formed along side filled with fluid

59
Q

How is the position of the cells in the growing blastocyst relevant?

A

with the expansion of the blastocoele (fluidcavity) it will position cells on the inside or outside of the vesicle where they differentiate into trophoblasts (outside) or embryobladt (inside)

60
Q

Zonal hatching

A

The growing blastocyst is getting too big for the ZP - it takes 6 days for the blastocyst to outgrow the ZP

it is a combination of physical and enzymatic process

61
Q

Why is it important to know when the zonal hatching occurs?

A

In embro collection. it is impossible to find the embryo after it has hatched

62
Q

Intrauterine migration

A

after th hatching, and the loss of XP the emrby can now attch to the maternal uterine epithelium

63
Q

Intrauterine spacing

A

it is important with equidistant spacing to ensure embryonic survival. the embryos must be spread out to as cover most of the tissue of the uterus so that less estrogen can be produced

64
Q

For how many days does the embry migrate and space?

A

until day 12

65
Q

Explain the most important steps of early pregnancy

A

Fertilization

  • sperm attachment
  • sperm penetration
  • pronucleus formaiton

cleavage

  • 2- cell embry to morula

ealry embryonic development

  • blastocyst formation
  • zona hatching
  • intrauterine migration and spacing

implantation

  • conceptur expansion
  • implantation
66
Q

Time events in early embryonic development

blastocyst formation

blastocyst elongation

initial placentation

birth

A

Blastocyst formation

  • blastocyst: 5-6
  • hatching: >6

blastocyst elongation

  • 11-15days

initial placentation

  • 13d

birth

  • 112-115 d
67
Q

At the late blastocystic stage the blastocyst will divide into ICM and trophectoderm cells - what will these further develop into?

A

Trophectoderm cells: placenta

inncer cell mass: fetus

68
Q

Gastrulation

A

establishing the further development

3 cell layers of ICM

69
Q

3 cell layers of ICM

A

Ectoderma, mesoderma, endoderma

70
Q

further differentiation of ectoderm

A

skin, hair, mammary gland, nerovous system

71
Q

further differentiation of mesoderm

A

heart, blood vessel, kidneys, bones, musces, reproductiveorgans, CT, adipose tissue

72
Q

further differentiation of endoderm

A

liver, pancreas, epithel layer of GI organs, resp orgnas