Lecture 10 - The breast

Question 1

what are the breasts aka?

Answer 1

mammary glands

Question 2

where and what from are the breasts formed?

Answer 2

start forming in the embryo from modified sweat glands

Question 3

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

Answer 3

mammary crests, axilla (armpit), groin

Question 4

abnormal breast development happens where?

Answer 4

along the lines of the mammary crests

Question 5

when does breast development start?

Answer 5

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

Question 6

describe the first development of the breast

Answer 6

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

Question 7

how do the secondary breast buds form?

Answer 7

form by branching off the primary breast bud

Question 8

as gestation progresses, the buds develop what?

Answer 8

lumens, e.g the buds become canalised

Question 9

what induces canalisation of the secondary breast buds?

Answer 9

placental steroids (oestrogen and progesterone)

Question 10

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

Answer 10

around 15-20 per breast

Question 11

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

Answer 11

true, but there is no hormonal stimulus

Question 12

what is witch’s milk?

Answer 12

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

Question 13

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

Answer 13

true

Question 14

what are the three external structures of the breast

Answer 14

body of the breast
nipple
areola

Question 15

describe the nipple

Answer 15

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

Question 16

describe the areola

Answer 16

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

Question 17

what are the internal structures of the breast?

Answer 17

adipose tissue of the pectoral fat pad
ligaments of cooper

Question 18

describe the pectoral fat pad

Answer 18

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

Question 19

describe coopers ligaments

Answer 19

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

Question 20

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

Answer 20

15-20, lobules

Question 21

each of the lobules connects to a single __________ ____

Answer 21

lactiferous duct

Question 22

what is the lactiferous sinus?

Answer 22

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

Question 23

when do aveoli develop in the breast?

Answer 23

only after puberty and under the influence of oestrogen

Question 24

how much of the breast tissue is alveoli?

Answer 24

a small amount in comparison to the fat and duct system

Question 25

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

Answer 25

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

Question 26

what are the noticeable premenstrual changes in the breast?

Answer 26

increase in volume of the breast and tenderness

Question 27

which component of the breast grows the most during pregnancy?

Answer 27

alveolar tissue

Question 28

ostrogen is essential for?

Answer 28

breast growth

Question 29

progesterone induces?

Answer 29

side branching of ducts

Question 30

prolactin is necessary for?

Answer 30

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

Question 31

what do insulin and cortisol do in the breast?

Answer 31

stimulate alveolar epithelial cell division to develop glandular tissue

Question 32

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

Answer 32

lactating will have lots of alveoli compared to resting

Question 33

describe breast size at pregnancy and lactation

Answer 33

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

Question 34

what hormone allows lactation not to happen until after birth?

Answer 34

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

Question 35

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

Answer 35

prolactin

Question 36

which reflex can cutting the nerves to the nipple prevent?

Answer 36

the neuroendocrine reflex of baby suckling causing prolactin secretion

Question 37

describe the milk production response

Answer 37

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

Question 38

what is the milk ejection response?

Answer 38

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

Question 39

what can cause the MER?

Answer 39

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

Question 40

what other hormones does prolaction suppress the secretion of?

Answer 40

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

Question 41

benefits of breastfeeding to mother?

Answer 41

less cancer risk lactation is protective against development of breast cancer

Question 42

benefits to the infant of breastfeeding?

Answer 42

protection from GI infection less obesity protective against diabetes and SIDS

Question 43

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

Answer 43

overweight, healthy weight

Question 44

what are supernumerary nipples/breasts?

Answer 44

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