repro full review

isthmus

uterine horn

fimbria

ampulla

oestrus

pregnancy

anoestrus

oocyte

zona pellucida

granulosa

thecal layer

this is a secondary lecture

leydig cell

order at which the developing sperm cell differentiate

• spermatogonia

• primary spermatocytes

• secondary spermatocytes

• spherical spermatids

• elongated spermatids

• spermatozoa

a- primary spermatocytes

b. spherical/secondary spermatocytes

c.

a. cotyledonary

b. diffuse, microcotyledonary

c. labyrinthine placenta

d. diffuse, folded

where is the foetal and maternal

a. foetal blood vessel

b. endometrium

c. chorion

d. foetal stroma

e. maternal blood vessel

f. maternal epithelium

areolae

endometrial cup

marginal haematoma

how is the cl formed

– The CL is formed from granulosa and theca cells of the ruptured follicle following ovulation. Theca and granulosa cells undergo a process termed "luteinization" to form large and small luteal cells. It is heavily vascularized.

function of the cl

• what does he secrete

• what does it convert

• secrete progesterone under the control o

• progesterone converts proliferative endometrium to secretory and inhibits smooth muscle contraction

luteolysis

the process by which the functional lifespano fht CL is terminated in the non fertile life cycle

lifespan of the cl in woman cow ewe sow mare

• 14

• 18

• 14

• 16

• 15

extracellular vesicles

• what are they part of

• where are they present

• what are there important functions

• what can embryonic cells able to uptake

• what might embryo derived extracellular vesicles do

• are part of communication between mother and embryo and carry bioactive molecules such as proteins,lipids, mrna and mirna

• small ev are present in the oviducatal and uterine fluid and have important functions during fertilisation and early embryonic dev

• embryonic cells are able to uptake oviductal and endometium derived small evs. conversely, embryo dervided ev may modulate oviductal and uterine function

maternal recognition of pregnancy

• signal from conceptus to mother

• first described in sheep

• takes various forms in different species

• biochemical signal sent by conceptus tissues to mother

• ensures maintenance of functional cl- cl continues to secrete progesterone instead of lysis and return oesrus.

pregnancy recognition in

• cow

• ewe

• sow

• mare

• woman

• queen

• bitch

what causes luteolysis in domestic ungulates

upregulation of uterine OTR

maternal recognition of pregnancy in the sow

• what hormone

• why

• oestrogen

• blastocyst expansion means that they transform from circular to tubular

• days 1/0-12 they become filamentous and reace 800-1000mm

• increases surface area contact with the

• mrp signal in sows is oestradiol

• secreted throughout- more secreted between days 11 and 15

impact of oestradiol in the sow

• what does it induce and how

induces an overall decrease in the secretion of pgf2a by

• retrograde transfer of pgf2a from the venous blood and lymph into the uterus

• decrease in pgf2a from the endometrium to circulation

• ability of uterine vein and artery to accumulate pgf2a

in addition, oestradiol promotes an increase in pge2 which acts as an luteotrophin to stimulate cl to secrete p4

requires 2 embryos per horn to provide sufficient signal

maternal recognition of pregnancy in the mare

• signal is unknown

• contunuous feto maternal dialogue

• luteolysin is thought to be pg2a

• endometrial otr is down regulated

• ot which interacts with otr comes from uterus rather than the cl

• unknown how down regulation is achieved

• embryo does secrete e2 from d10 but this is not the mrp signal

what happens when the embryo transport

• how many days to transvese the oviduct

• until what day does it move continuously through the lumen

• what are the ciritcal days

• takes 5.5-6 days to traverse the oviduct

• when it finally enters uterus it remains spherical in shape and moves continuously through the uteirne lumen until day 17 afterovuation to deliver the maternal recognition of pregnancy signal to the entire endometrium

• critical ays 10-14 days

placental gonadotrophins

hCG in human and some primates • eCG in the mare and other equids • Alpha chain - common to FSHA and LHA • Beta chain - unique for hCG and in common with LHB for eCG • NOT produced in other species • Bind to LH receptors - therefore main action is on the ovary to promote progesterone production • eCG: first from chorionic girdle – cells migrate into the endometrium – endometrial cups – lifespan 40 – 100/120 days – eCG related to cup presence

