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Milk's 4 main abilities or attributes
- 1. Antimicrobial
- 2. hydration
- 3. thermoregulation
- 4. source of Calcium via caseins
Mammary glands are most closely related to what type of gland?
Apocrine gland or scent gland
How many mammary glands and openings per teat do kangaroos have?
4 abdominal with 15 openings per teat
How many mammary glands and openings per teat does a cat have?
- 2 Thoracic+ 6 Abdominal=8
- with 3-7 openings/teat
How many mammary glands and openings per teat does a dog have?
- 2 Thoracic + 6 abd + 2 inguinal=10
- 8-14 openings/teat
How many mammary glands and openings per teat does a mouse have?
- 4 thoracic + 2 abd + 4 inguinal=10 with
- 1 opening/teat
How many mammary glands and openings per teat does a rats have?
- 4 thoracic + 4 abd + 4 inguinal=12 with
- 1 opening per teat
How many mammary glands and openings per teat does a pig have?
4 thoracic + 6 abd + 2 inguinal= 12 with 2 openings per teat
An extra nipple only
An extra, full mammary gland with lactation
Ducts and all the structures we are growing are made of what type of cells?
What is responsible for the opening or lumen of the end duct?
How is it that ducts don't ever grow more than 0.25mm to each other?
Local growth inhibiting factors are secreted
What signals the ducts not to grow any further?
The outer edge of the fat pad
Parenchyma is a way of referring to what?
to all the active secretory tissue of an organ.
2 ways breasts can grow by are:
- Fat deposition
- Epithilelial cells growing & multiplying
What signals the ducts not to grow any further?
The outer edge of the mammary fat pad or local growth inhibiting factors
What are the 2 phases of allometeric growth prior to pregnancy?
Puberty and conception
contains how many cells?
holds how much milk?
- each is ~100 microns across
- contains 100 epithelial cells
- holds ~ 1/5 drop if milk
150-220 alveoli are arranged into a ?
multiple lobules are arranged into?
This hormone is the driving force in MG development
Most common examples of Selective Estrogen Receptor Modulators (SERMs) are?
tamoxifen and raloxifene, they function to block estrogen from binding the estrogen receptor & activating target genes.
Steroid hormones (estrogen, progesterone, androgens, glucocorticoids) signal via what type of receptor?
nuclear hormone receptors that act as transcription factors after binding hormone.
Estrogen stimulates the ducts to grow via formation of ?
Estrogen primes the epithelial cells to make?
- progesterone receptors at the level of gene transcription
- -cells are able to repond to P due to increased levels of the PR
- -E +P leads to increased branching of the ductal structures
- -P alone doesn't do much, req.s E
About how many epithelial cells make up an alveolus?
From what type of gland did the mammary gland most likely evolve?
Allometric growth occurs during which 2 stages of mammary gland growth/function?
What does hematoxylin stain?
all cell nuclei
What hormones are required for FULL lobulo-alveolar development?
What is the abundant, antibacterial, structural protein found inside the bovine teat?
What are the primary structures that "direct" or "facilitate" ductal elongation into the mammary fat pad during growth?
During what periods of development do end buds appear?
onset or just before puberty and proestrus/estrus of each cycle
Describe the process of mammary gland development in the embryo
- 1.ectodermal thickening due to cell migration
- 2. mesoderm surrounds ectodermal thickening to become future stroma
- 3. formation of mammary band/streak/line/milk ridge
- 4. segregation into discrete hillocks (future site of MG)
- 5. mesenchyme pushes up future nipple region
- 6. epidermal sprout encroaches into underlying mesenchyme
- 7. mesenchyme induces epithelial sprout to grow inward due to growth factors
- 8. formation of bld vessels around epithelial sprout
- 9. simply branched structure present at edge of fat pad by birth.
How does the process of MG development in the embryo differ in males and females?
Mesenchyme responds to testosterone from male to pinch off epithelial connection in certain species.
What are the parts of a cow's teat?
- teat cistern
- streak canal
- furst rosette
- keratin plug
- cricoid rings
- keratinized lining
What are the5 methods you can use to measure the growth of the MG?
- 1. DNA/RNA content-reqs equip & kill animal
- 2. count # of cells- very difficult & kill animal
- 3. MG weight- kill animal
- 4. Label dividing cells- cell proliferation
- 5. MG volume- not accurate, doesn't acct for parenchyma, milk volume alters
Estrogen's role in MG development/growth
- 1. Stimulates ductal growth
- 2. stimulates terminal end buds
- 3. cooperates w GH/IGF-1 during puberty
- 4. helps induce IGF-1
- 5. induces progesterone receptors/ expression
What is Progesterone's role in MG growth and development?
- 1. Stimulates ductal branching
- 2. Stimulates alveolar development
- 3. Cooperates w prolactin during pregnancy
- 4. Induces HGF/works via HGF
- 5. Acts on progesterone receptors
Carnoy's fixative is used to stain what?
the nuclei of epithelial cells, will turn them purple when making whole mounts.