Lecture 10 - The breast Flashcards

1
Q

what are the breasts aka?

A

mammary glands

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2
Q

where and what from are the breasts formed?

A

start forming in the embryo from modified sweat glands

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3
Q

the mammary glands are derived from tissue that is first identified in the _______ _____ that arise between the ________ (______) and the ______

A

mammary crests, axilla (armpit), groin

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4
Q

abnormal breast development happens where?

A

along the lines of the mammary crests

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5
Q

when does breast development start?

A

begins with the formation of the mammary buds at about 6 weeks

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6
Q

describe the first development of the breast

A

it takes place as a down growth of the epidermis to form the primary breast bud

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7
Q

how do the secondary breast buds form?

A

form by branching off the primary breast bud

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8
Q

as gestation progresses, the buds develop what?

A

lumens, e.g the buds become canalised

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9
Q

what induces canalisation of the secondary breast buds?

A

placental steroids (oestrogen and progesterone)

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10
Q

how many lactiferous ducts are present at the time of birth?

A

around 15-20 per breast

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11
Q

true or false, by birth the breasts are fully developed and could potentially make milk

A

true, but there is no hormonal stimulus

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12
Q

what is witch’s milk?

A

the colostrum-like milk produced by a newborn due to the fetus being exposed to placental steroids and maternal hormones at birth

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13
Q

true or false, the internal breast structure is the same in males and females

A

true

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14
Q

what are the three external structures of the breast

A

body of the breast
nipple
areola

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15
Q

describe the nipple

A

a raised, usually cylindircal pigmented structure
where the lacterferous ducts join the skin at the nipple

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16
Q

describe the areola

A

pigmented circle of tissue surrounding the nipple
contains sebaceous glands which give a granular texture to the areola

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17
Q

what are the internal structures of the breast?

A

adipose tissue of the pectoral fat pad
ligaments of cooper

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18
Q

describe the pectoral fat pad

A

determines the shape and size of the breast
gives the texture
makes up most of the breast tissue

19
Q

describe coopers ligaments

A
  • support the breasts
  • become less supportive with age and hormones in pregnancy
20
Q

each breast contains ________ lobes, each made up of milk-secreting _______.

A

15-20, lobules

21
Q

each of the lobules connects to a single __________ ____

A

lactiferous duct

22
Q

what is the lactiferous sinus?

A

an expansion of the lactiferous duct that opens onto the nipple to allow extraction of milk

23
Q

when do aveoli develop in the breast?

A

only after puberty and under the influence of oestrogen

24
Q

how much of the breast tissue is alveoli?

A

a small amount in comparison to the fat and duct system

25
Q

why do humans develop major mammary glands before pregnancy and most other animals dont?

A

due to the menstrual cycle and oestrogen and progesterone promoting the growth of alveolar buds, where sucessive cycles cause increased growth

26
Q

what are the noticeable premenstrual changes in the breast?

A

increase in volume of the breast and tenderness

27
Q

which component of the breast grows the most during pregnancy?

A

alveolar tissue

28
Q

ostrogen is essential for?

A

breast growth

29
Q

progesterone induces?

A

side branching of ducts

30
Q

prolactin is necessary for?

A

areolar development, but also stimulates casein and alpha-lactalbumin production for breast milk

31
Q

what do insulin and cortisol do in the breast?

A

stimulate alveolar epithelial cell division to develop glandular tissue

32
Q

what is the main noticeable difference between a lactating and resting breast under histology?

A

lactating will have lots of alveoli compared to resting

33
Q

describe breast size at pregnancy and lactation

A

2-3x near term pregnancy
3-4x lactating

34
Q

what hormone allows lactation not to happen until after birth?

A

progesterone (and oestrogen) prevents milk production
it also relaxes smooth muscle to prevent milk ajection

35
Q

what hormone is released by the anterior pituitary in response to a baby’s suckling?

36
Q

which reflex can cutting the nerves to the nipple prevent?

A

the neuroendocrine reflex of baby suckling causing prolactin release

37
Q

describe the milk production response

A

more suckling induces more prolactin secretion and leads to more milk, so the baby decides how much milk it needs

38
Q

what is the milk ejection response?

A

happens in response to oxytocin release by the posterior pituitary, and induces the contraction of the myoepithelial cells of the alveoli, causing ejection of the milk into the ducts

39
Q

what can cause the MER?

A

stimulation of female reproductive tract (sex)
environmental stimuli such as crying baby or baby smell

40
Q

what other hormones does prolaction suppress the secretion of?

A

FSH and LH, mostly LH
- and so lactating women have either irregular or no menstrual cycles - contraceptive effect

41
Q

benefits of breastfeeding to mother?

A

less cancer risk
lactation is protective against development of breast cancer

42
Q

benefits to the infant of breastfeeding?

A

protection from GI infection
less obesity
protective against diabetes and SIDS

43
Q

bottle fed babies are often ________, while breastfeed babies are often _______.

A

overweight, healthy weight

44
Q

what are supernumerary nipples/breasts?

A

additional breasts or nipples, usually occur along the line of the embryonic milk ridge. additional lactiferous ducts can also happen (may want to add)