Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Structure & Function 5 > Mammary Glands & Lactogenesis > Flashcards

Mammary Glands & Lactogenesis Flashcards

1
Q

why are mammals mammals?

A

they have mammary glands (mostly)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

failure to produce milk (agalactia) =

A

leads to failure to reproduce
milk has evolved to be the ideal diet after birth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are mammary glands?

A

modified enlarged sweat glands
(compound tubuloalveolar glands)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what does each mammary gland consist of?

A

consist of Ductular and secretory alveolar cells (parenchyma)
Heterogenous matrix (stroma): myoepithelial cells, adipocytes, fibroblasts
Blood supply, lymph drainage, nerve supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

empty udder weighs ? in dairy cow:

A

weighs 10-30kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

total milk storage capacity can exceed?

A

30L in some breeds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

stages of mammogenesis?

A

birth to puberty
puberty
conception to parturition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

birth to puberty stage of mammogenesis?

A

isometric growth
connective tissue and fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

puberty stage of mammogenesis?

A

allometric growth - adipose tissue and secretory ducts are formed, invasion of secretory tissue into fat pad
repeated oestrus cycles result in the formation and growth of duct and alveolar framework
prolactin and growth hormone allow for rapid development
provides basis for future milk synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

conception to parturition stage of mammogeneis?

A

allometric growth, fastest stage of proliferation
adipocytes released in fat pad
extensive lobulo-alveolar structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is milk secretion?

A

this is the synthesis of milk by the alveolar cell and its transfer from the alveolar cell into the alveolar lamina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

when the milk is ejected from the alveoli, where does it go?

A

it is ejected from the alveoli into the ducts and cisterna to be consumed by the neonate during suckling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

lactogenesis?

A

onset of milk secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

galactopoiesis?

A

maintenance of milk secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

two types of hormonal changes are essential for inducing lactogenesis, what are these?

A

decreased secretion of inhibitory hormones
increased secretion of stimulatory hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

hormones that primarily affect lactogenesis are?

A

progesterone
oestrogens
cortisol
prolactin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how does progesterone control milk secretion?

A

stimulates lobulo-alveolar development during pregnancy
principle factor for preventing both parturition and lactation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how does oestrogens (oestradiol) control milk secretion?

A

stimulates growth and differentiation of ductal system
high levels also prevent lactation during pregnancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how does cortisolcontrol milk secretion?

A

induces growth of rough endoplasmic reticulum and the Golgi apparatus of the epithelial cells –> essential for prolactin to have an optimal effect in initiating lactation
progesterone competes with cortisol in binding to intracellular receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how does prolactin control milk secretion?

A

it increases in the final stages of pregnancy (5-10 fold in cows)
removal of progesterone block that initiates parturition also removes inhibition of prolactin receptor synthesis
Binds to membrane receptors now available -> activate intracellular tyrosine kinases -> activate genes coding for proteins within mammary epithelium
Increases the transcription of milk protein genes –> α-lactalbumin (maintains synthesis of lactose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is lactose responsible for?

A

responsible for the osmotic pressure in milk, therefore the volume of milk mirrors the lactose content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what types of factors are important for maintenance of milk production?

A

both hormonal and local factors are important for maintenance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

why is milking essential?

A

it is essential for continued production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what secretes prolactin?

