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Placentation, Gestation, & Parturition - Coggle Diagram
Placentation, Gestation, & Parturition
Placentation
Formation of placenta
Endocrine organ
Secretes hormones that
Stimulate mammary function
Maintain pregnancy
Assist in parturition
Stimulate ovarian function
Influence fetal growth
hCG
Provide luteotropic stimulus for CL
Progesterone
Elevated secretion by endometrial glands
eCG
Maintain CL
Estrogen
Signals early preparturient period
Placental lactogen
AKA somatomammotropin
Promote growth of fetus
Stimulate mammary gland
Hormones
Functional unit = chorionic villus
Exchange apparatus
Classified by distribution
Zonary
Band like zone
Ex.) Dogs and cats
Discoid
Form regionalized disc
Ex.) Rodents and primates
Diffuse
Uniform distribution that covers surface of chorion
Ex.) Pig
Ex.) Horse
Microcotyledons
Endometrial cups
Produce eCG
Cotyledonary
Numerous discrete button like cotyledons
Ex.) Ruminants
Ewe = concave
Cow = convex
Fetal cotyledon
Maternal cotyledon
Placental classification
Endotheliochorial = 5 layers
Complete erosion of endometrial epithelium and underlying interstitium
Ex.) Dogs and cats
Hemochorial = 3 layers
Chorionic epithelium in direct apposition to maternal blood
Ex.) Primates and rodents
Epitheliochorial = 6 layers
Complete intact layer of epithelium in maternal and fetal
Ex.) Sow and mare
Ex.) Ruminants
Syndesmochorial
Binucleate giant cells
Secrete placental lactogen
Secrete pregnancy specific protein B
Placental exchange
Facilitated diffusion
Glucose by carrier molecules
Major source of energy for fetus
Active transport
Na, K, and Ca by pumps
Simple diffusion
Gas and water from high to low
Gestation
Act of carrying between conception and birth
Pregnancy
Parturition
Promotes
Dilation of cervix
Expulsion of fetus
Myometrial contraction
Expulsion of extraembryonic membranes
3 stages
Expulsion of fetus
Requires strong myometrial and abdominal muscle contractions
Relaxin
Stimulated by PGF2a
Dystocia
Difficult birth
Expulsion of fetal membranes
Requires myometrial contractions
Initiation of myometrial contractions
Removal of progesterone block
Progesterone to estradiol
Synthesis of PGF2a
Initiated by fetus
Endocrine events
Uterine crowding
Increase fetal ACTH
Fetal cortisol
Enzymes
E2
Increase myometrial contractions
Increase pressure
1 more item...
Increase secretion by female tract
Lubrication
Placental P4
PGF2a
Luteolysis
Relaxin
Pelvic ligament stretching
