The mammary glands

Physiology

The mammary glands are exocrine glands which produce milk (galactopoiesis) in response to prolactin signals from the hypothalamus and pituitary gland.

Milk is released from the glands, through the ducts and out through the nipples (lactation) in response to oxytocin signals from the hypothalamus and pituitary gland. Stimulation of the nipples (as in breastfeeding), triggers the release of more oxytocin, which facilitates the ejection of more milk. This is known as the 'milk ejection reflex' or the 'let-down reflex'.

 

Pathophysiology

In women with poor breastfeeding technique, there may be insufficient liberation of milk from the ductal system of the breasts. This allows milk to remain in the ducts and glands, which allows time for bacteria to proliferate. This results in mastitis and potentially more severe infections such as breast abscess.

 

Hormones

• Stimulated by: Prolactin (PRL)
• Action: Stimulates milk production in the mammary glands

• Stimulated by: Oxytocin 
• Action: Stimulates milk ejection from the mammary glands