induces ductal growth and epithelial cells [secretion of growth factors from stromal cells]
What role does progesterone play in mammogenesis?
stimulation of ductal side branching and formation of alveolar buds
Estradiol stimulates ________ receptors at the mammary gland.
What role does growth hormone play in mammogenesis?
stimulates glandular growth during all stages of development; stimulates IGF-1
What role does placental lactogen play in mammogenesis?
synergizes with estradiol, progesterone, prolactin, and GH
How does parturiation affect the hormones involves with lactation?
increases prolactin, glucocorticoids, GH, and estradiol; decreases the negative influence of progesterone (in the cow to allow her to begin lactating)
Simultaneous increase in __(2)__ concs are required for final mammary growth.
estradiol and progesterone
The removal of __________ at parturition initiates lactation.
There are no ________ receptors in the mature mammary gland; therefore, after lactation has been initiated, administration of ________ had no effect on milk yield.
progesterone; exogenous progesterone
Hormone responsible for the onset and establishment of lactation; receptors are increased in the mammary near parturition.
Prolactin has a key role in ___________ but a lesser role in ___________.
What are the effects of a reduced basal prolactin?
reduced milk production
What role do glucocorticoids play in lactogenesis and galactopoiesis? (2)
differentiation of alveolar secretory cells during lactogenesis; support homeostasis
Lactating cows double the amount of _________ in the mammary cells when compared to non-lactating cows.
What role does oxytocin play in lactogenesis and galactopoiesis? (2)
milk let down, milk production throughout lactation
What role does insulin play in lactogenesis and galactopoiesis? (1)
What role do the thyroid hormones play in lactogenesis and galactopoiesis? (2)
maintenance of lactation, support homeostasis
What role does GH play in lactogenesis and galactopoiesis? (2)
galactopoietic hormone, promotes flux of nutrients and energy in mammary
How does BST administration increase milk secretion? (2)
directly and indirectly stimulates mammary tissue, effects other tissues to supply nutrients to support milk production
What effects do lactogenesis and galactopoiesis have in body tissues? (2)
decrease glucose uptake, decrease oxidation of AAs for energy
What effects do lactogenesis and galactopoiesis have in the liver? (1)
What effects do lactogenesis and galactopoiesis have in fat stores? (4)
decreased uptake of glucose, decreased lipogenesis, increase lipolysis, increased glucose from glycerol via lipolysis
Why is it essential to remove milk a frequent intervals? (4)
reduce intramammary pressure, increase blood flow, removes substances that inhibit milk production--> increased milk production
How long should the dry period be?
What is a consequence of extended dry periods?
>80 days has a negative effect on future milk production
During mammary gland involution, there is _________.
What histological changes associated with mammary gland involution? (4)
increased leukocytes and connective tissue, decreased intra-alveolar area and cytoplasmic organelles
Raw materials for milk production are obtained from ________.
5 mechanisms of secretion of milk contents.
milk fat pathway, golgi pathway, transcytosis, transporter channels, paracellular transport
Release of oxytocin from the _______ causes __________ [at the cellular level].
posterior pituitary; contraction of mammary myoepithelial cells
A mixture of lacteal secretions and blood serum constituents, that is accumulated in the mammary gland during the last weeks of pregnancy, and that is crucial for the transfer of passive immunity to the newborn.
Pre-partum transfer of Ig from maternal circulation into mammary gland secretion.
Colostrogenesis begins ___________ and stops __________.
4-6 weeks before parturition; abruptly after calving
Colostrogenesis is influenced by what hormones? (3)
estrogen, progesterone, prolactin
What are the 2 classes of mastitis pathogens?
contagious and environmental
What are the 3 most important contagious mastitis pathogens?
Strep ag, Staph aureus, Mycoplasma
What are the most important/common environmental mastitis pathogens? (8)