CG is a highly glycosylated form of LH with a very long half life (6 days) Luteotrophin is now available to ovulate or luteinise the follicles that develop in response to pituitary FSH waves

regulation of luteolysis during the oestrus cycle

• proestrus: E2 increases ESR1 and OXYR and PGR

• oestrus: no P4 so the PGR not active

• dioestrus: P4 is up, binds to PGR

  • -ve feedback on ESR1, low OXYR till day 10

• day 10-11 PGR downregulated by continuous P4- therefore block removed = day 11-12 ESR1 + and day 13-14 OXYR increase

upregulation of otr in the endometrium precedes lteolysisby PGF2a mean

• rising estrogen levels in the endometrium triggers the upregulation of OTRs

• then oxytocin binds to them

• this stimulates the endometrium to release PGF2a

• this travels to the ovary, more oxytocin

patterns of PGF2a, OXYR and P4 across the cycle when there

• no conceptus present

• conceptus present

when there is conceptus present

• pulsatile pgf2a release

• p4 level drop

• otr increase

• luteolysis occurs

when there is conceptus present

• little pgf2a secretion

• little otr expression

• p4 levels remain stable.

extracellular vesicle function

• embryonic development

• embryo migration

• cell apoptosis

• cell proliferation

• cell fusion

• immune regulation

• cell adhesion

• angiogenesis

MRP signal in ruminants when there is conceptus presnbent

• day 10- IFN tau

• binds to interferon r type i on the endometerial LE

• this stimulates IRF2 signalling

  • blocks ESR1 (through inhibiting signalling)

  • blocks OXYR

in pigs life of the corpora lutea are extended by a combination of increased secretion of estradiol and decreased secretion and redirection of PGF2a

migration of eCG

• first from chorionic girdle

• cells migrate into the endometrium to the endometrial cups

• lifespan 40-100/120 days

• eCG related to cup presence

what does luteotrophin do in response to pituitary FSH waves

ovulate or luteinise the follicles that develop

oestrus cycle in the bitch

• normal lifespan of CL is at least duration of normal pregnancy

• so no need for maternal recognition of rpgnancy

oestrus cycle in the queen

• queen is a reflex ovulator

• hence normally no luteal phase if not mated

• once formed, the corpus luteum normally last for 40-45 days

• however normal duration of prgnancy is 60 days

• so factors must be secreted in order to ensure that the lifespan of the CL is extended from 40-45 days to 60 days

  • maybe PRL

• also placenta provides progesterone in these latter weeks of pregnancy

transport of protein hormones from fetus to mother

• what are the fetally derived proteins and what are they produced by

• which type of placenta is transport easier in

• transport in mares and ruminant

• fetally derived proteins: placental gonadotrophins and placental lactogens both produced by the placental trophpblast cell in some species

• in species with a haemochorial placenta it is easier as trophoblast invade and line maternal blood vessels so easy transfer

• in mares the chorionic girdle cells which produce eCG detach from the epitheliochorial placenta and migrate into the endometrial stroma forming endometrial cups, and hte secretion of the cups are directly released into maternal tissue

• in ruminants placental lactogen migrate into the endometrium and hten the whole cell breaks down releasing its secretory grnaules close to the basement membrane and so enar the maternal capillaries

iron transfer

• some species have a haemophagous region where maternal blood cells are phagocytosed by fetal chorionic epithelium

  • the trophoblast cells express genes eg heem oxidase which opens up the ring structure of heme and release ferric iron creating biliverdin which is reduced to bilirubin

  • may form crystals of hematoidin

• other species produce special proteins with a high iron content

  • secreted by uterine glads and taken up y opposing allantochorion

  • may be arranged in areolae

  • eg uteroferrin reaches the blood and is cleared by the fetal liver whre the iron is extracted and utilised for hemoglobin synthesis

  • some uteroferrin is excreted with feta urine and reaches allantoic sac

  • in ares ron supplied by uteroferrin

  • it is secreted by endometrial glands and taken up by areolar trohobalst cells trough a pinocytotic or endocytotic process

hepcidin

• what is it

• a hormone involved in iron homeostasis

• acts of ferroportin

• controls the main inflows of iron into plasma eg duodenal enterocytes and macrophages and hepatocytes

• during pregnnacy it controls the placental transfer of iron from the maternal plasma to the fetal circulation

• when hepcidin concs are low within fetus, iron enters blood plasma at high rate

• when hepcidin concentration are high, iron is trapped in enterocytes, macrophages and hepatocytes thus not relased into plasma and not available

IgG

• need for innate immunity in early life

• more effcient with fewer placental layers

  • negligible transfer in 6 layer

• may be areas of placenta specialised for this

• eg in the bitch IgG taken up in the haemophagous zone is phagocytosed so does not reacht he fetal circulation intact

• but there are a subpopulation of maternal blood vessels in the labyrithine zone which are specialised for this

method of synchronisation of oestrus in ewes- what to think

• you need to think about the degree of syncronisation needed,

• the season

• and economic and market factors

the physiological method- ram

• what do rams stimulate through which cues

• how do you do it

• when is it/not effective

• what increases success

• the RAM effect

• rams stimulate gonadotrophin secretion and ovulation in anoestrus ewes through chemosensory cues

