Lecture 19: Mammary gland and lactation (Galvao) Flashcards Preview

Undeleted > Lecture 19: Mammary gland and lactation (Galvao) > Flashcards

Flashcards in Lecture 19: Mammary gland and lactation (Galvao) Deck (48)
Loading flashcards...
0
Q

how does the mammary gland first develop in prenatallife?

A

as ridges of epidermis called mammary ridges

1
Q

the mammary gland is a modified version of what gland?

A

sweat gland

2
Q

In what order do mammary glands first develop?

A

primary mammary buds develop from mammary ridges, with branching and lengthening of the secondary buds and finally canalization (duct formation) occurring prior to birth.

3
Q

what portion of mammary gland development occurs at puberty?

A

further duct and alveolar development - allmoetric growth (increased rate)

4
Q

what is the influence of progesterone on mammary gland development?

A

it stimulates alveoli growth

5
Q

what influence does estrogen have on mammary gland growth?

A

duct system growth

6
Q

what influence does prolactin and growth hormone have on mammary gland development?

A

promote duct development

7
Q

when do final stages of mammary gland development occur?

A

pregnancy

8
Q

what influence do prolactin, adrenal corticosteroids and placental lactogen have on mammary gland development during pregnancy?

A

they develop terminal alveoli

9
Q

what stimulates lactogenesis (production of milk)

A

a decrease in progesterone and an increase in prolactin

10
Q

during pregnancy, terminal alveoli begin to grow into branches called…

A

lobules

11
Q

what type of cells produce milk? and where is it secreted?

A

specialized epithelial cells and secreted into the lumen of alveolus

12
Q

what are the 5 different ways of milk synthesis/secretion?

A
just remember the cow L-E-A-P-T over the moon:
L - lipid
E - exocytosis
A - apical transport
P - paracellular
T - transcytosis
13
Q

describe exocytosis

A

most components of the aqueous phase (casein and lactose) are secreted by exocytosis.
casein - produced in the rER,transferred to golgi, packaged into SV
lactose - produced in the golgi from glucose and galactose, packaged into SV

14
Q

describe milk synthesis: lipid

A

produced in the sER from FA and glycerol, coalesce into large droplets are enveloped by the plasma membrane and released as a fat globule.

15
Q

describe milk synthesis: apical transport

A

water, Na, Cl, K, bicarb, and monosaccharides can cross the apical membrane

16
Q

describe milk synthesis: transcytosis

A

allows transport of IgA from the interstitial space (produced by plasma cells or from blood) into milk.

17
Q

describe milk synthesis: paracellular

A

allow for transport of IGs and leukocytes in late gestation and infection (mastitis).

18
Q

number of teats in a cow and their location

A

4 - inguinal

19
Q

number of teats in the mare, goat, sheep and location

A

2 - inguinal

20
Q

number and location of teats in a dog

A

(thoraco)abdominoinuginal 10 ( 8 -12)

21
Q

number and location of teats in the pig

A

thoracoabdominoinguinal 14 (10 - 18)

22
Q

number and location of teats in primates and elephants

A

thoracic - 2

23
Q

supernumerary nipple - what is it and in what animal can it be a problem?

A

a supernumerary nipple is an additional nipple. can be a problem in cows.

24
Q

colostrum - define

A

first milk from mom. it provides passive transfer of immunoglobulins (IgG) and provides protection against pathogens in the first month of life.

25
Q

in what animal does antibody transplacental transfer occur and thus not need colostrum?

A

primates

26
Q

factors affecting colostrum quality include:

A

age of mom, number of lactations, vaccination status, health status, volume of colostrum (less is better)

27
Q

what 3 ways can cause failure of passive transfer?

A
  1. inadequate supply from dam
  2. failure to suckle
  3. failure to absorb into bloodstream
28
Q

why is it important for the neonate to begin drinking colostrum ASAP?

A

because efficiency of absorption is ~ 25% at birth but gut closure occurs in a linear fashion beginning at birth and is completely closed by 24 hours and the calf needs ~ 4L of good quality colostrum.

29
Q

what are the 4 stages of lactation?

A
  1. mammogenesis
  2. lactogenesis
  3. galactopoiesis
  4. involution
30
Q

define mammogenesis

A

development of mammary gland

31
Q

define lactogenesis

A

production of milk

32
Q

define galactopoiesis

A

secretion and continued production of milk

33
Q

define involution

A

atrophy of secretory cells induced by cessation of suckling and decreased prolactin and GH

34
Q

when does momogenesis occur?

A

during pregnancy
high estrogen promotes development of mammary ducts
high progesterone promotes lobulo-alveolar growth

35
Q

when does lactogenesis occur and what does it do?

A

during late gestation
progesterone falls and prolactin rises
this initiates milk synthesis

36
Q

what stimulates galactopoiesis and what does it do?

A

prolactinand growth hormone stimulate galactopoiesis.

suckling stimulates oxytocin release and contract myoepithelial cells to initiate “milk let-down”

37
Q

what stimulates milk production?

A
  • removal of milk from mammary gland

- the higher the frequency of milk removal the higher the production

38
Q

what overrides letdown hormone action?

A

adrenaline from nerve endings in response to unusual stimuli or pain

39
Q

what decreases the rate of milk syntehsis?

A

allowing mammary gland to reach storage capacity; pressure atrophy

40
Q

when does lactation peak?

A

3 - 8 weeks following its onset, then declines steadily

41
Q

when does lactation peak in the bitch?

A

3- 4 weeks

42
Q

when does lactation peak in the sow?

A

21 days

43
Q

when does lactation peak in the cow?

A

30 days - 60 days

44
Q

when does lactation peak in the mare?

A

30 - 60 days

same as the cow

45
Q

how high are energy demands for the lactating cow?

A

super high! they produce 100 lbs of milk/day!

total energy needed = 60Mcal/day - 4.6 times maintenance
super human athletes need 6 - 7 Mcal/day - 2.4-2.8 times maintenance

46
Q

define involution

A

the gradual regression of the mammary gland following lactation

47
Q

what stimulates involution?

A
  1. decrease in prolactin and growth hormone - causes apoptosis of epithelial cells
  2. cessation of suckling - decreases stimulus for production causes increase in pressure and eventually pressure atrophy

Decks in Undeleted Class (134):