In what week in fetal development do mammary ridges form?
What do mammory rigdes form from?
What hormonal action leads to the formation of fetal breast development
Placenta-induced high levels of oestrogen in foeatal plasma levels
In what week do primary buds form in foetal breast development?
In what month do secondary buds for in foetal breast development?
What is the subsequent step in fetal breast development following secondary bud development?
Canalisation- – lactiferous ducts, open onto mammary pit – nipple. Alveolar formation and even milk secretion (witches milk) may occur in new-born infant – prolactin.
What percentage of breast nodules have symptoms of galactorrhea at birth?
Which hormones influence pubertal breast growth
Oestrogen and progesterone
Enlargement of the breasts during puberty is mainly due to...
- fat deposition
- interlobular and intralobular connective tissue
- formation of more ducts by branching
What is gynecomastia?
Breast development in men
What causes gynecomastia?
Increased oestrogen and out of balance testosterone in men
What layer of the chest do the breasts reside?
What glands are located in the areola??
Sebaceous and sweat
What are the modified sweat glands of milk production (2).
Merocrine glands - protein leaving alveoli
Apocrine glands - lipids leaving alveoli
What paths do the arteries and veins to the breast tissue follow?
Path of the milk ducts
What arteries supply the breasts and what area of the breasts to they supply?
Subclavian artery – internal thoracic (perforating branches) – medial mammary branches.
Axillary artery – lateral thoracic – lateral mammary.
Small branches of the anterior and posterior intercostal.
Describe the venous drainage of the breasts
Most venous drainage is to the axillary vein, and the internal thoracic vein.
Describe the lymphatic system in relation to the breasts.
Ducts located in the connective tissue surrounding the alveoli.
Lymph drains from the nipple, areola and ducts to a subareolar lymphatic plexus. From there 75% of drainage drains to axillary and supra clavicular lymph nodes (lateral breast), and the parasternal lymph nodes (medial breast).
What percentage of lymph drains from the subareolar lyphatic plexus to the axillary, supraclavicluar lymph nodes and the parasternal lymph nodes?
What is the clinical significance of the lymphatic drainage of the breast
Lymphatic drainage of the breast is important due to its role in metastasis of cancer cells in the breast. Cancer cells typically spread via lymph. Interference of lymphatic drainage by cancer cells can lead to lymphedema.
Which intercostal nerves and braches of these intercostal nerves supply the breasts?
Anterior and lateral branches of the 2nd to 6th intercostal nerves.
What does the autonomic nerves to the breasts control?
- Efelx secretion of prolactin and oxytocin.
Smooth muscle of alveoli = blood flow = engorgement and erection
- Myoepithelial cell contraction = let down reflex.
How many irregular lobes of breached tubuloalveolar glands make up the post-pubertal breast?
What aremammary gland lobules seperated by?
Connective tissue septae (suspensory/Cooper's ligaments) radiating fromthe nipple.
What is the function of th suspensory/Cooper's ligaments of the breasts?
• connect breast to muscle fascia (pec major & ser ant) beneath and dermis above
• provide support
• passage for blood, nerves, lymph
• maintain firm and standing appearance, loosen with age
Where is adundant adipose tissue located in the post-pubertal breast?
Interlobular spaces but much less in the intralobular connective tissue.
All interlobular ducts of each lobe end in one ...
Lactiferous duct opening at the nipple.
Describe the epithlial types of the duct system of the breasts.
Simple cuboidal/columnar = Epithelium starting at alveoli
Two layers cuboidal = lactiferous sinus
Stratified squamous = terminal lactiferous duct
What is the order of structures in the ductal system of the breast from deep-> superficial?
Alveoli < intralobular duct < interlobular duct < lactiferous duct < sinus
An alveolus of the breast is composed of:
Single layer of secretory (cuboidal/columnar) epithelial cells
Myoepithelial cells between epthelial cells and basement memebrane.
Lumen of alveolar ducts