• it involves introduction of rams to ewes that have been previously isolated from the males for3-4 weeks

• only effective at certain times of the year (before the natural breeding season start, not females in deep anoestrus)

• majority of ewes ovuate within 6 days of being introduced to the ram

• priming with progesterone (intravaginal sponges or intra muscular injections) prior to the introduction of rams increases percentage of ewes showing oestrus behaviour

pharmacological method- progestagens

• how does it work

• what happens when withdrawn

• what must it last

• what must be given in anoestrus

• progestagens

• works in cyclic female by suppressing release of gonadotrophins

• on withdrawal of the progestagen, negative feedback is removed

• this leads to increasing amouonts of gonadotrophins and therefore oestradiol

• this increased E2 leads oestrus and ovulation

• must last the lenght of the luteal phase

• in anoestrus females the progestagen withdrawal is compemented by follicle stimulating treatments eg PMSG

• progestagens can be administered by different methods and routes

• eg sponges contains synthetic progestagens, FGA or MAP

pharmacological- prostaglandin

• what does it induce

• what does this then cause

• what does this lead to

• injection timing

• pgf2a can synchronise eostrus in cyclic ewes

  • induce luteal regression

• progesterone levels fall and negative feedback from progesterone is removed

  • level of gonadotrophin start to rise

• leads to increased follicular growth an e2 production which leads to oestrus within 2-3 days and ovulation shorty after

• CL is only responsive between days 5-14 of the cycle so need 2 injections 10-14 days apart for optimum synchronisation of the flock

problems with hte prostaglandin method

• variability of response

• need to inject cyclic animals

• induced oestrus leads to poor fertility, possibly due to limited exposure of the tract to progesterone

pharmacological- melatonin

• what kind of ewes given to

• to be successful when does it have to be given

• how long to elevate

• has been used to advance the onset of oestrus in seasonally anoestrus ewes

• to be successful melatonin treatment has to be initiated after a period of long day length

• need to elevate melatonin for -5 weeks for this method to be effective in bringing forward the season

how to induce early luteal regression in the cow

• what is given

• what oes this induce

• what does this lead to the start of

• when is the second injection needed

• pgf 2a

• from day 6-16 pgf2a will induce luteal regression

• leads to start of a new follicular phase which means that the animal will come into oestrus and ovulate shortly after

• for synchro of animals that are all at differnt stages, one injection is not enoguh

• a second injection is needed 11-13 days after because at that time all animals will have a functional corpora lutea

cow progestagens

• how long to treat

• what to combine

• effect in non cyclic ewes

• what to inject at the removal of PMSG

• for negative feedback

• mimic the luteal phase of the cycle

• need to treat for 10-12 dys

• to make sure that the natural CL has regressed by the time of progestagen withdrawal, it is customary combine progestagen treatment with a luteolytic factor

  • could use oestradiol at start or prostaglandin at end

  • oestriadiol preferred as it alo affects follicular dynamics hwich tend ot improve ertility

  • in non cyclic the progestagen sensitises the HPG axis which means that it can be used in cattle with inactive ovaires

  • injecting ith PMSG at removal of the progestgen stimulates follicular maturation and ovulation

  • Oestrus and ovulation after treatment with progestagens occur earlier and with a more precise timing than following prostaglandin injection alone

sheep inducing

• induce with dexamethasone

• PGF2a does not work well in sheep due to high placental progesterone

• PGF2a also not very successful for treating ring womb even if directly applied to the cervix

cow- induction of oestrus

• induce with dexamethasone followed by PGF2a

dog

• induction of parturition is rare

• oxytocin used to initiate uterine contraction

horses induction and what to avoid

• induce with low dose oxytocin

• avoid PGF2a as causes abdominal pain

• corticosteroids do not work

pigs

• induce with PGF2a and oxytocin

• corticosteroids do not shorten gestation in pigs

what is the gestattion length of a mare

330-340 days

what is the gestation length of a cow

270-280 days

gestation length of a ewe

147-150 dats

gestation length of a sow

115

gestation length of a bitch

63-65 days

gestation length of a guinea pig

60 days

luteolysis in gthe cow and ewe

• uterine pulsatile secretion of PGF2a

• diffuses from uterine vein to ovarian artery via the utero ovarian plexus in cows

• in sheep to utero ovarian vein to ovarian artery

• travels to CL

luteolysis in sows

• pusatile PGF2a release

• diffuses from uterus onto adjacent ovry luteal cells

luteolysis in the mare

• pulsatile PGF2a release from the uterus

• travel to ovary and destroy CL

luteolysis in the bitch

• relies on withdrawal of pituitary luteotrophic support (prolactin) in late diestrus

