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ESA 4 - Reproductive System > Lactation > Flashcards

Flashcards in Lactation Deck (67):
1

Where are the mammary glands found?

Embedded in breasts

2

Where are the mammary glands found?

Embedded in breasts

3

What are the mammary glands made up of?

15-24 lobulated masses of tissue, with fibrous and adipose tissue, and blood vessels, in between

4

What are the lobes of the mammary glands made up of?

Alveoli
Blood vessels
Lactiferous ducts

5

What is found on the surface of the alveoli of the mammary glands?

Contractile machinery

6

Where are the lactiferous ducts of the mammary glands found?

Lining the alveoli

7

What do the sinuses/lacunae of the lactiferous ducts lead to?

The nipple pores

8

Are mammary tissue and breast tissue the same thing?

No

9

How does development of the mammary tissue begin?

In utero, with invagination of the epithelium which takes some melanin

10

Describe the mammary tissue at birth?

Only a few ducts present

11

What happens to the mammary tissue at puberty?

Ducts sprout and branch, and alveoli begin development

12

What happens to mammary tissue with each menstrual cycle?

Changes in breast tissue occur with changes in oestrogen and progesterone

13

What is the result of oestrogen increase in pregnancy on the mammary tissue?

Causes development of ducts and alveoli, and the connection of the myoepithelial cells

14

What are the physiological stages of lactation?

1. Preparation of breasts - mammogenesis
2. Synthesis and secretion from the breast alveoli - lactogenesis
3. Ejection of milk - galactokinesis
4. Maintenance of lactation - galactopoiesis

15

When does mammogenesis occur?

During pregnancy

16

What happens in mammogenesis?

Hypertrophy of ductular-lobular-alveolar system
Prominent lobules form
Alveolar cells differentiate

17

When are the breasts capable of milk production?

From the 2nd trimester

18

What happens to the milk thats produced by the breasts?

It is secreted into the lumen of alveolar ducts

19

What happens to the breast towards the end of pregnancy?

Nipple becomes erect
Areola enlarges and becomes darker
Montgomery tubercles form
Breast becomes more sensitive

20

What is the purpose of the arerola enlarging and becoming darker towards the end of pregnancy?

So baby can see them when feeding

21

How do montgomery tubercles form?

Fusion of sebaceous glands with mammary lobules

22

What is the purpose of Montgomery tubercles?

Produce sebum which lubricates the nipples and prevents them from cracking during feeding
Produce pheromones which helps baby determine where the nipple is

23

Why does the breast become more sensitive towards the end of pregnancy?

Due to production of sensory neurones under the influence of oestrogen

24

How much milk is secreted during pregnancy?

Little

25

Why is only a little milk secreted during pregnancy?

Because there is a high progesterone/oestrogen ratio in early gestation which favours growth, not secretion

26

What does a high progesterone/oestrogen ratio stimulate in the breast?

Proliferation and growth of adipose

27

What is the importance of the proliferation and growth of breast adipose in pregnancy?

It is the raw material for milk

28

How does a high progesterone/oestrogen ratio stop milk secretion?

It prevents the production of the prolactin receptor in the alveoli

29

Where does lactogenesis take place?

In the alveolar cells

30

Where is the fat for lactogenesis synthesised?

In the SER

31

How is the protein secreted in lactogenesis?

Via Golgi apparatus

32

What are the constituents of breast milk?

Fat
Protein
Sugars
Neutrophils
Macrophages

33

How do neutrophils and macrophages get into the breast milk?

Can enter the alveolar space (lumen)

34

What is the purpose of the neutrophils and macrophages in the breast milk?

Protect against bacterial infection

35

What is produced soon after birth (0-3 days)?

40ml/day of colostrum

36

How does colostrum differ from breast milk produced later?

Less water, fat, and sugar
More protein, particularly immunoglobulins (IgA, IgM, IgG)
Contains white cells

37

How many grams of immunoglobulins are there in colostrum?

19g

38

What is the purpose of the immunoglobulins in colostrum?

Coat intestinal mucosa preventing bacteria from entering intestinal cells

39

Why can't you give a newborn cows milk?

Contains a lot of the protein casein, which the neonate can't digest, and so gives colic, GI proteins, and watery diarrhoea

40

What happens to the breast milk over the first two weeks?

Composition gradually changes to mature milk

41

What is the composition of 'intermediate milk'?

90% water
7% sugar (lactos)
3% fat
Proteins
Minerals and vitamins
Endocannabinoids

42

What proteins are found in the intermediate milk?

Lactalbumin
Lactoglobulin
Lacotoferrin

43

What is the purpose of the endocannabinoids in breast milk?

Binds to cannaboid receptors, causing the baby to feel full, and so stop suckling, and feel sleepy

44

What stimulates breast tissue growth?

High progesterone and oestrogen in pregnancy

45

What allows secretion of breast milk?

Fall in steroids

46

What promotes milk secretion?

Prolactin

47

What is prolactin?

Polypeptide hormone

48

What secretes prolactin?

Anterior pituitary gland

49

What is prolactin secretion controlled by?

Dopamine from hypothalamus (inhibits)

50

How do factors promoting secretion of prolactin exert their effects?

They reduce dopamine secretion

51

What factors increase prolactin?

TRH
Oestrogen

52

How does oestrogen cause the secretion of prolactin?

It causes lactotroph hyperplasia, which means there are more cells producing prolactin

53

When is TRH produced?

When baby suckling

54

Other than the anterior pituitary, where else is prolactin produced?

Decidua

55

What does deciudal prolactin stimulate?

Colostrum

56

Is decidual prolactin inhibited by dopamine?

No

57

What is pituitary prolactin secretion promoted by?

Suckling - potent neuroendocrine reflex

58

What does suckling at one feed do?

Promotes prolactin release, which causes production of the next feed, which accumulates in alveoli and ducts

59

What is required to maintain milk production?

Sufficient suckling stimulus at each feed

60

What happens if there is no suckling?

Milk production ceasses gradually, and there is turgor induced damage to secretory cells

61

How can milk production be maintained by suckling?

Free feeding 1-3 hours apart/day

62

How do babies get the milk from the breast?

They do not suck milk about of the breast, it is ejected by a 'let down' reflex

63

How does the let down reflex work?

Baby suckling stimulates receptors on nipples, signal to hypothalamus causes oxytocin, which leads to milk ejection

64

How does oxytocin lead to milk ejection?

Myoepithelial cells surround the alveoli, and are contracted by oxytocin to squeeze milk out of the breast

65

Where is oxytocin release from?

Posterior pituitary

66

How does galatopoeisis occur?

Oxytocin release is a neuro-endocrine reflex from suckling/expressing systems

67

What stimulates the oxytocin neuro-endocrine reflex?

Anticipation of feed
Fondling the baby