Breast Development

Question 1

What is the relationship between breast feeding and breast cancer?

Answer 1

Breast feeding is protective against breast cancer, but this effect occurs many years after breastfeeding

Question 2

Describe the anatomy of a mammary gland lobule

Answer 2

Secretory epithelial cells around a central lumen, surrounded by myoepithelial cells.

Question 3

Compare the composition of lactating and non-lactating breats

Answer 3

Lactating breast has…

• More mammary gland tissue
• Less intraglandular fat

when compared to a non-lactating breast

Question 4

When is the rudimentary mammary gland established?

Answer 4

• Rudimentary mammary gland is established during embryogenesis

Question 5

What germ layer is the mammary gland?

What hormone mediates this differentiation?

Answer 5

• Mammary gland is ectoderm that invaginates within mesoderm
• PTHrP induces this tissue specialization

Question 6

Describe Tanner Stages 1-5 in women

Answer 6

1. No sexual hair. Flat chest with raised nipple
2. Pubic hair appears. Breast bud forms
3. Pubic hair coarsens. Breast mound forms
4. Public hair is across pubis, sparing thigh. Breast has raised areola.
5. Pubic hair spreads to medial thigh. Areola flattens.

Question 7

What tissue grows to cause breast enlargement during puberty?

Answer 7

Fat accumulation

(not glandular development)

Question 8

• Puberty
  
  • ____ and ___ cause growth of the ____
• Menses
  
  • ______ causes growth of _____
• Pregnancy
  
  • ______ and ____ needed for full maturation of _____

Answer 8

• Puberty
  
  • Estrogen and GH cause growth of the ducts
• Menses
  
  • Progesterone causes growth of alveoli
• Pregnancy
  
  • Progesterone and PRL needed for full maturation of alveoli

Question 9

What hormone(s) causes breast development during puberty?

Answer 9

GH and estrogen

(cause duct growth)

Question 10

What effect does progesterone have on breast tissue?

Answer 10

Progesterone causes alveolar development & branching during menses

Question 11

What changes occur in the breast during pregnancy?

What hormones cause this?

Answer 11

Pregnancy -> maturation/development of alveoli

Due to progesterone and PRL

Question 12

Name 3 hormones involved in milk secretion at partuition and their roles.

Answer 12

• Milk secretion is initiated by PRL and placental lactogen
• Milk secretion is no longer inhibited by progesterone once placenta is gone

Question 13

Why don’t pregnant women lactate?

Answer 13

Progesterone suppresses lactation

(plenty of PRL is present)