Lactation

LACTATION

Q. 1

Initiation of lactation is affected by :

 A

Progesterone

 B

Prolactin

 C

HPL

 D

All

Q. 1

Initiation of lactation is affected by :

 A

Progesterone

 B

Prolactin

 C

HPL

 D

All

Ans. D

Explanation:

Ans is a, b and c Prolactin; HPL; and Progesterone

Lactation can be divided into 3 stages :

Stage I : Mammogenesis – Mammary growth and development

Hormones responsible :

Growth                        Main hormone                                          Supporting hormones

Ductal growth             Oestrogen                                        Growth hormone and glucocorticoids

Alveolar growth          Progesterone                                   Prolactin, prednisolone and other

(in the oestrogen primed breast)                                       growth promoting factors

Stage ii :                 Lactogenesis : Initiation of milk secretion

Main hormone responsible : Prolactin

Although prolactin levels continue to rise as pregnancy advances, placental sex steroids block prolactin induced secretory activity of-the glandular epithelium. Therefore, lactation is not initiated until plasma estrogens progesterone, and human placental lactogen (hPL) level fall after delivery.”

Supporting hormones : • Estrogens

  • Progestins
  • Human placental Lactogen

Stage

Galactopoiesis or Maintenance of established milk secretion is mainly by suckling°. Hormones responsible :

  • Prolactin°                                   • Oxytocin°
  • Growth hormone°                       • Thyroxine/Parathyroid hormone°
  • Cortisol°                                     • Insulin°

Q. 2

Strongest stimulus of lactation is by :

 A

Metoclopramide

 B

Post partum hemorrhage

 C

Bromocripti ne

 D

Suckling

Q. 2

Strongest stimulus of lactation is by :

 A

Metoclopramide

 B

Post partum hemorrhage

 C

Bromocripti ne

 D

Suckling

Ans. D

Explanation:

Suckling


Q. 3

Galactokinesis means :

 A

Sustaining lactation

 B

Secretion of milk

 C

Ejection of milk

 D

Synthesis of milk

Q. 3

Galactokinesis means :

 A

Sustaining lactation

 B

Secretion of milk

 C

Ejection of milk

 D

Synthesis of milk

Ans. C

Explanation:

Ejection of milk


Q. 4

Which among the following is a function of prolactin during lactation?

 A

Increased FSH

 B

Increased libido

 C

Increased testosterone

 D

Decreased estrogen

Q. 4

Which among the following is a function of prolactin during lactation?

 A

Increased FSH

 B

Increased libido

 C

Increased testosterone

 D

Decreased estrogen

Ans. D

Explanation:

Prolactin (PRL) acts to induce and maintain lactation, decrease reproductive function, and suppress sexual drive.
PRL inhibits reproductive function by suppressing hypothalamic GnRH and pituitary gonadotropin secretion and by impairing gonadal steroidogenesis in both women and men.
In the ovary, PRL blocks folliculogenesis and inhibits granulosa cell aromatase activity, leading to hypoestrogenism and anovulation. PRL also has a luteolytic effect, generating a shortened, or inadequate, luteal phase of the menstrual cycle. In men, attenuated LH secretion leads to low testosterone levels and decreased spermatogenesis.
These hormonal changes decrease libido and reduce fertility in patients with hyperprolactinemia.
 
Ref: Melmed S., Jameson J.L. (2012). Chapter 339. Disorders of the Anterior Pituitary and Hypothalamus. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison’s Principles of Internal Medicine, 18e.

Q. 5

Which of the following statement regarding Prolactin levels is TRUE?

 A

Lowest in pregnancy and increases after delivery

 B

Highest during pregnancy and fall during lactation

 C

Unaffected by pregnancy and lactation

 D

Variable in every pregnancy

Q. 5

Which of the following statement regarding Prolactin levels is TRUE?

 A

Lowest in pregnancy and increases after delivery

 B

Highest during pregnancy and fall during lactation

 C

Unaffected by pregnancy and lactation

 D

Variable in every pregnancy

Ans. B

Explanation:

Maternal plasma levels of prolactin increase markedly during normal pregnancy and concentrations are usually 10-fold greater at term—about 150 ng/mL—compared with nonpregnant women. Paradoxically, plasma concentrations decrease after delivery even in women who are breast feeding.

During early lactation, there are pulsatile bursts of prolactin secretion in response to suckling. 

Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y. (2010). Chapter 5. Maternal Physiology. In F.G. Cunningham, K.J. Leveno, S.L. Bloom, J.C. Hauth, D.J. Rouse, C.Y. Spong (Eds), Williams Obstetrics, 23e. 

Q. 6

The breast becomes fully differentiated during pregnancy and lactation. All the following statements are true regarding the pregnant and lactating breast, EXCEPT:

 A

The terminal lobular units are most affected during pregnancy

 B

Cuboidal luminal epithelial cells show vacuolization

 C

Fat droplets occur in the cytoplasm of the epithelium

 D

There is an increase in the interlobular connective tissue

Q. 6

The breast becomes fully differentiated during pregnancy and lactation. All the following statements are true regarding the pregnant and lactating breast, EXCEPT:

 A

The terminal lobular units are most affected during pregnancy

 B

Cuboidal luminal epithelial cells show vacuolization

 C

Fat droplets occur in the cytoplasm of the epithelium

 D

There is an increase in the interlobular connective tissue

Ans. D

Explanation:

The breast becomes fully differentiated during pregnancy and lactation. The terminal lobular units are most affected during this physiologic state.

Several histologic changes occur in the terminal ducts and lobules with enlargement and formation of new lobular units early in pregnancy.

By the end of the second trimester secretory changes are well developed and the cuboidal luminal epithelial cells show evidence of vacuolization.

Accumulation of fat droplets occurs within the cytoplasm of the epithelium of the lobules during the third trimester.

The lobules undergo striking hyperplasia to occupy most of the breast parenchyma during this time, with a decrease in the interlobular connective tissue.

At term the expanded lobular units show marked distention of their lumina by colostrum.
 
Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y. (2010). Chapter 5. Maternal Physiology. In F.G. Cunningham, K.J. Leveno, S.L. Bloom, J.C. Hauth, D.J. Rouse, C.Y. Spong (Eds), Williams Obstetrics, 23e.


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