International Board of Certified Lactation Consultant (IBCLC) Practice Exam

What occurs when myoepithelial cells surrounding the alveoli contract?

1. The formation of colostrum

2. Milk ejection reflex

3. Increased milk production

4. Secretion of lactose

The correct answer is: Milk ejection reflex

The contraction of myoepithelial cells surrounding the alveoli is a crucial process in breastfeeding. Myoepithelial cells are specialized muscle cells located between the basal membrane and the epithelial cells of the mammary glands. When these cells contract, it leads to the milk ejection reflex, which is also known as the let-down reflex. This reflex is essential for the effective transfer of milk from the alveoli, where it is produced, into the ductal system, making it available to the nursing infant. The stimulation of the myoepithelial cells typically happens in response to hormones and signals from the infant’s suckling. When the breast is stimulated, oxytocin is released, which then causes the myoepithelial cells to contract and squeeze the milk out of the alveoli into the ducts. Consequently, this process is vital for successful breastfeeding, ensuring that the milk is readily available to the infant during feeding. While other options such as colostrum formation, increased milk production, and secretion of lactose are all significant aspects of lactation, they do not directly relate to the specific action of myoepithelial cell contraction and its immediate effect of facilitating the ejection of milk during breastfeeding. Thus, the milk