Slide Set 2: The Mammary Gland Flashcards

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1
Q

The mammary gland is composed of

A

☛ Modified sweat gland
☛ Exocrine gland
☛ Accessory gland to the reproductive system

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2
Q

What are the major components of the mammary gland iin order:

A
  • secretory system
  • ductular system
  • teats
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3
Q

The udder has a complex structure consisting of the following:

A
  • The mammary gland (s) components
  • A supportive system
  • Blood, nerve, and lymph systems
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4
Q

How much does the udder weigh?

A

10-25 kg (empty)

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5
Q

How many glands does the udder have? and what is the structure like? (4)

A

☛ Four separate simple glands (quarters)
☛ Each gland has one teat & one opening
☛ Right & left halves are entirely separate
☛ Rear quarters are bigger than forequarters

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6
Q

Which quarter is bigger in the udder?

A

Rear quarters are bigger than forequarters

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7
Q

How is the udder protected?

A

Skin (10-20% of the empty udder) provides protection but little support

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8
Q

How is the udder attached to skin? How is the udder attached to the abdominal wall?

A

to skin by fine connective tissue

to abdominal wall by coarse connective tissue

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9
Q

What are the two major groups of ligaments of udder?

A

Median Suspensory Ligaments (MSL)

Lateral Suspensory Ligaments (LSL)

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10
Q

Where is median suspensory ligament located? What is the structure like?

A
  • Arise from the midline of the abdomen and extend between the udder halves
  • Divide the udder into two halves (left & right)
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11
Q

The median suspensory ligament consists of:

A

Elastic and fibrous connective tissue

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12
Q

What are the functions of the median suspensory ligament?

A

☛ Provide the primary support for the udder
☛ Provide elasticity needed by the udder to expand as
it fills with milk
☛ Shock absorption

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13
Q

Where is lateral suspensory ligament located? What is the structure like?

A
  • Arise from the tendons around the pubic bone

* Extend along both sides of the udder

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14
Q

The lateral suspensory ligament consists of:

A

Mostly collagen connective tissue (non-elastic)

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15
Q

What are the functions of the lateral suspensory ligament?

A

Provide support to the interior of the udder

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16
Q

How many mammary glands does Doe’s udder has and what are the key characteristics? (deer)

A
  • Two mammary glands drained by 2 teats
  • Size varies considerably
  • Teats are wide at the base and protrude like a funnel from the udder
  • Teats are covered with fine hair Supernumerary teats are common
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17
Q

How many mammary glands does Ewe’s udder has and what are the key characteristics? (sheep)

A
  • Two mammary glands drained by 2 teats
  • Teats and udder are smaller than in goats
  • Gland cisterns are irregular & small
  • Teats are covered with fine hair
  • Supernumerary teats are common
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18
Q

TRUE/FALSE

Gland cisterns of the Ewe’s udder are regular & big

A

FALSE

Gland cisterns are irregular & small

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19
Q

How many mammary glands does Sow’s udder has and what are the key characteristics? (pig)

A
  • 3-10 pairs of glands (average 6-7 pairs)
  • arranged in two parallel row in either side of the ventral median line.
  • There are two openings in each teat and each opening is connected to a separate duct and glandular system.
  • Teats in front produce milk than the ones at the back
  • Supernumerary teats and inverted nipples are common
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20
Q

How many mammary glands does Mare’s udder has and what are the key characteristics? (horse)

A
  • Two mammary glands each with 2 streak canals (4 glands)
  • Teats are flat and broad with blunted tips
  • Teats and udder are covered with fine hair and dark pigments
  • Sweat and sebaceous glands are present
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21
Q

What are the 4 major components of the women mammary gland?

A

1- Lobes
2- milk ducts
3- fat pad
4- connective tissue

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22
Q

How many lobes does human mammary gland have? What are their some key characteristics?

