The milk-forming reflex, along with the milk ejection reflex, is one of the lactation reflexes that mammals use to nourish their offspring and are stimulated by direct contact with the offspring. For the lactation reflex, the hormone prolactin from the anterior lobe of the pituitary gland plays the main role. In the case of hormone deficiency, the reflex is characterized by disturbances.
What is the milk-forming reflex?
Schematic diagram showing the anatomy and structure of the female breast. Click to enlarge. Like all other mammals, the female of the human species is equipped with glands for milk production. From an evolutionary biological point of view, the so-called milk cells ensure the supply and thus the survival of the offspring. Milk formation is a reflex triggered during pregnancy and the subsequent lactation period. In the breastfeeding phase, the triggering stimulus corresponds primarily to the touch stimuli during breastfeeding. The infant’s sucking movements lead to increased secretion of the hormone prolactin, which originates from the anterior pituitary gland. Prolactin stimulates lactogenesis, i.e. the formation of milk in the milk cells. The milk formed is stored in the alveoli, milk ducts and cisterns of the glands. The release of the stored milk occurs as part of the milk ejection reflex. Together with the lactation reflex, the milk ejection reflex is one of the so-called lactation reflexes. Ultimately, the milk formation reflex is the basis for the milk ejection reflex. Only the milk ejection reflex stimulates further milk formation. Thus, there is an interacting relationship between the lactation reflexes.
Function and task
The milk-forming cells, or alveoli, are located in the glandular vesicles within the glandular lobules of female breasts. The glandular lobules are part of the glandular tissue and thus form a large portion of the mammary glands, which are composed of individual mammary complexes. Lactation takes place in the alveoli by strangulation. In this process, the epithelium releases its own cell capsules into the lumen of the glands. This process is known as apocrine secretion. Nutrients such as vitamins and minerals reach the alveoli via the arteries and veins. Individual components of milk are formed by the secretory cells of the epithelium, such as lactose, milk fat and milk protein. The nutrients formed in this way are collected in the cytoplasm of the secretion cells and from there pressed into the lumen. Milk formation is subject to control by the pituitary hormone prolactin. During pregnancy, increased prolactin is produced in the anterior pituitary due to estrogens. Due to the suckling stimulus of the infant, the hormone is massively released during lactation. This release initiates the milk-forming reflex. Milk formation is a process determined by the principle of supply and demand. This means that the more the infant drinks, the more milk formation is stimulated by the suckling stimulus. If, on the other hand, the offspring drinks little or is not breastfed at all, hardly any milk production takes place. Relevant for the release of stored milk from the mammary glands is the hormone oxytocin, which is also released during contact with the infant. Thus, contact between mother and infant and the associated touch stimuli play the main role for all lactation reflexes. There is an interaction between the lactation reflex and the milk ejection reflex. Without one, the other reflex cannot ultimately take place in the. Thus, not only the lactation hormone prolactin, but also the milk flow hormone oxytocin is required in some concentration for healthy milk formation within the lactation reflex. The same is true in the opposite direction.
Diseases and ailments
After pregnancy, women sometimes feel that they are not producing enough milk to feed their offspring. In most cases, insufficient milk production is not due to physical inadequacies, but to errors in breastfeeding. For example, if the infant is not latched on often enough to breastfeed, fewer hormones are released. In addition, milk engorgement can occur in individual cases. In this condition, sufficient milk is produced as part of the lactation reflex, but the milk can no longer be delivered. In addition, the sucking reflex of infants is not always equally pronounced. If there is an insufficiently intense sucking reflex, sucking is not registered as such and milk formation fails to occur.The milk-forming reflex is additionally influenced by the mother’s psychological constitution. Strong stress, feelings of anxiety, hecticness, pressure or pain have a negative effect on lactation. Especially feelings of pressure are a common phenomenon after pregnancy. Many first-time mothers feel psychological pressure to live up to their new role as mothers. Only in extremely rare cases are physical ailments responsible for a disturbed lactation reflex. These physical conditions usually correspond to a hormonal deficiency of prolactin or oxytocin. In addition to a decrease in lactation reflexes, an increased lactation reflex may also have disease value. Milk production outside pregnancy and lactation is usually also due to dysregulation of the hormonal balance. However, psychological causes may also be present in this context. Causal diseases of the glands are also conceivable. In addition, benign tumors such as adenomas may produce hormones. This applies in particular to glandular tumors, which can disturb the hormonal balance with their hormone production. Overproduction of milk is sometimes noticeable in the form of unwanted milk flow. In individual cases, women also develop increased milk production with milk flow if they have a strong desire to have children.
