Lactation

Lactation


LACTATION

  • Process of milk secretion.

Preparations:

  • Begins long before required.
  • Breast development takes place at puberty.
  • Further development occurs during pregnancy.

Phases of lactation:

  • Divided into four phases
  • Mammogenesis
  • Lactogenesis
  • Galactokinesis 
  • Galactopoiesis.

1. Mammogenesis:

  • Preparation of breasts.
  • Involves both duct growth & lubulo-alveolar (lobule & secretory alveoli) growth.

Hormones involved:

  • Estrogen – Proliferation & growth of mammary duct.
  • Glucocorticoids – To mobilize amino acids.
  • Growth hormone – To mobilize glucose.
  • Insulin & Prolactin – To promote protein synthesis.
  • Progesterone –  Development of lobuloalveolar system.

2. Lactogenesis:

  • Synthesis & secretion of milk from breast alveoli.
  • Hormone involved – Prolactin.

During pregnancy:

  • No milk secretion despite higher prolactin level.
  • Because estrogen & progesterone have direct inhibitory action on lactogenesis.

After parturition:

  • Sharp fall in estrogen & progesterone levels.
  • Inhibitory effect on lactogenesis removed & lactation occurs.

3. Galactokinesis/Milk ejection/Milk let-down:

  • Hormone involved – Oxytocin
  • Stimulates contraction of myoepithelial cells in mammary alveoli & lactiferous ducts.
  • Released on nipple stimulation during sucking.

4. Galactopoiesis:

  • Process of lactation maintenance.
  • Hormone involved – Prolactin.
Exam Question
 

LACTATION

  • Estrogen influences mammary duct proliferation & growth.
  • Progesterone influences lobuloalveolar system development.
  • Lactogenesis is milk synthesis & secretion from breast alveoli influenced by prolactin.
  • Galactokinesis influenced by Oxytocin.
  • Oxytocin stimulates myoepithelial cells contraction in mammary alveoli & lactiferous ducts.
  • Oxytocin is released on nipple stimulation during sucking.
  • Galactopoiesis is process of lactation maintainence influenced by prolactin.
Don’t Forget to Solve all the previous Year Question asked on Lactation

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