Oxytocin and Prolactin Flashcards

Flashcards about the roles of oxytocin and prolactin.

What are the two hormones primarily involved in milk production and release during nursing?

Oxytocin and prolactin

What is the function of prolactin?

It stimulates the production of milk.

What is the function of oxytocin?

It makes the smooth muscle cells around the glands in the breasts contract to release milk and helps the uterus contract during labor.

Where are oxytocin and prolactin synthesized?

In the brain, by the hypothalamus and the pituitary gland.

Which nuclei in the hypothalamus secrete oxytocin?

The paraventricular and supraoptic nuclei

What other hormone is secreted by the paraventricular and supraoptic nuclei, besides oxytocin?

Vasopressin, also known as antidiuretic hormone

What are Herring bodies?

Small dilations along the axons of neurons that store oxytocin until it is released into the blood.

How do oxytocin levels change outside of pregnancy?

Oxytocin levels are low, but production increases slightly during orgasm.

What cells synthesize prolactin?

Lactotrophs in the anterior lobe of the pituitary gland

How is prolactin production typically controlled in non-pregnant, non-breastfeeding women and in men?

Through dopamine secretion by the hypothalamus (prolactin inhibiting factor) and thyrotropin releasing hormone (prolactin releasing hormone).

What is the function of dopamine in prolactin regulation?

It binds to receptors on lactotrophs and inhibits the release of prolactin.

What two hormones stimulate the growth of milk-producing alveoli during pregnancy?

Oxytocin and prolactin, along with estrogen and progesterone

What inhibits milk production during pregnancy?

High levels of estrogen and progesterone

What signals the hypothalamus to produce more oxytocin?

Dilation of the cervix

How does oxytocin affect the cervix?

It dilates the cervix more, allowing the baby to pass through.

What happens to estrogen and progesterone levels after the placenta detaches?

Estrogen and progesterone levels drop.

What effect does breastfeeding have on prolactin levels?

Breastfeeding increases prolactin levels, which in turn increases milk production.

What is the effect of high prolactin levels on gonadotropin releasing hormone (GnRH)?

High prolactin levels inhibit the release of GnRH from the hypothalamus.

How is milk ejected from the breasts during breastfeeding?

Tactile receptors in the nipple send a signal to the hypothalamus, which produces oxytocin in pulses activating the myoepithelial cells.

What is the role of oxytocin after childbirth?

Oxytocin makes the muscle cells contract and push the milk out of the breasts during breastfeeding.

Where is oxytocin produced and released?

Produced by the hypothalamus and released by the posterior pituitary gland.

Where is prolactin produced?

Produced by the anterior pituitary gland.