repro 7 Flashcards
what are the stages from fertiliztion –> implantation in the endometrium?
a. secondary oocyte is fertilized
b. zygot
c. cleavage (2-celled –> 4-celled –> 8-celled)
d. morula 72hours later
e. blastocyst —-> implants 6 days later
blastocyst
-100 cells
trophoblast cells surround the inner mass cells
-implants about 7 days after ovulation
-when comes into contact with endometrium, it proliferates and secretes enzymes wich allow it to penetrate the wall
what is the chorion?
the outer cells mass of the blastocyst
chorionic villi (fingers) penetrate the endrometrium and collects blood from mom (intervillous space) formed by trohpoblasts
what is the amnion?
secretes amniotic fluid wich protects the embryo
what is the allantois?
becomes the umilical cord
Human Chroionic Gonadotropin HCG
released by the corpus luteum and corionic villi which keeps corpus luteum alive and producing hormones until balstocyst is impolanted.
then, the placenta takes over production of these secretions
Hormones that the Placenta produces*
Proesterone and Estrogen
-negative feedback to HPG axis which prevents follicle development
-estrogen: develops milk secreting ducts
-Proestrogen: maintains endometrium, supresses contractions
*Human placental lactogen (hPL)or(hCS)
-alters mothers glucose and fatty acid metabolism to support fetal growth
trophoblast layer
forms the chorion
Parturition: the birth process
the birth process
occurs around th 40th week (we dont know why it is triggered) could be release of CRH
-begins with labor (rythmic contractions of the uterus)
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Parturition: days prior
-softening of ligaments that hold pelvic bones together looses under enzymatic control
-
mammary glands
proestrogen and estrogen actually inhibit milk production. So COLOSTRUM is used instread
milk production is controlled by PROLACTIN which comes from pituitary gland and can by inhibited by PROCATIN INHIBITORY HORMONE (PIH)
Oxytocin causes milk ejection