• dropping of prgesterone leads to the end of diestrus

• CL regression

what happens to fetal glucocorticoid levels during parturition

increase

effects of glucocorticoids in the fetus

• lungs

• kidney

• liver

• gut

• lungs- surfactant production, eta adrenergic receptors

• kidney- glomerular filtration rate, tubular na reabsorption

• liver- glycogen, gluconeogenic enzymes, igf gene expression, b adrenergic and gh receptor

• gut acid secretion,digestive enzyme, mucosal growth

in goats when does the corpus luteum secrete progesterone

at the end of pregnancy

what is the luteolytic hormone in goats

prostalgandin f2 alpha

onset of parturition in goats

• what must happen in order to start parturition

• what is it controlled by

• what is released

• fetus controls- must stop progesterone production by the CL to start parturition

• controlled by the fetal pituitary adrenal axis

• fetus becomes stressed, fetal ACTH is released and cortisol increases

• rise in fetal cortsol leads to an increase in oestrogen

• increase in oestrogen leads to an increase in PGF 2 alpha

• this increases luteoysis and decrease progesterone

• increased prostaglandin causes an increase in contraction and cervical softening

how does rise in fetal cortisol incease oestradiol

• leads to an increase in aromatizing enzymes

artificial induction of parturition

• dexamethasone

• potent synthetic corticosteroid

• works across speces

• takes 2-3 days to act

induction of parturition in pigs cows and sheep

• pgf 2 a

induction of parturition in human and horse

oxytocin

induction of parturition in cows

• when should it not be induced before

• risk of using dexamethasone

• what can be used to remove a mummified fetus

• should not be induced before day 269 of gestation

• can use dexamethasone

  • parturition in 48h

  • high incidence of retained placenta

• PGF2a

  • work near term

  • used to remove mummified fetus

induction of parturiition in sows

• how long does farrowing usually take

• farowing takes 2-8h

• PGF2a- parturition in 24-48h

• oxytocin- can be given if delay in expulsionn

• PGF in association with OXT 24h later

placenta

• what does it interact with and what does this form

• how does it connect to the embryo

• any intimate apposition of fusion of the fetal tissue to the maternal tissues for physiological exchange

• discarded at birth

• it will possess some maternal cells although these will be in the minority

• interacts with the maternal endometerium to establish the maternal fetal interface

• connets to the body of the embryo by vascular supply and latter the umbilical cord

functions of placenta

• exchange of nutrients and waste

• changes metabolism of mother

• protection from trauma and teratogens

• immunological protection

• hormone secretion

• influence development vital organs

non invasive implantation

epithelial integrity retained ( it may be breeched locally , transiently or in very late gestation)

invasive implantation and 2 types

conceptus breaks through the surface endometrium

interstitial- very deep invasion and surface epithelium restores

eccentric- stroma only partially invaded and conceptus continues to project into lumen

ewe implantation

• what does it require

• begins and ends at how many days

• type

• what happens just before implantation

• requires the endometrium to be receptive

• occurs beginning at 15 days and is complete by 28 days

• non invasive- epithelial integrity retained

• just before implantation- blastocyst elongation

what 4 placental membranes originate from the trophoectoderm

• yolk sac

• amnion

• chorion

• allantois

chorionic villus

• function

• what does it define

• how many per placenta

• what s it called in ewes and when

• what do trhey attach to and what does this form

• exchange of nutrients and gases

• chorionic villous distributed in different ways and defines the type of placenta

• ewe at distinct contact points called cotyledons

• 70-100 per placenta

• the cotyledons attach to uterine caruncles on the maternal side

• the term placentome refers to the combined caruncle and cotyledon

• the tissue between the codtyledons is more simple intercotyledonary chorion- simple trophoblast

• discoid / cotyledonary

the 6 layer intact- epitheliochorial

• fetal endothelium

• fetal connective tissue

• chorionic epithelium

• uterine epithelium

• maternal connective tissue

• maternal endothelium

umbilical cord

• connects the placenta to fetal circulation - ie provies lumen to channel the nutrients and gaes

• two arteries and 2 veins

• normal to have numerous plawues- foci of squamous metaplasia with keratin

maternal- fecal circulation

• what takes blood from the placenta to the foetus

• what takes blood from the foetus to the placenta

• what is thecapillary of the foetus very close to

vein takes blood from placenta to foetus

artery vice versa

exchange takes place at a placental level- lungs not needed

capillary of the foetus is very close to the cpaillary of the endometrium