Lecture 19: Breast Flashcards
What are breasts?
Purpose of breasts
Mammary glands
Purpose
1) Feeding babies
2) Contraception
Describe how the breast is derived
- Mammary glands are modified sweat glands
- They are derived from tissue that is first identified in the mammary (or milk) crests that arise between the axilla and the groin
- Breast development begins with the formation of mammary buds at abou_t 6 weeks_
- The first development takes place as a d_own growth_ of the dermis to form the primary breast bud
-
Secondary buds develop from the pirmary bud
- These secondary buds will become the lactiferous ducts
- Under the influence of the steroid homrone, the buds develop lumens (become canalised
- oestrogen and progesterone
- By birth_, 15-20 lactiferous ducts_ are present
Mammary glands are _______
Mammary glands are modified sweat glands
secondary buds will become the _______
secondary buds will become the lactiferous ducts
When are the breasts fully developed?
At birth, the breasts are fully developed and could potentially make milk
Milk production would require hormonal stimulus
Because the fetus has been exposed to the placental steroids and maternal hormones at birth some babies do make colostrium like secretion called withc’s milk.
What is the word for…
noncancerous increase in the size of male breast tissue
Gynaecomastia
Describe the External structure of the breast
External structures:
1) Areola
- Pigmented circle of tissue surrounding the nipple
- Contains sebaeceous glands which give a granular texture to the surface
2) Body of breast - many different shapes
3) Nipple
- Raised (usually) cylindrical pigmented structure
- Can be inverted - common
- The lacterferous ducts join the skin at the nipple
Describe the Internal structure of the breast
1) Adipose tissue of the _pectoral fat pad (_major component)
- Fat gives the breast its texture and much of its shape
2) Breasts are supported by ligaments called the suspensory ligaments of Cooper or Cooper’s ligaments
- these ligaments are affected by age and hormones in pregnancy can become less supprotive
Breasts are supported by _________
Breasts are supported by ligaments called the suspensory ligaments of Cooper or Cooper’s ligaments
Describe the lobes of the breast
- The human breast contains 15-20 lobes each made up of milk secreting lobules
- Each of the lobules connects to a single lactiferous duct
- These structures look a little like a bunch of grapes
- The lactiferous duct runs towards the nipple and expands into a l_actiferous sinus (_broadening of the lactiferous duct)
- The laciferous sinuses (15-20) open onto the nipple and allow extraction of the milk
The human breast contains _____ lobes each made up of ___________
The human breast contains _15-20 l_obes each made up of milk secreting lobules
Each of the lobules connects to a ________________
Each of the lobules connects to a single lactiferous duct
The lactiferous duct runs towards the nipple and expands into a _______
The lactiferous duct runs towards the nipple and expands into a lactiferous sinus
Describe the hormonal influences on breast milk production
- Until puberty, the breast ducts don’t have alveoli- these start to develop during puberty, particualrly under the influence of oestrogen
- During the mentrual cycle, oestrogen and progesterone promote the growth University Entrance Exams_of alveolar buds_- successive cycles cause increased growth
- The steroids, particularly progesterone seem to prevent major milk production
- Progesterone is also a s_mooth muscle relaxant_ and prevents milk ejection
Until puberty, the breast ducts don’t have ____- these start to develop during puberty, particualrly under the influence of _____
Until puberty, the breast ducts don’t have alveoli- these start to develop during puberty, particualrly under the influence of oestrogen