Decidua, chorion, placenta, umbilical cord.

Doc. MUDr. Marie Jirkovská, CSc.

Institute of Histology and Embryology

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Deciduaendometrium in pregnancy- decidua basalis - pars materna placentae

(endometrium)

schema

secretory phase

decidual cells

Chorion

B.M.Carlson: Human Embryology and Developmental Biology, 1999

Decidua basalis

Chorionic villi primary (P) secondary (S) tertiary (T)

P

PS

syncytiotrophoblast

cytotrophoblast

capillary

Hofbauer‘s cells

ChorionS - syncytiotrophoblast, C - cytotrophoblast, M - mesenchyme,

H - Hofbauer cells

H

M

C

S

Chorionic villi *proliferation and migration of cytotrophoblast, C – cytotrophoblast shell, V – chorionic villus, D - decidua

*

*

V

V

CC

D

Relationship of decidua and chorion

Human placenta at termDiscoid (diameter 15 – 20 cm, thickness 2 – 3 cm) – according shapeHemochorial villous – according structure Placenta consists of: fetal part (villous chorion) and maternal part (decidua basalis)

cotyledons

Human placenta at term – a scheme

Fetal part: chorionic plate and cotyledons consisting of one or more main stem villi and their branches.Maternal part: decidual plate is covered by syncytiotrophoblast, contains decidual cells and remnants of the cytotrophoblastic shell.

Placenta at low magnification

Stem and intermediate villi

Fibrinoid – eosinophilic mass on the surface of villi, decidua basalis and chorionic plate (material composed of fibrin from maternal blood and degenerated cells).

Placenta

Terminal villi Placental septum

syncytiotrophoblast

vasculosyncytial membrane

cytotrophoblast decidual cell

capillary

3-D reconstruction of the villous capillary bed

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Umbilical cordlength cca 50 cm

A – a. umbilicalis, V – v. umbilicalis, E – ectoderm of the amnion, W – Wharton‘s jelly

VA

W

E

E

W

A

V