milk letdown reflex

in mothers who are nursing, an automatic release of milk from sacs within the mammary glands in response to infant suckling or associated stimuli (e.g., the infant’s cry). The milk letdown reflex is regulated by the hormone oxytocin: Suckling stimulates the production of oxytocin, which in turn stimulates contractions of the smooth muscle myoepithelial cells surrounding the mammary glands, leading to the expulsion of milk from the sacs into ducts that converge on the nipples. The actual production of milk by the mammary glands is regulated by the hormone prolactin. Also called milk ejection reflex.

Browse dictionary by letter

a b c d e f g h i j k l m n o p q r s t u v w x y z

Psychology term of the day

December 18th 2024

homeostasis

1. the regulation by an organism of all aspects of its internal environment, including body temperature, salt–water balance (see osmoregulation), acid–base balance (see hydrogen-ion concentration), and blood sugar level. This involves monitoring changes in the external and internal environments by means of receptors and adjusting bodily processes accordingly. Compare tension law. [first described by Walter B. Cannon]

2. maintenance of a stable balance, evenness, or symmetry. —homeostatic adj.