Mammary gland

Question 1

dairy cow

Answer 1

primary foster mom of human race

Question 2

lactation

Answer 2

4 stages- mammogenesis, pact-genesis, galactopoiesis, involution
main process= supply offspring

Question 3

mammogenesis

Answer 3

development of mammary gland

Question 4

lactogenesis

Answer 4

production of milk

1st produce then secrete

Question 5

galactopoiesis

Answer 5

secretion and continued production of milk

Question 6

involution

Answer 6

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

Question 7

mammary gland anatomy

Answer 7

embryology- modified sweat gland, mammary ridges, primary and secondary buds

Question 8

canalization (mature mammary gland)

Answer 8

lactiferous ducts

where milk will flow out of glands

myoepithelial cells

goes through mammary ridge before primary mammary bud, then secondary mammary bud and lastly canalization

Question 9

monotremes

Answer 9

sweat milk

ex: platypus and porcupine

Question 10

mammary gland internal anatomy

Answer 10

teat sphincter= keep teat closed

gland cistern feeds into lobe and lobules
lobes contain alveoli

alveolus has a specialized secretory epithelial cell
myoepithelial cell squeeze and eject milk
milk let down via oxytocin

Question 11

alveoli

Answer 11

functional structure

milk produced and drained through lactiferous ducts

Question 12

mammogenesis- puberty

Answer 12

development of mammary gland
further duct and alveolar development- allometric growth (increased rate)
progesterone stimulates alveoli growth
estrogen stimulates duct system growth
growth hormone also contributes to MG development

Question 13

allometric

Answer 13

something growing faster than rest of body

increased rate, different than isometric

Question 14

hormonal influence on mammary gland growth

Answer 14

E2, P4 and GH

stromal tissue= lower in mass and has a steady increase as move towards 2nd pregnancy and lactation

ductal tissue has a greater mass than stromal tissue- ductal tissue increases in mass at each pregnancy

secretory tissue has the greatest mass and increases great at each sequential pregnancy/lactation

Question 15

pregnancy- development of mammary gland

Answer 15

terminal alveoli develop under influence of prolactin, adrenal corticosteroids, and placental lactogen

lactogenesis- production of milk, is triggered by a decrease in progesterone and increase in prolactin

Question 16

hormones at beginning of first pregnancy

Answer 16

high prolactin, PL, steroids

Question 17

hormones at beginning of first lactation

Answer 17

low P4, high prolactin, at parturition

Question 18

cow mammary glands

Answer 18

inguinal
4 teats
1 canal per teat

Question 19

mare, goat and sheep mammary glands

Answer 19

inguinal, 2 teats

horse- 2 to 3 ducts per teat

Question 20

dog mammary glands

Answer 20

(thoraco)abdominalinguinal
10 (8-12)
5-6 ducts per teat

Question 21

pig mammary glands

Answer 21

thoracoabdominoinguinal 
14 (10-18)

Question 22

primates and elephants

Answer 22

thoracic
4 teats
primates- 8 to 10 ducts per teat

Question 23

supernumerary teats

Answer 23

can be problem in cows

Question 24

lactogenesis process

Answer 24

milk synthesis

milk produced by specialized epithelial cells and secreted into the lumen of alveolus

Question 25

cellular mechanisms for milk synthesis and secretion

Answer 25

milk fat globule (contains ~3.5%) secretory vesicle attached to cell membrane proteins and immunoglobulins secreted across the cell plasma cell= B cell, WBC

Question 26

milk synthesis- lactogenesis

Answer 26

1. exocytosis 2. lipid 3. apical transport 4. transcytosis 5. paracellular

Question 27

exocytosis process

Answer 27

most components of the aqueous phase (Casein and lactose) are secreted casein- produced in the RER, transferred to golgi and packed in SV lactose- produced in golgi from glucose and galactose, packaged into SV

Question 28

lipid process

Answer 28

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

Question 29

apical transport process

Answer 29

water and electrolytes (Ca, Na, Cl, K)

Question 30

transcytosis process

Answer 30

available during lactation in a healthy MG allows transport of secretory IgA from the interstitial space (produced by plasma cells or from blood) into milk other proteins, hormones and Growth factors (IGF-1) are believed to be transported this way

Question 31

Paracellular process

Answer 31

allow transport of other IGs and leukocytes in late gestation and infection (mastitis) products of the dissolution of the mammary cells during involution can also be cleared using this pathway

Question 32

mammary gland function

Answer 32

plays key role in allowing fetus to survive outside the uterus ab transfer (colostrum); transplacental transfer occurs in primates but not in domestic animals nutrition (milk) cow, sheep, goat and mare rely on passive transport

Question 33

colostrum

Answer 33

first milk from dam provides passive transfer IgG protection against pathogens in the first month of life neonatal immune system not mature

Question 34

degree of innovation of placenta

Answer 34

epitheliochorial and endotheliochorial are in direct contact with chorion haemochorial- maternal blood vessels infiltrate

Question 35

type of placentation and passive transfer

Answer 35

horse, pig and camelid- epitheliochorial- 100% colostrum, no prepartum immunoglobulins cow, sheep/goat - synepitheliochorial - 100% colostrum, no prepartum Immunoglobulins dog/cat- endotheliochorial - 5 to 10% prepartum transfer, 90 to 95% colostrum immunoglobulin transfer primate- hemochorial- 90% prepartum immunoglobulin transfer, only 10% colostral transfer

Question 36

colostrum

Answer 36

factors affecting colostrum quality: age of dam (older better) number of lactations (linked to age) vaccination status (vaccines help) health status of dam (healthy is better) volume of colostrum (less is better)- dilution affect

Question 37

failure of passive transfer

Answer 37

inadequate supply from dam- premature lactation (prepartum milking or suckling by calves), poor health/vaccination status failure to suckle- delay to nurse, inability to nurse (birth defects, dystocia, prolonged parturition-hypoxia) failure to absorb into bloodstream- GI colonization by microbes closure of villous epithelium (24 h after birth)

Question 38

Nutrition

Answer 38

composition of milks at mid-lactation cat= highest fat in milk and high dry matter- milk more concentrated

Question 39

Galactopoiesis- secretion and continued production of milk

Answer 39

prolactin and GH stimulate galactopoiesis suckling stimulates oxytocin release- myoepithelial cell contraction, milk let down

Question 40

oxytocin

Answer 40

produced from posterior pituitary from tonic center affects lobe and lobules- myoepithelial cell produced milk suckling stimulates milk let down due to oxytocin

Question 41

blockage of milk letdown

Answer 41

block oxytocin release- unusual stimuli or pain message goes to brain to the pituitary gland and then to the heart (adrenaline from nerve endings overcomes letdown hormone action)

Question 42

galactopoiesis process

Answer 42

removal of milk from mammary gland stimulates milk production less pressure and less feedback inhibitor of lactation (FIL) which inhibits milk production higher frequency of milk removal then the higher the production allowing mammary gland to reach storage capacity decreases rate of milk synthesis, pressure atrophy if produce more inhibits production until removed and then inhibition removed

Question 43

lactation peaks

Answer 43

3-8 weeks following onset (species variations) then declines steadily ``` bitch= 3-4 wks sow= 3 wks cow= 4-8 wks mare= 4-8 wks ```

Question 44

involution

Answer 44

gradual regression of mammary gland following lactation decrease in prolactin and growth hormone- signals apoptosis of epithelial cells cessation of suckling or milking- decreases stimuli for production; increased pressure and pressure atrophy