1. Institutt for medisinske basalfag
Placenta Histology
Histology 4: The Female Reproductive System: Placenta and Mammary Gland
Per Brodal
Institutt for medisinske basalfag
Universitetet i Oslo
9th Semester 2008

2. Endometrium: Secretory Phase
Glands with typical secretory phase appearance
Stroma with pronounced decidual reaction, especially close to the implantate:
Stroma edematous
Stromal cells (modified fibroblasts) large and pale-staining due to a high content of glycogen and lipids (secreted to support the implantate)
Several cell-types of the maternal immune system are likely present without showing with the present technique
”Clusters” of transverse and oblique sections of spiral arteries (one artery may be sectioned more than once)
Look for remodelled spiral arteries with thin walls
Per Brodal 2008

3. Endometrium: Secretory Phase
Per Brodal 2008

4. Spiral arteries Low Power
Field seen in next slide
Per Brodal 2008

5. Spiral Arteries in the Endometrium
May try to find remodeled arteries with thin walls due to erosion by the trophoblast
Per Brodal 2008

6. Implantate: Decidual reaction
Stroma with pronounced decidual reaction, especially close to the implantate:
Stroma edematous
Stromal cells (modified fibroblasts) large and pale-staining due to a high content of glycogen and lipids (secreted to support the implantate)
Per Brodal 2008

7. Decidual Reaction, Close up
Large, rounded decidual cells with pale cytoplasm and large, pale nuclei.
Speilegg=fried egg Dominated by large, rounded decidual cells with pale cytoplasm and large, pale nuclei.
Per Brodal 2008

8. Implantate Secondary villi Endometrium Intervillous spaces
Per Brodal 2008

9. Implantate, Enlarged Extra-embryonic mesoderm in villus
Cytotrophoblast
Syncytiotrophoblast
Intervillous space
Per Brodal 2008

10. Feto-maternal transition zone
Extravillous trophoblasts: Variable size, form & staining density of nucl & cytopl, infiltrates among the decidual cells, ”malignant Look
Syncytiotrophoblast with lacunae
Decidual cells (light, regular
Chorion
Decidua
Extravillous trophoblasts
Per Brodal 2008

11. Implantate, Close Up Syncytiotrophoblast Cytotrophoblast
Extra-embryonic mesoderm (mesenchym)
Per Brodal 2008

12. Placenta (~ 6 weeks) Stem villus Chorionic villus Chorionic plate
Chorionic cavity
Chorionic plate
Chorionic villi
Extraembryonic mesoderm with blood vessels containing fetal cells (erythrocytes nucleated )
Cytotrophoblast
Syncytiotrophoblast
Intervillous spaces
The intervillous spaces are empty in this specimen (maternal blood washed out during preparation)
No maternal tissue in this section
Chorionic plate
Per Brodal 2008

13. Intervillous space (maternal blood)
Syncytiotrophoblast
Cytotrophoblast
Capillary
Intervillous space (maternal blood)
Per Brodal 2008

14. Brush border (microvilli) on syncytiotrophoblasts
Villus with capillary
Brush border (microvilli) on syncytiotrophoblasts
Capillary
(Fetal erythrocytes nucleated)
Per Brodal 2008

15. Umbilical Artery
Mesenchyme
Arterial wall
Per Brodal 2008

16. Mesenchyme (Umbilical Cord)
Per Brodal 2008

17. Mamma and the Mammary Gland
Per Brodal 2008

18. Mammary line Langman Proliferation of epthelial cells (mammary ridge)
Epidermis
Mesenchyme
Positions of accessory nipples
Mammary line
The mammary glands are modified sweat glands situated in a specially developed subcutaneous fatty tissue
The epithelial components develop from the ectoderm
15-20 separate ectodermal ”buds” develop from papilla mammae
Each bud develops into one ductus lactiferus, to drain one mammary lobe
All mammalian embryos transiently show a ”mammary line” (Norw: Melkelist) between the axilla and the inguinal region. This explains that
Many mammals normally have > 2 mamma
Humans may have supernumerary nipples and accessory mammary tissue
The human mamma normally has an ”axillary tail”
Lactiferous duct (15-20)
Langman
Per Brodal 2008

19. Mamma Pectoral muscle Adipose tissue (lobulated) Ductus lactiferus
Sinus lactiferus
Areola
Glandular tissue
At birth, sparsely branched ductus lactiferus are present. Due to strong hormonal stimulation in utero, the ducts of the newborn (both sexes) may produce a sparse secretion (”witch’s milk”)
In females at puberty the duct system and adipose tissue develop to give the mammary gland its mature resting form
During pregnancy, the duct system expands and secretory units (alveoli) develop
Right after delivery, secretion starts
When lactation is terminated, the alveoli and ducts regress to the pre-pregnant stage
After the menopause, the duct system gradually regresses
Suspensory ligaments
Papilla mamma
Per Brodal 2008

