This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Milk ejection is facilitated by: March 2007, March 2013 
Select and explain. 
A. Oxytocin, B. Growth hormone, C. FSH, D. LH
A: Oxytocin
Answer: A: Oxytocin 
Explanation: Ans. A: Oxytocin Hormonal control of Breast development and secretion and ejection of milk Progesterone -- influences the growth in size of alveoli and lobes. Oestrogen -- stimulates the milk duct system to grow and become specific. Follicle stimulating hormone Luteinizing hormone Prolactin -- contributes to the increased growth of the alveoli during pregnancy and formation of milk Oxytocin -- oxytocin contracts the smooth muscle layer of band-like cells surrounding the alveoli to squeeze the newly-produced milk into the duct system. Oxytocin is necessary for the milk ejection reflex, or let-down to occur. Human placental lactogen (HPL) --This hormone appears to be associated with breast, nipple, and areola growth before bih. Colostrum contains higher amounts of white blood cells and antibodies than mature milk, and is especially high in immunoglobulin A (IgA), which coats the lining of the baby's immature intestines, and helps to prevent germs from invading the baby's system.