Anatomy of the Breasts and Physiology of Lactation Flashcards
Describe the external structure of the breast
- Situated one on each side of the midline on the anterior chest wall
- Extend from the second to the sixth rib
- Lie over the pectoralis major muscle
- Supported by connective tissue
- Hemispherical in shape- axillary tail
What is the areola?
Pigmented area surrounding the nipple
What are the alveoli?
Minute sacs of milk secreting cells around a lumen
Which hormone stimulates alveoli to produce milk and where is it released from?
Prolactin which is released from the Anterior Pituitary Gland
How quickly do prolactin levels rise?
Within 10 minutes of suckling
What is an acini cell?
A milk-secreting cell
What causes the prolactin receptor sites to open on the acini cells?
The expulsion of the placenta following birth
How and where is oxytocin secreted?
When the baby suckles, a sensory impulse triggers the Posterior Pituitary Gland to secrete oxytocin
What effect does oxytocin have on the breast?
It stimulates the myoepithelial cells to contract.
This propels the milk along the ducts to the lactiferous sinuses (ampulla)
What can hinder the secretion of oxytocin?
Anxiety, stress and pain
What are positive signs of breast feeding?
Squeezing / tingling in her breasts
Milk leaking
Pain from uterine contractions
Slow deep sucks and swallowing
What effect does the feedback inhibitor have on lactation?
Breast milk contains a protein which can reduce or inhibit milk production. If the breast contains a lot of milk then the inhibitor acts by slowing down milk production.
Frequent sucking reduces the level of the inhibitor.
Describe the ENDOCRINE control of lactation
Controlled by pituitary gland using oxytocin and prolactin
It is systemic (both breasts)
Describe the AUTOCRINE control of lactation
Controlled by feedback inhibitor of laction
A build up slows milk production
A removal of the protein stimulates production
Is it local (one breast)
