W7 Placentation Flashcards
Placenta secretes hormones for 3 reasons
- Maintenance of pregnancy
- Stimulation of the maternal mammary gland
- ensures fetal growth
Final prepartum steps of repro
Formation of a placenta
Aquisition of endocrine function of placenta
Initiation of parturition
Placenta
Oran for metabolic exchange
Transitory endocrine organ
Placental exchange mechanisms
Simple diffusion - gas and water
Facilitated diffusion - glusose and amino acids
Active transport - placenta has active transport pumps for Na, K, Ca
Placental Functions
Stimulate ovarian Function
Maintain pregnancy
Influence fetal growth
Stimulate mammary function
Assist in parturition
Effect of placenta on ovarian function - mare
eCG or PSMG
Maintains primary CL
LH like action in equine - LH and FSH in other species
Effect of placenta on ovarian function - human
hCG
Secreted from trophoblastic cells of chorion
LH like action in other secies
Palcenta secretes what
Progesterone and Oestrogen
Placental progesterone
P4 increasese secretion of endometrial glands = early embryonic development
p4 = progesterone block = prevents myometrial contractions
Placental Oestrogen
Important during last part of gestation
Responsible for the physiological and morphological changes
mammary finction and fetal growth
Placental lactogen(somatomammotrophin) -HGH
Promotes growth
Relaxin secreted from where
Secreted by placenta
Synthesise is stimulated by PGF2a
CL of pregnancy produces relaxin in cows
Relaxin function
Softening of connective tissue in cervix
Relaxation of pelvic ligaments
Pregnancy diagnostic in bitch
Mrphological Changes
Abdoment enlargement
Mammary gland bigger and milk
Vulva swell
Behavourial changes
Avoids aggressive behavior
Avoids socialisation
Restless
