Apply Your Knowledge Of Breast Anatomy To The Physiology Of Lactation

Question 1

Explain lactogenesis

Answer 1

Milk is synthesised in the acini cells (lactocytes) under the influence of the hormone prolactin.

Milk is synthesised from glucose and amino acids in the blood stream.

Milk is secreted from the acini cells (lactocytes), across the cell membrane, into the lumin of the alveoli.

Question 2

Explain initiation of lactation : prolactin orders milk

Answer 2

The hormone prolactin is released from the anterior pituitary gland

Prolactin is produced in pregnancy but milk production is suppressed by oestrogen and progesterone (placental hormones)

Once the placenta is birthed, and oestrogen and progesterone drop, the prolactin activates milk production in the acini cells.

Prolactin levels are higher at night time

Prolactin is also released when the baby suckles

Reduced oestrogen —> progesterone —> prolactin effect starts —> milk production increased

Question 3

Sum up the process of prolactin ordering milk

Answer 3

1. Baby suckles
2. Nerve impulse from the sensory nerves in the nipple
3. The impulse is sent to the hypothalamus then to the anterior pituitary gland stimulated, releasing prolactin
4. Hormones (prolactin) are in the blood stream.
5. Both breasts receive messages to make milk