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 

major functions:

similar to growth hormone, promote growth of fetus

stimulates mammary gland of the dam

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 ; these cells produce progesterone and estrogen

endoderm

embryonic germ layer that the ICM gives rise to including digestive system, endocrine system, and lungs

mesoderm

embryonic germ layer that the ICM gives rise to including muscle, skeleton, cardiovascular, repro system

ectoderm

embryonic germ layer that the ICM gives rise to including nervous system, skin, hair

fetal growth stage

period of development from time the conceptus is classified as a fetus until parturition

cleavage stage

stage of conceptus development from fertilization until hatching from ZP

differentiation stage

stage of conceptus development from time of blastocyst hatching until embryo differentiates into a fetus

growth stage

stage of conceptus development from time conceptus is classified as a fetus until parturition

cleavage divisions

s series of mitotic divisions ; cells divide into 2, 4, 8 and 16 daughter cells ; each product (daughter cell) is called a blastomere

totipotent

ability of a blastomere to give rise to complete fully formed individual ; identical twins are derived from a single embryo that splits into 2 this is possible because the cells are….

mass

all cleavages within ZP create more cells but not more….

morula

when a solid ball of cells is formed and individual blastomeres can no longer be counted accurately the early embryo is…

gap junctions

during the morula stage, inner cells develop…..that allow for communication

tight junctions

dur4ing morula stage, outer cells develop…..which are cell-to-cell adhesions

blastocoele

as inner cells and outer cells separate fluid begins to accumulate in a cavity called the…

blastocyst

when blastocoele fluid becomes recognizable the embryo is called a…..

ICM

during blastocyst phase, inner cells develop the

trophoblast

during blastocyst phase, the outer cells develop the….which will eventually form the chorion (fetal component of placenta)

1. development within confines of ZP

2. hatching of blastocyst

3. maternal recognition of pregnancy

4. formation of extraembryonic membranes

4 stepes before embryo attaches to uterus

filamentous / threadlike

in pig, sheep, and cow blastocysts become….

spherical

in horse blastocysts remain….

long preattachment period

preattachment period that most domestic animals have ; several weeks ; extraembryonic membranes form before attachment

short-preattachment period

preattachment period primates have ; implants very soon after entering uterus ; extraembryonic membranes form after attachment

yolk-sac

originates from fetal midgut ; nutrient supply for early embryo ; absorbs uterine secretions from endometrium to stimulate early embryonic development

amnion

innermost membrane directly surrounding the fetus ; protects from injury and provides lubrication for parturition ; prevents lung collapse and opens digestive tracts

allantois

originates from gut and forms umbilicus ; supports blood vessels ; reservoir of nutrients and waste

chorion

outermost membrane in direct contact with uterine tissue ; becomes vascularized by allantoic vessels ; site of hormone production, nutrient and gas exchange

allantochorion

product of fusion between allantoic and chorionic membranes

cotyledon

placental unit of trophoblastic origin consisting of abundant blood vessels and connective tissue from fetal chorion

caruncle

placental unit of the uterus that protrudes from maternal endometrial surface

placentome

a caruncle and cotyledon together forming the functional unit of the placenta.

cow and ewe

which 2 species have an epitheliochorial and syndesmochorial type of placenta?

2-6 hours

how long is stag e 1 parturition in cattle

30-60 min

how long is stage II parturition in cow?

6-12 hours

how long is stage III parturition in cattle

retained placenta

common in cattle and horses ; chance of this increases during dystocia

dystocia

term for a difficult birth ; major cause of fetal death

causes:

abnormal presentation

excess size fetus

multiple births

relative dystocia

normal sized calf and small birth canal

absolute dystocia

abnormally large calf and normal sized birth canal

equine dystocia

more serious than other species due to intensity of contractions

PGF2a and corticoids

hormones used to induce parturition

puerperium

period between parturition and return to normal cycling state of uterus and ovaries ; initiated immediately following parturition along with lactation

uterine involution

process that uterus undergoes that takes place during puerperium where the uterus is repaired and shrinks

1. myometrial contractions

2. endometrial repair

3. resumption of ovarian function

4. elimination of bacterial contamination of reproductive tract

4 major events of puerperium

lochia

bloody discharge containing remnants of fetal placenta and endometrial tissue which is expelled from the vulva after parturition

true

t or f: uterine involution and resumption of ovarian activity are typically not achieved at the same time

leukocytes

high estradiol causes increased…..which helps with contractions and recruits an immune response to get postpartum bacteria out along with lochia