Page 904 - Atlas of Histology with Functional Correlations

The fetal portion includes the chorionic plate and its villi

Maternal part includes the decidua basalis layer of endometrium
Anchoring villi arise from chorionic plate and attach to decidua basalis
Maternal blood enters intervillous space to bathe villi that contain fetal blood
Regulates exchange of vital substances between maternal and fetal
circulations

Cells secrete the hormone human chorionic gonadotropin shortly after
pregnancy
Human chorionic gonadotropin appears in urine and is used for pregnancy

tests
Human chorionic gonadotropin stimulates corpus luteum to secrete estrogen
and progesterone and other substances
Takes over function of corpus luteum until birth

MAMMARY GLANDS

Before puberty, they consist primarily of lactiferous ducts that open at the

nipple
Inactive glands contain connective tissue and ducts, surrounded by
myoepithelial cells
Estrogen and progesterone induce growth in females, forming tubuloalveolar

glands
Development also depends on prolactin, placental lactogen, and adrenal
corticoids
During pregnancy, ducts branch, enlarge, and form terminal buds with

alveoli
Late in pregnancy, alveoli contain some secretory products, but not milk
At the end of pregnancy, alveolar secretion is colostrum, rich in proteins and
antibodies

During lactation, some alveoli are distended with secretory material
containing more fat
After placenta eliminated, prolactin activates milk secretion
Suckling of nipple releases oxytocin, causing myoepithelial contraction and

milk release

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