A

anterior pituitary gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what inhibits prolactin secretion?
inhibited by dopamine --> suckling has inhibitory effect on dopamine secretion
26
what secretes oxytocin?
posterior pituitary gland
27
what is milk production indirectly dependent on?
on other hormones: insulin and growth hormone and cortisol and triiodothyronine (T3)
28
how do insulin and growth hormone affect milk production?
regulate metabolism to ensure adequate substrate supplies
29
how do cortisol and triiodothyronine (T3) affect milk production?
required for secretory activity of alveolar epithelial cells
30
what are the local factors that affect milk production?
intramammary pressure --> feedback inhibitor of lactation FIL --> inhibits milk synthesis
31
describe the mammary gland in a cow, ewe, goat:
1 canal/cistern per teat
32
describe the mammary gland of a sow and mare:
2-3 ducts per teat
33
describe the mammary gland of a bitch, queen, mouse, rat, rabbit:
5-6 ducts per teat
34
in all domestic species - describe the lactation curve:
milk production increases gradually during early post-partum, peaks, plateaus and then gradually declines
35
what is milk production mediated by in all domestic species?
mediated by the amount of milk consumed by offspring (or how many times manually milked)
36
milking twice a day gives how much more milk than when milking once a day?
gives 40% more than milking once a day
37
how much more milk does milking 3 times a day give?
a further 5-20% increase
38
how much more milk does milking 4 times a day give?
a further 5-10% increase
39
what does increased milking result in?
it decreases mammary pressure and increases prolactin levels, therefore increases milk production
40
prior to suckling, where is the milk mostly found?
in the alveolar lamina and the fine ducts draining the alveoli
41
what does the small diameter of the alveoli network allow?
means that there is a strong resistance to milk flow
42
where is 70-80% of milk located between sucklings?
in the milk ejection reflex (milk let down)
43
what is needed in order to remove milk?
need an active mechanism - milk ejection reflex
44
what happens during the milk ejection reflex?
nerve impulses are elicited when offspring suckle impulses travel through afferent nerves to hypothalamus Nerves in hypothalamus are stimulates causing posterior lobe of the pituitary to release oxytocin Oxytocin causes myoepithelial cells that surround the alveolus to contract milk is then squeezed out of each alveolus into small ducts Milk travels to the gland cistern ready to be removed by the neonate
45
how does oxytocin travel to the mammary gland
Oxytocin travels to the mammary gland in the blood stream
46
what type of reflex is the milk ejection reflex?
neuroendocrine reflex
47
48
give examples of what will inhibit the milk ejection reflex:
anxiety unusual/painful external stimuli oxytocin secretion is reduced inhibiting the response of the myoepithelial cells reduced blood flow to the udder
48
other than oxytocin, what can also cause the myoepithelial cells to contract?
abrupt mechanical force - e.g. lambs pushing hard against udder
48
what inhibits milk ejection reflex?
the activation of the sympathetic nervous system
48
meaning of cessation?
the process of ending or being brought to an end
49
when young are weaned - what happens to their suckling?
it is reduced or stopped
49
FIL?
feedback inhibitor of lactation
50
what causes cessation of lactation?
suckling reduces milk accumulates in alveoli intramammary pressure rises FIL levels increase locally milk synthesis reduced by reducing blood flow through alveolar capillaries Effect is autocrine Milking removes the local inhibition No milking allows FIL to increase until lactation ceases entirely Apoptosis of secretory cells
51
52
53
meaning of autocrine?
relating to a substance secreted by a cell and acting on surface receptors of the same cell
54
Why is mammary involution essential?
it allows the gland to recover and develop new secretory tissue for subsequent lactations
55
when do nutritional requirements of the neonate change?
in postnatal period so milk composition change to adapt to neonate's requirements (e.g. colostrum, regular milk)
56
where does colostrum accumulate?
in the mammary alveoli in the final weeks of pregnancy
57
what does colostrum contain?
more protein, fat, minerals and vitamins than regular milk and has LOWER levels of lactose
58
describe the energy levels in colostrum of cows:
contains 2x energy per unit volume compared to regular milk
59
what benefit does colostrum have?
it enhances the chances of survival for the offspring as it contains high levels of immunoglobulins
60
Why is colostrum particularly important in ruminants, foals and piglets?
because no immunoglobulins are transferred via the placenta - colostrum is the only way of them getting immunoglobulins
61
maximal intestinal absorption of immunoglobulins occurs when?
in the first 6 hours of life and ceases by 24-48 hours
62
immunoglobulins in milk?
they can still provide some local GI protections after absorption ability lost but offspring would be healthier if they consume the colostrum in the first 6 hours
63
describe the fat and protein in the milk throughout lactation:
fat + protein decreased and gradually rises later in lactation
64
64
65

Structure & Function 5 (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions