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) potential cannot be elicited. During the relative refractory period, a new action potential can be elicited under the correct circumstances. The cardiac refractory period can result in different forms of "re-entry", which are a cause of tachycardia. Vortices of excitation in the myocardium (autowave vortices) are a form of "re-entry". Such vortices can be a mechanism of life-threatening cardiac arrhythmias. In particular, the autowave reverberator, more commonly referred to as spiral waves or rotors, can be found within the atria and may be a cause of atrial fibrillation. The refractory period in a neuron occurs after an action potential and