A
  • There are 15-20 lobes/breast
  • Lobes are separated by connective tissue
  • Each lobe is drained by its own lactiferous duct leading directly to the nipples
  • Number and size of lobes varies between women and breasts
  • There are 6-10 large collecting ducts
  • Ducts expand slightly beneath the nipple to form sinuses (ampules)
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23
Q

Where does milk stay before it gets ejected?

A

ampulla

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24
Q

What is areola what are its functions?

A

– Pigmented skin in the center of the breast
– Contains sweat and sebaceous glands
– Contains nerve endings (send suckling signals to the brain)

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25
Q

What is nipple what are its functions?

A

– Terminal point for ducts (lactiferous duct)
– Surrounded by the areola
– During pregnancy, the color becomes darker because of increased pigmentation of the areola and the nipple

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26
Q

The core of the nipple is composed of _________

A

dense connective tissue &elastic fibers smooth muscle cells (circular & longitudinal)

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27
Q

The wrinkling of the skin on the nipple results from _________

A

the attachments of the elastic fibers

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28
Q

The contraction of these muscle fibers is responsible for ______ of the nipple.

A

erection

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29
Q

Most of the _________ located around the lactiferous ducts open onto the surface or sides of the nipple open onto the surface.

A

sebaceous glands

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30
Q

Compare the structure of lactating breast and inactive breast

A
  • the main difference is the size of the lobule
  • in late pregnancy the size of the breast increases.
  • the weight of the breast is 150-200g (non lactating)
  • in lactating female the weight of the breast is 500g
  • if you make a cross section of the lobule you find a group of
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31
Q

What are the components of the mammary tissue? How are they separated?

A

Lactating
- Parenchyma (lobuloalveolar tissue) —> ductular and secretory system

Non-lactating 
- Stroma consists of 
•Connective tissue
• Adipose tissue
• Nerve & blood tissue
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32
Q

What is the function of the connective tissue of mammary gland?

A

Support the ductular & secretory tissues

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33
Q

What is the composition of a desirable connective tissue?

A
  • Minimum connective tissue

- Maximum secretory & ductular tissue

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34
Q

The mammary ductular system starts at the ______ & ends at the ______

A

alveoli

streak canal

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35
Q

What is the order of the mammary ductular system?

A

terminal ductule –> mammary duct –> gland cistern –> teat cistern

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36
Q

What is the largest structure of the mammary gland?

A

Lobule

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37
Q

The lobule is composed of bunch of alveolar cells. Where does the milk go from the lobule after it is secreted?

A

they empty the milk into the alveolar duct tube then join each other to form the mammary duct

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38
Q

Does the milk composition change once the milk is secreted?

A

No change in milk occurs once it moves into the duct.

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39
Q

Where is the milk stored in between milking? Give examples from mammals

A

A- Large reservoirs in ruminants (cisterns)
B- Small reservoirs in rats and guinea pigs
C- No reservoirs in rabbits and humans
Cisterns may hold up to 1⁄2 of the milk in the gland
In B& C, most of the milk produced is located in the lobualveolar tissue

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40
Q

Where do humans store milk in between milking?

A

humans don’t have cistern and they store the milk within the duct or/and the alveolar system

41
Q

What is the teat structure like in udder?

A
  • 4 teats drain a separate gland
  • Fore teats are longer than the rear teats
  • void of hair and sweat glands
  • most innervated part of the udder
42
Q

_______ contracts around the teat canal to control the ease (speed) of milking

A

Sphincter muscle

43
Q

How long is the teat canal and what are its key characteristics?

A
  • 7-16 mm long
  • 0.08 mm diameter
  • Lined with cells that produce bacteriocides
44
Q

What are the key characteristics of teat cistern?

A

• Milk storage (continuous with gland cistern)

45
Q

What is a lobe?

A

A group of lobules

46
Q

What is a lobule?

A

A group of alveoli

47
Q

What is alveoli?

A

A cluster of alveolus

48
Q

What is alveolus (acinus)?

