IBLCE Anatomy and Physiology of Lactation 1 — Questions and Answers
Question 1: Which hormone is primarily responsible for milk synthesis and secretion in the lactating breast?
- Estrogen
- Prolactin (Correct answer)
- Oxytocin
- Progesterone
Correct answer: Prolactin
Prolactin, secreted by the anterior pituitary, is the primary hormone driving milk synthesis (lactogenesis) in the alveolar cells.
Question 2: Which hormone triggers the milk ejection reflex (let-down) by causing myoepithelial cells to contract?
- Prolactin
- Progesterone
- Oxytocin (Correct answer)
- Cortisol
Correct answer: Oxytocin
Oxytocin, released from the posterior pituitary, causes myoepithelial cells surrounding the alveoli to contract, ejecting milk into the ducts.
Question 3: The functional milk-producing unit of the breast is called the:
- Lobule
- Alveolus (Correct answer)
- Lactiferous sinus
- Montgomery gland
Correct answer: Alveolus
The alveolus is the microscopic sac lined with secretory epithelial cells (lactocytes) where milk is synthesized and stored.
Question 4: During pregnancy, high levels of which hormone inhibit full lactogenesis despite rising prolactin levels?
- Estrogen
- Progesterone (Correct answer)
- Cortisol
- Human placental lactogen
Correct answer: Progesterone
High progesterone levels during pregnancy block prolactin receptors on alveolar cells, preventing full milk production until progesterone falls after placental delivery.
Question 5: Lactogenesis II, the onset of copious milk production, typically occurs how many hours after birth?
- 6–12 hours
- 12–24 hours
- 30–73 hours (Correct answer)
- 96–120 hours
Correct answer: 30–73 hours
Lactogenesis II generally begins 30–73 hours postpartum, corresponding to the drop in progesterone after placental delivery and the surge in prolactin activity.
Question 6: The cells that surround alveoli and contract in response to oxytocin are called:
- Lactocytes
- Myoepithelial cells (Correct answer)
- Fibroblasts
- Ductal epithelial cells
Correct answer: Myoepithelial cells
Myoepithelial cells form a basket-like network around each alveolus and contract when stimulated by oxytocin to propel milk into the ductal system.
Question 7: Which breast structure opens onto the nipple surface and transports milk from the lobules outward?
- Cooper's ligaments
- Lactiferous ducts (Correct answer)
- Montgomery glands
- Ampullae
Correct answer: Lactiferous ducts
Lactiferous ducts channel milk from the lobular-alveolar units toward the nipple, where 15–20 duct openings release milk during feeding.
IBLCE Anatomy and Physiology of Lactation 1
Which hormone is primarily responsible for milk synthesis and secretion in the lactating breast?