Repro phys 4th exam

male and female pronucleus fuse

an ootid becomes a zygote when…

luteolysis must be prevented

progesterone must be maintained

during maternal recognition of pregnancy what must be prevented? what must be maintained?

bovine interferon tau

bovine pregnancy recognition signals

ovine interferon tau

sheep pregnancy recognition signal

estradiol

sow pregnancy recognition signal

embryo migration

mare pregnancy recognition signal

trophoblast

before the fetal component of the placenta is classified as a chorion it is first a

uterine endometrium

maternal component of placenta

diffuse

placenta shape that is a uniform distribution of chorionic villi ; ex - sow and mare

cotyledonary

placenta shape where placentomes are the point of maternal/fetal contact - cow and ewe

zonary

placenta shape where there is a zone or a band of chorionic villi attached to the endometrium - bitch, queen

1. epitheliochorial

2. syndesmochorial

3. endotheliochorial

4. hemochorial

list placental types from least invasive to most invasive in order.

eCG (mares)

progesterone

placental lactogen

estrogen

relaxin

important hormones produced by placenta.

eCG

hormone strictly in mares ; produced by endometrial cups of the placenta ; stimulates maintenance of the CL and promotes development of the accessory CL

progesterone block

inhibits myometrial contractions

not necessary 

in ewe, mare, and humans the CL is…..for entire gestation

a must

in sow the CL is…..for entire gestation

needed for most of pregnancy

in cow the CL is…..

placental lactogen

found in ruminants ; produced by binucleate giant cells ; may be involved in heavier v lighter calves because sire affects degree to which this is produced 

1. promote fetal growth

2. stimulate mammary gland

2 main functions of placental lactogen

estrogen

the peak of…. during the last part of gestation signals early preparturient period

relaxin

hormone that is produced by the placenta and functions to soften connective tissue and allow muscles and ligaments to stretch in preparation for parturition

cow

which species does not produce relaxin from the placenta

adrenal corticotropin (ACTH)

a stress hormone released from the fetal anterior pituitary when they begin to run out of room in the placenta beginning the onset a parturition

fetal cortisol

stimulated by ACTH ; initiates a cascade of events that cause changes in the endocrine condition of the dam which is responsible for initiating parturition

1. removal of progesterone block enabling myometrial contraction

2. increased reproductive tract secretions

endocrine changes in the dam due to fetal stress cause what 2 major events to occur

1. myometrial contraction (progesterone block removal)

2. expulsion of fetus

3. expulsion of fetal membrans

3 stages of parturition

E2 and PGF2a

which hormones increase to activate myometrium and contractions

pressure-sensitive neurons

neurons in the cervix that causes a neural response and oxytocin release

stage 2 of parturtion

fetal head and front legs put pressure on fetal membranes, rupturing them ; loss of amniotic fluid lubricates birth canal ; as fetus enters birth canal hypoxia occurs promoting movement of the fetus causing more contractions

presentation, position, posture of calf

presentation - anterior

position - dorsal side up

posture - front legs offset, bottom of hooves facing down, nose between front legs

twins

in sheep what is present if a front and rear leg appear together

presentation, position of swine

presentation - anterior or posterior

position - dorsal or ventral

litter bearing species

presentation, position, posture of foals

presentation - anterior

position - dorsal side up

posture - front legs first bottom hooves facing down, nose between front legs

horses

name the species where it is crucial for the young to be born within 30 mins of beginning stage 2 due to crushing of the umbilical cord

microcotyledons

small placental structures seen in mares that are chronic villi

endometrial cups

seen in placenta of mare ; discrete areas of both trophoblast and endometrial origin ; produce eCG

cow

which species placentomes form a convex structure in cotyledonary placenta

ewes

which species placentomes form a concave structure in the cotyldonary placenta

epitheliochorial

placenta type that is the least invasive ; has all 6 layers present between maternal and fetal blood

syndesmochorial

placenta type that is a subgroup of epitheliochorial placenta ; endometrial epithelium erodes and then regrows causing intermittent exposure of maternal capillaries to chorionic epithelium

endotheliochorial

placenta type that is the complete erosion of endometrial epithelium and underlying interstitium

hemochorial

placenta type that is the most invasive ; chorionic epithelium is in direct contact with maternal vasculate ; possesses 3 layers

binucleate giant cells

cells that are unique to ruminants ; invade endometrial epithelium and transfer complex molecules from fetal to maternal placenta