A

A single layer of epithelial cells surrounding a central lumen

49
Q

In an ascending order, the secretory tissue is composed of

A

alveolus
alveoli
lobule
lobe

50
Q

What is the function of the mammary ductular system? What are its structures and key characteristics?

A

Milk storage in cows
☛ Gland cistern is the largest collection point (400 ml)
☛ Teat cistern holds 30-40 ml of milk

51
Q

What is the function of the myoepithelial cells around the alveoli?

A

myoepithelial cell surrounds the alveolus
contractile, squeezes the milk from outside
release the milk from the alveoli to the duct system
they have hormonal receptors - oxytocin (most important hormone for milk ejection

52
Q

What is a mammary barrier?

A

this is a cross section of the alveolar system

the components that sep the blood and the milk

53
Q

What is myoepithelial cell?

A

Muscular smooth cell that contracts the alveolus to expel milk into the lumen

54
Q

The basic unit of milk synthesis is ______

A

Secretory epithelial cell

55
Q

What is the histology of secretory epithelial cell?

A

Cuboidal shape, lining the alveolar lumen is a single layer

56
Q

What are the major components of secretory epithelial cell?

A

☛ Nucleus
☛ Endoplasmic reticulum (rough & smooth ER)
☛ Golgi apparatus
☛ Membranes & junctions

57
Q

What are the membranes of the secretory epithelial cells?

A
  • basement membrane
  • basal membrane
  • apical membrane
58
Q

What is the function of the basement membrane in secretory epithelial cells?

A

separates stromal & epithelial compartments

59
Q

What is the function of the basal membrane in secretory epithelial cells?

A

site of milk precursors uptake by the secretory cell

60
Q

What is the function of the apical membrane in secretory epithelial cells?

A

site of secretion of milk components

61
Q

site of milk precursors uptake by the secretory cell is _________

A

basal membrane

62
Q

site of secretion of milk components _______

A

apical membrane

63
Q

What are the types of cell junctions in secretory epithelial cells?

A
  • tight junctions
  • gap junctions
  • desmosomes
64
Q

What is the functions of the tight junctions in secretory epithelial cells?

A

seals adjacent cells together & prevent leakage of materials through intercellular spaces

65
Q

What is the function of the gap junctions in secretory epithelial cells?

A

route for exchange of molecules between adjacent cells

66
Q

What is the function of the desmosomes in secretory epithelial cells?

A

maintaining cell adhesion

67
Q

What is the function of the Rough Endoplasmic Reticulum in secretory epithelial cells?

A

Site of protein biosynthesis

68
Q

What is the function of the Smooth Endoplasmic Reticulum in secretory epithelial cells?

A

Intracellural channels for material transfer

69
Q

What is the function of the golgi apparatus in secretory epithelial cells?

A

☛ Site of protein packaging (formation of casein micelle) ☛ Site of lactose biosynthesis

70
Q

What is the function of the nucleus in secretory epithelial cells?

A

contains the genetic materials of the secretory cell

71
Q

What is the function of the secretory vesicles in secretory epithelial cells?

A

Transport of protein, lactose & salts from the Golgi to the apical membrane

72
Q

What is the function of the cytoplasm in secretory epithelial cells?

A

☛ Site of fatty acid synthesis
☛ Contains enzymes,
macromolecules & nutrients

73
Q

What are the important arteries that bring oxygenated blood from heart to mammary gland?

A
  1. mammary arteries (external pudic)
  2. cranial mammary artery
  3. caudal mammary artery
  4. aorta
74
Q

Where does external pudic artery feed into?

A

has two branches for each half of the udder

75
Q

Where does cranial mammary artery feed into?

A

front side of the udder

76
Q

Where does caudal mammary artery feed into?

A

rear part of the udder

77
Q

What are the two veins that collect blood from the udder?

A
  1. external pudendal vein

2. subcutaneous vein (milk vein)

78
Q

What are the veins that bring the blood back to the heart?

A
  1. vena cava
  2. external iliac
  3. external pudic
  4. subcutanous abdominal vein
79
Q

How is the teat controlled by the nervous system?

