Histology 2 - Histology of the Breast Flashcards
What type of structure is the breast?
A gland
What layer of the body is the breast located in?
Subcutaneous - sits anterior to the fascia on the anterior wall of the chest
How many lobes makes up the secretory tissue of the breast?
15-25
Describe the basic structure of a breast lobe?
Compound tubulo-acinar gland which drains into a series of ducts leading to the nipple
What is found adjacent to secretory lobules in the breast?
What is this surrounded in?
Dense fibrous tissue
Adipose tissue
What is the name for the pigmented area around the nipple?
Areola
What are lobes of the breast made up of?
Lobules
What is the name for the space between the breast and pectoralis major?
Retromammary space
What is the name for the larger condensations that extend from the dermis of the skin to the deep fascia overlying the muscle of the anterior chest wall in the non-lactating breast?
Suspensory ligaments
What is the purpose of suspensory ligaments?
To support the breast
What is the name of the basic functional secretory unit of the breast?
Terminal duct lobular unit (TDLU)
What is another name for terminal ductules?
Acini
In a non-lactating breast, what do terminal ductules lead into?
An intralobular duct
What do intralobular collecting ducts lead into?
Lactiferous duct (for that lobe)
What do the lactiferous ducts lead to?
The nipple
What is the name for the expanded duct region near the nipple?
Lactiferous sinus
What surrounds the acini within the lobule?
What does this allow?
Looser connective tissue
Rapid expansion in pregnancy
What type of cells are the secretory epithelial cells lining the acini within the lobule?
Vary from cuboidal to columnar
What surrounds the secretory cells of the acinus?
Myoepithelial cells (MEp)
What are the myoepithelial cells surrounded by?
The basal lamina
What are the purpose of the myoepithelial cells?
Helps to push the milk out
What type of epithelium lines larger ducts, such as a lactiferous duct?
Varies from a thin stratified squamous epithelium to a stratified cuboidal epithelium (becomes squamous as you get closer to the nipple)
Are myoepithelial cells present in larger duct, such as a lactiferous duct?
Yes
What do many people believe the origin of mammary glands is?
Modified sweat glands
Does the nipple have a smooth or wrinkled surface?
Wrinkled
What type of epithelium covers the nipple?
A thin, highly pigment keratinised stratified squamous epithelium
Describe the core of the nipple.
Dense irregular connective tissue mixed with bundles of smooth muscle
What type of glands are present in the nipple?
Where do these end?
Sebaceous glands
On the surface of the skin
What happens to the breast during the luteal phase of the menstrual cycle`?
Epithelial cells increase in height
Lumina of the ducts become enlarged
Small amounts of secretions appear in the ducts
What happens to the breast during the first trimester of pregnancy?
Elongation and branching of the smaller ducts, combined with proliferation of the epithelial cells of the glands and the myoepithelial ccells
What happens to the breast during the second trimester of pregnancy?
Glandular tissue continues to develop with differentiation of secretory alveoli
Plasma cells and lymphocytes infiltrate the nearby connective tissue
What happens to the breast during the third trimester of pregnancy?
Alveoli continue to mature, with development of extensive rER
What does oestrogen and progesterone stimulate to happen during pregnancy?
Proliferation of secretory tissue
Fibro-fatty tissue to become sparse
What is the approximate composition of human milk?
88% water
1.5% protein (mainly lactalbumin and casein)
7% carbohydrate (mainly lactose)
3.5% lipid
Small quantities of ions, vitamins and IgA antibodies
Describe the method by which lipid droplets are secreted into breast milk?
Apocrine secretion
Where are the proteins in milk made?
The rough endoplasmic reticulum
Name the method by which protein is secreted into breast milk?
Merocrine secretion (aka exocytosis)
What happens to the terminal duct lobular unit following menopause?
The secretory cells of the TDLU’s degenerate leaving only ducts
What happens to the connective tissue of the breast following menopause?
Fewer fibroblasts and reduced collagen and elastic fibres
