Lactation of suckling by the baby. The milk ejection reflex (also called let-down reflex) is not always consistent, especially at first. Once a woman is conditioned to nursing, let-down can be triggered by a variety of stimuli, including the sound of any baby. Even thinking about breastfeeding can stimulate this reflex, causing unwanted leakage, or both breasts may give out milk when an infant is feeding from one breast. However, this and other problems often settle after two weeks of feeding. Stress or anxiety can cause difficulties with breastfeeding. The release of the hormone oxytocin leads to the "milk ejection" or
Refractory period (physiology) cells, the cardiac action potential duration is closer to 100 ms (with variations depending on cell type, autonomic tone, etc.). After an action potential initiates, the cardiac cell is unable to initiate another action potential for some duration of time (which is slightly shorter than the "true" action potential duration). This period of time is referred to as the refractory period, which is 250ms in duration and helps to protect the heart. In the classical sense, the cardiac refractory period is separated into an absolute refractory period and a relative refractory period. During the absolute refractory period, a new action