mammary physiology quiz 2 Flashcards
Which of the following would most reduce persistency?
a. Fostering a newborn on another dam
b. Missing one milking in a dairy herd milked 3 times per day
c. Late pregnancy (7 months) in a dairy cow
d. Providing a dry or nonlactating period between lactations
e. All of the above would be equivalent
c.
Increased frequency of milking or suckling
a. Reduces metabolic activity of mammary epithelial cells
b. Stimulates daily milk yield
c. Stimulates mammary epithelial cell loss
d. Stimulates the involutionary process
e. All of the above
b.
Exogenous growth hormone would increase milk yield in cows only if
a. given during the first lactation of a dairy cow’s life
b. a dairy cow is in “positive energy balance”, or has sufficient nutrients available to support increased milk production
c. given during the first week of a cow’s lactation
d. it was given as an oral protein in her feed
b.
Milk yield is equal in two cows through day 30 of lactation. Beginning on day 31, cow A is injected daily with a high dose of cortisol and cow B is not treated. One week later….
a. Compared to cow B, milk yield would decrease in cow A
b. Compared to cow B, milk yield would increase in cow A
c. Relative to cow B, milk yield would be unaffected in cow A
d. Relative to cow B, endogenous secretion of cortisol would most likely be decreased in cow A
e. More than one answer is correct
e.
Exogenous estrogen administration has been shown to
a.reduce milk yield in a variety of species
b. inhibit lactation by disrupting myoepithelial cell function
c. affect milk production regardless of whether progesterone is also administered
d. all of the above
d.
Proven strategies for evaluating milk yield in various species include
a. weigh-suckle-weigh
b. litter growth index
c. measurement of total RNA in mammary parenchyma
d. all of the above
d.
What changes must occur for lactogenesis to be successful?
a. differentiation of cellular organelles
b. increase in enzymatic activity for milk secretion
c. marked increase in mammary RNA
d. all of the above
d.
Placental lactogen:
a. is secreted into fetal, not maternal blood in cows
b. may bind to the prolactin receptor
c. is absent in rabbits
d. is likely not normally lactogenic in cattle
e. all of the above
e.
Which of the following is most lactogenic?
a. progesterone
b. adrenocorticotrophic hormone (ACTH) injected into a normal pregnant rat with all of her endocrine glands intact
c. ACTH injected into an adrenalectomized pregnant rat
d. insulin injected into a normal pregnant rat with all of her endocrine glands intact
e. insulin injected into a pregnant rat with all of her endocrine glands removed
b.
Which of the following would not be useful as a measure of lactogenesis?
a. alpha-lactalbumin content of mammary tissue
b. histological differentiation of organelles of mammary cells
c. incorporation of bromodeoxyuridine into cells during the S-phase (DNA synthesis)
d. lactose content of mammary tissue
c.
Which of the following, if administered exogenously, would reduce the number of prolactin receptors in mammary tissue?
a. large amounts of prolactin
b. progesterone
c. chronic, long-term administration of ergot alkaloids
d. all of the above
e. none of the above
d.
Placental lactogen (PL) can induce mammary growth by binding to receptors for which homologous hormone(s)?
a. cortisol
b. follicle-stimulating hormone (FSH)
c. growth hormone (GH)
d. prolactin (PL)
e. all of the above
f. more than one answer but not all answers are correct
f.
Which of the following would likely be anti-mammogenic during pregnancy?
a. chronic administration of an estrogen-blocking compound
b. chronic undernutrition
c. insulin injections
d. high secretion of progesterone
e. all of the above
f. more than one but not all answers are correct
f.
Creating a lesion that disrupts function of the pituitary stalk would likely ___________ secretion of prolactin from the anterior pituitary.
increase
Secretion of growth hormone
a. is inhibited by somatostatin, which is secreted from the hypothalamus into the portal vessels of the pituitary stalk
b. is stimulated by growth hormone releasing hormone (GHRH)
c. occurs in the anterior pituitary
d. all of the above
e. more than one but not all answers are correct
d.
Hormones that support or indirectly promote mammary cell proliferation include
a. glucocorticoids
b. insulin
c. thyroid hormone (thyroxine)
d. all of the above
d.
The ductal framework of the mouse mammary gland
a. extends to the periphery of the fat pad before alveolar development begins
b. grows in exactly the same manner as the ductal framework of the bovine mammary gland
c. develops with coordination from the terminal end bud (TEB) structures
d. is an excellent model for how human mammary tissue develops
e. all of the above
f. more than one but not all answers are correct
f.
Estrogen from the ovary acts in an _______ fashion to stimulate prepubertal mammary development.
a. autocrine
b. endocrine
c. intracrine
d. paracrine
b.
Which type of hormone is the primary stimulator of alveolar development in a pregnant mammal?
a. catecholamine
b. glycolipid
c. neurohormone
d. steroid
d.
Growth hormone (GH) receptors
a. are located on the membrane of bovine mammary epithelial cells
b. are present in the cytoplasm of mammary fibroblasts in stroma
c. are located on the basement membrane of mammary epithelial cells
d. none of the above
d.
Which of the following hormones, given exogenously, would best stimulate ductal growth in a hypophysectomized animal?
a. growth hormone
b. insulin
c. progesterone
d. thyroxine
a.
Regulator/source and major actions on mammary gland of Thyroid-Stimulating Hormone are:
Thyroid Releasing Factor (TRF); Enable normal development an dfunction
Regulator/source and major actions on mammary gland of Insulin
Pancreas; Enable normal development and function
Regulator/source and major actions on mammary gland of ACTH
Corticotropin-releasing factor (CRF); enable normal development and function and alveolar differentiation