20. Mammary gland from a child
Ductus lactiferus
Per Brodal 2008

21. Resting mammary gland (adult)
Interlobular connective tissue
Terminal duct
15-20 separate ductus lactiferus ( dl ) extend from the papilla mamma into the subcutaneous fatty tissue
The opening of each duct on the papilla is about 0,5 micrometer and macroscopically visible
Below the areola, each dl is dilated: sinus lactiferus
Ductus lactiferus are lined with 2-layered epithelium
Each dl branch several times (the epithelium is reduced in height and to 1 layer)
Each terminal branch enters its own lobulus and divides into several intralobular ducts (ductuli)
A terminal duct with its lobulus (terminal ducto-lobular unit) measures about 1 mm in the resting mamma (Geneser)
Most of the volume of the resting mamma is contributed by fatty tissue
Intralobular ct is loose and vascular
Interlobular ct is quite dense
Interlobar ct, especially in the upper part of the gland, is dense and forms strong connections between the skin and the muscle fascia over pectoralis major and serratus anterior, ”suspensory ligaments ” (”of Cooper”)
Tumors can cause ”dimples” in the skin, and asymmetry btw the mammae, by pulling on interlobar ct
Lobuli
Per Brodal 2008

22. Lactating gland Alveoli Duct Per Brodal 2008
Lactation induced by prolactin from the pituitary and somatomammotropin from the placenta
Per Brodal 2008

23. Lactating Gland: Alveoli in Different Phases
Producing
Storing
During the first part of the pregnancy intralobular ducts branch richly
Later, alveoli develop with secretory and myoephithelial cells
Connective and fatty tissue are gradually reduced to almost nothing, but the net effect is increased size of the mammae.
In late pregnancy increased height of secretory cells and accumulation of secretion (colostrum, rich in IgA) in the alveoli accounts for the increased volume of the gland
A lactating mammae shows lobuli in different phases
Alveoli just starting to secrete have small, empty luminae and high epithelial cells
Alveoli not actively secreting, but storing, milk have large lumen and flattened epithelial cells
Per Brodal 2008

24. Mammary Secretory Cell
Lipids
Composition of milk:
Water 88 %
Carbohydrates (lactose) 7 %
Fat 4 %
Proteins 1 %
Proteins
Bloom and Fawcett (fra Ross and Reith)
Composition of the milk: colostrum, protein-rich,IgA, sticky; produced in the later stage of the pregnancy
Mature milk:
Colostrum: the first milk; rich in protein, IgA. Production starts last month of pregancy
Bloom and Fawcett
Per Brodal 2008

25. Myoepithelial Cells Around Alveoli
Secretory cells
Per Brodal 2008

26. Papilla mammaria Papilla Lactiferous duct (sinus) Areola
Placenta Histology
Papilla mammaria
Papilla
Lactiferous duct (sinus)
Areola
Per Brodal 2008

27. Papilla mammaria (mammae)
Sebaceous glands
Smooth muscle in the papilla ”erect” it when the baby suckles
Rich sensory innervation of the papillae is part of the afferent limbs of reflexes which, when the baby suckles, cause:
Erection of the papilla
Prolactin production and release from the hypothalamo-hypophyseal system (anterior h. lobe) to stimulate secretion of milk by the aveolar cells
Oxytocin production and release from hypothala-hypophyseal system (posterior h. lobe) to stimulate ejection of milk by the contraction of myoepithelial cells
Reddish colour due to well developed dermal papilla (colour of blood shines through thin epidermis)
Variably pigmented, more during pregnancy
Ductus lactiferus
Per Brodal 2008

28. Papilla mammae Ductus lactiferus Bundles of smooth muscle
Per Brodal 2008

29. Milk Ejection Reflex Sensory stimuli from the nipple
Reaches the hypothalamus
Release of oxytocin from the posterior pituitary
Contraction of smooth muscle cells
Psychic influences
Psychic: milk ejection by hearing the baby, or by just thinking of it
Reduced milk production due to distress, depression etc..
Per Brodal 2008

30. Lymphatic Drainage Benninghoff
Main outflow: to axillary (75 %) and parasternal lymph nodes
2: deep cervical lymph nodes
1: deep axillary
4: superficial axillar
Benninghoff
Per Brodal 2008