W6 Maternal signs of pregnancy Flashcards
rMaternal signs of pregnancy importance
Conceptus unutallly signals its presence to the dam
Essential for maintenence of CL and hence pregnancy
Failure will result in preg loss
Must occur prior to luteolysis
Bovine and Ovine MRP
IFN-T release
Day 15-16 bovine
Day 13-14 ovine
Secreted by trophoblastic cells of blastoplast
Blocks oxytocin receptors, thereby oxytocin cant stimulate PGF2a synthesis
Also causes secretion from uterine gland
MRP SWINE
Controlled by Oestradiol
Day 10-11
Modificaiton of excretion of PGF2a
Endocrine Secretion
- Secretion of PGF2a = luteolysis
Exocrine secretion of pgf2a = luteotrophic
Blastocyst produces oestradiol = PGF2a rerouted into uterine lumen, where it is destroyed, thus preventing luteolysis
Equine MRP
Presence and migration of the conceptus
Conceptus is spherical with a capsule
Trans uterine migration must occur 12-17 times per day between day 12-14 to prevent luteolysis
Conceptus does also produce proteins which have an effect on maternal recogniition
Gestation
Process of carrying or being carried in the uterus
Attachment
Formation of a transient relationship between chorion of the conceptus and the endometrium (domestic species)
Implantation
Conceptus buries itself into the endometrium (primates, rodents)
Placental classification
Based on layers - tissues layers seperating fetal and maternal blood
Chorionic villi
Chorionic villi
Functional unit of fetal placenta
Finger like projections
Exchange apparatus = increase surface area
Layers
Chorionic capillaries, interstitium, epithelium
Layers only lost from maternal side - prefix
Classification
Diffuse - mare and sow
ZOnary - dogs and cats
Discoid- rodents and primates
Cotyledonary - ruminants
Ruminant placenta
epitheliochorial (syndesmochorial)
Binucleate Giant cells
Ruminants
Secrete placental lactogen
Secrete pregnancy specific protein
Secrete oestradiol and progesterone
