Histology of Mammary Gland and Placenta Flashcards
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Umbilical
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Placenta (First trimester)
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Mammary Alveoli
The placenta erodes into both the _________ and ______.
Endometrial glands; spiral arteries
What are the stages of placenta development?
- 7 1/2 day implanting blastocyst
- 9 day implanted blastocyst
- 16 day embryo
Function of chorionic villi?
Chorionic villi are villi that sprout from the chorion in order to give a maximum area of contact with the maternal blood
NOTE: Chorionic villi penetrate into endometrium
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Characteristics of placenta in first trimester
- Chorionic villi are large and covered by two layers of cells- cytotrophoblast and syncytiotrophoblast
- Blood vessels are not prominent
Characteristics of placenta in second trimester
- The villi becomes smaller
- More vascular
- Syncytiotrophoblast cell layer draws up into “syncytial knots” which are small clusters of cells, leaving a single cytotrophoblast layer
Characteristics of placenta in third trimester
- Branches of the umbilical vessels grow into the mesoderm
- In this way, the chorionic villi are vascularized to support the blood glas and nutrient exchange of maternal-fetal circulation
- Syncytial knots and intervillous fibrin are prominent
Which hormones are synthesizes by the placenta?
- hCG
- Somatommammotropin
- Progesterone
The syncytiotrophoblast is permeable to:
- Ions
- Nutrients
- Maternal IgG
- Some drugs
Which drugs have the highest fetal/maternal ratio?
Ketamine (1.26)
*This is an intravenous anesthetic
Which drugs have the lowest fetal/maternal ratio?
Lidocaine (0.5)
*This is a local anesthetic
Cause of pre-eclampsia
Elevated blood levels of a protein (sFIt-1) that binds growth factors required for normal placental growth
NOTE: Pre-eclampsia is a result of poor placental invasiveness and poor vascularization.
Components of milk secreted by mammary glands
- Lactose (Golgi)
- Protein (RER)
- Casein
- Lactoferrin
- IgA
- Lipid (cytosol)
- Triglycerides and cholesterol
- Antibodies (plasma cells)
- Ions
NOTE: Mammary glands contain 16-20 lobules
Stages in the functional anatomy of the mammary gland
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Nonpregnant
- Inactive duct system
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During pregnancy
- Alveoli proliferate at the ends of the ducts
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Lactating
- Milk secretion and accumulation in alveolar lumen
Differentiate between inactive and active mammary glands
In active:
- Amount of glandular tissues increases
- Involves both the epithelial and myoepithelial cells
- Proliferation of these cells leads to the formation of secretory alveoli
- Connective tissue decreases
- Increased cellularity of intralobular connective tissue
- Intralobular ducts have proliferated to form additional secretory regions
Characteristics of inactive mammary gland
- Abundant connective tissue
- Sparser glandular componnent consists largely of ducts
- Ducts are surrounded by loose connective tissue containing lymphocytes, plasma cells and fibroblasts
- Beyond a lobule is the connective tissue is more dense
- The dense connective tissue contains aggregates of adipocytes
Which type of epithelium line the laciferous ducts?
Stratified squamous epithelium
Which type of epithelium line the laciferous sinus?
Stratified cuboidal epithelium
*The remainder of the duct system is lined by a single layer of columnar or cuboidal cells
Myoepithelial cells are of _________ origin.
Ectodermal
NOTE: Myoepithelial cells lie within the epithelium between the surface epithelial cells and the basal lamina. They are present in the ductal and secretory portion of the gland
Inactive vs Proliferating vs Lactating Histology
Milk secretion depends on the action of which two epithelial cell types?
Myoepithelial cell
- Contract to aid in the ejection of milk
Luminal Epithelial cell
- Secrete the milk into the ductal lumen
What are the methods of milk secretion?
Mecrocrine
- Secretory vesicles coalesce with the membrane on the apical surface to release the product
- Protein component
Apocrine
- Lipid droplets pass to the apical region of the cell
- Droplets are invested with an envelope of plasma membrane and a thin layer of cytoplasm as they are released into the lumen of the acini
- Lipid component