A

two types of control

  1. autonomic (involuntary) divides into sympathetic and parasympathetic
  2. somatic (voluntary)
80
Q

The nervous system in the teat is responsible for:

A
  1. milk ejection

2. milk inhibition

81
Q

How does the nervous system control milk ejection?

A

The highest innervation in all mammary gland there is nerve ending on the teat and the young will suckle and the signals will be sent to the brain to secrete oxytocin. oxytocin will bind to the myoepithelial cell and that will start the contraction of the myeoepithelial tissue

82
Q

Milk ejection has two components:

  1. ________
  2. ________

and the collective name for this is ________

A
  • neural
  • hormonal

NEUROHORMONAL REFLEX

83
Q

How does the nervous system control milk inhibition?

A

milk inhibition is caused by the sympathetic nervous system
that nervous system is activated during stress under stress
VASOCONSTRICTION
less flow to the mammary gland which means less milk. it happens to most of the mammalian species
dairy cows its a big problem. cow comfort which means you need to make the cow happy to avoid stress
happy cows mean more milk

84
Q

How is the nervous system of the mammary gland innervated?

A
  • Innervation of the udder is sparse
  • No direct innervation of the secretory cell
  • No parasympathetic innervation
  • Neural receptors (somatic NS) are present in the skin of the teats and udder (greatest innervation is in the teat)
  • Sympathetic innervation is associated with arteries
85
Q

______ nervous system controls blood flow to the udder

A

Sympathetic

86
Q

______ innervation is associated with arteries

A

Sympathetic

87
Q

Neural receptors (_____ NS) are present in the skin of the teats and udder (greatest innervation is in the teat)

A

somatic

88
Q

Stimulation of the sympathetic nervous system (e.g. stress) causes:

A
  • vasoconstriction of blood vessels
  • reduces blood supply to the mammary gland
  • reduction in milk yield
89
Q

How is the lymphatic system of the mammary gland structured?

A
  • Lymph vessels carry tissue fluid (lymph)from tissue spaces to lymph nodes
  • Lymph nodes filter the tissue fluids to remove foreign materials
  • thoracic duct
  • veins
90
Q

What are the main functions of the lymphatic system in the mammary gland?

A
  • Carries waste products away from active cells
  • Carries chylomicrons
  • Carries immune bodies from lymph nodes
  • Carries co-aggulating proteins
  • Dissipate heat from cells
91
Q

Lymph vessels travel in a ______ direction to the _______ lymph node

A

dorsal-caudal

supramammary

92
Q

Lymph moves only in one direction toward the ______

A

Supramammary lymph node

93
Q

How is the lymphatic system of the mammary gland of dairy cows structured?

A

✰ Dairy cows have two supra-mammary lymph node (one on top of each half of the udder
✰ Valves in lymph vessels cause lymph to move only in one direction
✰ Subcutaneous lymph vessels are very prominent in mature cows
✰ Accumulation of excessive fluid in subcutaneous lymph vessels may cause udder edema (accumulation of fluid between udder skin and secretory tissues)

94
Q

What happens when lymph fluid accumulated in the lymph vessels?

A

Accumulation of excessive fluid in subcutaneous lymph vessels may cause udder edema (accumulation of fluid between udder skin and secretory tissues)

95
Q

Where does the lymphatic fluid drain in women’s breast?

A
  • Lymph drains from superficial to deep space and most lymph exits through retro-mammary space at the rear of the breast
  • Central & lateral parts of the mammary gland (~75%) drain into the axillary lymph nodes
  • 20% drains into internal mammary lymph nodes (inner & outer parts of the breast)
96
Q

Central & lateral parts of the mammary gland (~75%) drain into the ______

A

axillary lymph nodes

97
Q

20% drains into _______ (inner & outer parts of the breast)

A

internal mammary lymph nodes

98
Q

Lymph drains from _________ space and most lymph exits through __________ at the rear of the breast

A

superficial to deep

retro-mammary space