CLE Anatomy & Physiology of Lactation 1 — Questions and Answers
Question 1: Which hormone is primarily responsible for milk ejection (let-down reflex)?
- Prolactin
- Estrogen
- Oxytocin (Correct answer)
- Progesterone
Correct answer: Oxytocin
Oxytocin is the hormone primarily responsible for the milk ejection reflex, also known as let-down. It causes the myoepithelial cells surrounding the milk-producing alveoli to contract, squeezing milk into the ducts and making it available to the infant. While prolactin stimulates milk production, oxytocin facilitates its release.
Question 2: Where does milk production occur within the breast?
- Areola
- Alveoli (Correct answer)
- Lactiferous sinus
- Ductal openings
Correct answer: Alveoli
Within the breast, milk production occurs in tiny, grape-like clusters of specialized cells called alveoli. These glandular cells synthesize milk from components in the mother's blood. The milk then collects in the lumen of the alveoli before being released into the duct system.
Question 3: What triggers the production of prolactin during breastfeeding?
- Infant crying
- Milk removal
- Infant suckling (Correct answer)
- Skin-to-skin contact
Correct answer: Infant suckling
The primary trigger for prolactin production during breastfeeding is the infant's suckling at the breast. This sensory input sends signals to the mother's anterior pituitary gland, which then releases prolactin. Prolactin is the hormone responsible for stimulating the mammary glands to synthesize milk.
Question 4: Which structure carries milk from the alveoli to the nipple?
- Lobules
- Areola
- Lactiferous ducts (Correct answer)
- Myoepithelial cells
Correct answer: Lactiferous ducts
After milk is produced in the alveoli, it travels through a network of small tubes called lactiferous ducts. These ducts converge and become larger, eventually carrying the milk to the nipple openings. This system ensures efficient transport of milk from its production site to the feeding infant.
Question 5: What role do myoepithelial cells play in lactation?
- Produce milk
- Store milk
- Transport nutrients
- Contract to eject milk (Correct answer)
Correct answer: Contract to eject milk
Myoepithelial cells are specialized cells that surround the alveoli and line the lactiferous ducts. When stimulated by oxytocin, these cells contract, squeezing the milk out of the alveoli and into the milk ducts. This action is essential for the milk ejection reflex, or 'let-down,' making milk available to the baby.
Question 6: What gland secretes oxytocin during lactation?
- Thyroid gland
- Adrenal gland
- Posterior pituitary (Correct answer)
- Anterior pituitary
Correct answer: Posterior pituitary
Oxytocin, the hormone responsible for the milk ejection reflex, is synthesized in the hypothalamus and then stored and released by the posterior pituitary gland. When an infant suckles or a mother thinks about her baby, signals are sent to the posterior pituitary, triggering oxytocin release into the bloodstream.
Question 7: What is colostrum?
- Watered-down breast milk
- Formula supplement
- First thick, yellowish milk rich in antibodies (Correct answer)
- Milk produced after 1 month
Correct answer: First thick, yellowish milk rich in antibodies
Colostrum is the first milk produced by the mother, typically in the first few days after birth. It is characterized by its thick, yellowish consistency and is incredibly rich in antibodies, immunoglobulins, and growth factors. Colostrum provides vital immune protection and concentrated nutrients for the newborn, acting as the baby's first immunization.
Question 8: What is the primary benefit of skin-to-skin contact after birth related to lactation?
- Increases infant alertness
- Delays crying
- Promotes hormone release for lactation (Correct answer)
- Helps baby sleep longer
Correct answer: Promotes hormone release for lactation
Skin-to-skin contact immediately after birth is crucial because it stimulates the release of oxytocin and prolactin in the mother. Oxytocin aids in uterine contractions and milk ejection, while prolactin promotes milk production. This hormonal cascade helps establish early breastfeeding and strengthens maternal-infant bonding.
Question 9: Which hormone is essential for milk synthesis in the breast?
- Insulin
- Prolactin (Correct answer)
- Testosterone
- Cortisol
Correct answer: Prolactin
Prolactin is the primary hormone responsible for milk synthesis, or the actual production of milk, within the mammary glands. It is released from the anterior pituitary gland in response to infant suckling and acts on the alveolar cells to stimulate them to produce breast milk. Without sufficient prolactin, milk supply would be inadequate.
CLE Anatomy & Physiology of Lactation 1
Which hormone is primarily responsible for milk ejection (let-down reflex)?