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ESA 4 - The Reproductive System > Lactation > Flashcards

Flashcards in Lactation Deck (13)
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1
Q

Describe the mammary glands

A
Embedded in breasts
15-20 lobulated masses of tissue
- Fibrous and adipose tissue in between
Lobes
- Alveoli
- Surrounded by blood vessels
- Lactiferous ducts (carry the secretions away)
2
Q

Describe the development of the mammary glands.

A

At birth only a few ducts present
At puberty
- Ducts sprout and branch
- Alveoli begin development

With each menstrual cycle
- Changes in breast tissue with changes in oestrogen &
progesterone (a cyclic growth pattern)

3
Q

Describe the development of the mammary glands during pregnancy.

A

Substantial further development
- Hypertrophy of ductular-lobular-alveolar system
- Prominent lobules form
- Alveolar cells differentiate to be capable of milk
production from mid gestation

4
Q

Tell me about the mammary glands during pregnancy.

A

Little milk secreted
High progesterone/oestrogen ratio
Favours growth but not secretion.

5
Q

Tell me about the mammary gland soon after birth.

A

It produces about 40ml per day of colostrum

  • Less water, fat & sugar than milk produced later
  • More protein, particularly immunoglobulins
6
Q

What happens to the colostrum from mammary glands over the 2 weeks after birth?

A

Composition gradually changes to ‘mature milk’

  • 90% water
  • 7% sugar (lactose)
  • 2% fat
  • Proteins (lactalbumin, lactoglobulin)
  • Minerals & vitamins
  • Energy value 27Mj.l/-1
  • ‘Sweet and semi-skimmed’ compared to cows milk
7
Q

Describe the synthesis of breast milk.

A

In alveolar cells

  • Fat in smooth endoplasmic reticulum
  • Protein secreted via Golgi apparatus
  • Sugar synthesised and secreted
8
Q

How is milk secretion controlled in mammary glands?

A

High progesterone oestrogen in pregnancy stimulates growth
Secretion allowed by fall in steroids
Promoted by prolactin

9
Q

What is prolactin?

A

Polypeptide hormone
Secreted by anterior pituitary gland
Controlled by dopamine from hypothalamus (inhibits)
Factors promoting secretion of prolactin reduce dopamine secretion (suckling)

10
Q

How is prolactin secretion promoted?

A
Promoted by suckling
Neuro-endocrine reflex
Suckling at one feed promotes prolactin which causes production of next feed
Which accumulates in alveoli and ducts
- Leads to turgor of the breasts
11
Q

What is the key to maintaining milk production?

A

Sufficient suckling stimulus at each feed

Milk production ceases gradually if no suckling - turgor induced damage to secretory cells (compressed blood vessels

12
Q

What is meant by milk let down?

A

Babies do not suck milk out of the breast
It is ejected by a let-down reflex

Myoepithelial cells surround alveoli
Contracted by oxytocin
To squeeze milk out of the breast
Oxytocin released from posterior pituitary

Oxytocin release a neuro-endocrine reflex
From suckling
- Anticipation of feed

13
Q

Is breast feeding good?

A

Yes
Babies fewer infections
Bonding
Encouragement needed to persist