Mammary gland Flashcards
(109 cards)
1
Q
Mammary buds develop as downgrowths from _____?
A
Thickened mammary crests
2
Q
Mammary crests are thickened strips of _____ that extend from _____ to ____?
A
Ectoderm; From the axillary to the inguinal regions
3
Q
When do mammary crests appear?
A
During the fourth week
4
Q
In humans, where do mammary crests normally persist?
A
In the pectoral area
5
Q
Each primary mammary bud gives rise to several ____
A
Secondary mammary buds
6
Q
What do secondary mammary buds develop into?
A
Lactiferous ducts and their branches
7
Q
What induces canalization of mammary buds?
A
Placental sex hormones entering the fetal circulation
8
Q
Surrounding mesenchyme gives rise to the ____ and ___ of the mammary gland
A
fibrous connective tissue and fat
9
Q
Canalization of mammary buds continue until_______
A
late gestation
10
Q
By term, how many lactiferous ducts are formed?
A
15 to 19
11
Q
_____ gives rise to the fibrous connective tissue and fat of the mammary gland
A
Surrounding mesenchyme
12
Q
The structure that becomes depressed during the late fetal period at the site of origin of the mammary gland is
A
Epidermis (forming a shallow mammary pit)
13
Q
At birth, how are the nipples typically formed?
A
Poorly formed and depressed
14
Q
What causes the nipple to rise from the mammary pit after birth?
A
Proliferation of the surrounding connective tissue of the areola
15
Q
Smooth muscle fibers of the nipple and areola differentiate from _____
A
Surrounding mesenchymal cells
16
Q
What is the state of mammary glands in newborn males and females?
A
Rudimentary and identical, often enlarged
17
Q
____ are present in the breasts of newborns
A
Lactiferous ducts
18
Q
What structures are absent in the breasts of newborns?
A
Alveoli
19
Q
Before puberty, there is little branching of ____ in the breast
A
Lactiferous ducts
20
Q
Rapid enlargement of female breasts at puberty is due to what two main factors?
A
Development of mammary glands and increased deposition of fibrous stroma and fat
21
Q
At what age does full development of the female breast occur?
A
Approximately 19–20 years
22
Q
What is the developmental state of lactiferous ducts in male breasts throughout life?
A
Remain rudimentary
23
Q
What abnormality results from failure of nipple elevation during childhood?
A
Inverted nipple
24
Q
During what age range does breast enlargement occur in females at puberty?
A
12–15 years
25
Histologically, mammary glands within the breast are classified as?
Compound tubuloalveolar glands
26
How many lobes radiate out from the nipple in a mammary gland?
15 to 20 lobes
27
What separates the lobes of mammary glands from one another?
Adipose and collagenous connective tissue
28
What are the major components of milk? 8
Proteins, lipids, lactose, lymphocytes, monocytes, antibodies, minerals, and fat-soluble vitamins
29
What is the primary function of milk?
Provide the proper nourishment for the newborn
30
Mammary glands develop in the same manner and are of the same structure in both sexes until when?
Puberty
31
What causes further development and structural changes within the mammary glands in females at puberty?
Changes in hormonal secretions
32
Secretions of estrogen and progesterone from the ovaries and later the placenta, and prolactin from acidophils of the anterior pituitary gland initiate development of ___ and ___
Lobules and terminal ductules
33
Which 3 hormones initiate development of lobules and terminal ductules?
Estrogen, progesterone, prolactin
34
The hormone secretion necessary for the full development of the ductal portion of the breast is
Glucocorticoids
35
Full development of the ductal portion of the breast also requires further activation by _____
Somatotropin
36
Increase in connective tissue and adipose tissue within the stroma causes _____
the mammary gland to enlarge
37
At what age does full development of the mammary gland occur?
About 20 years of age
38
When do minor cyclic changes occur in the breast?
During each menstrual period
39
Major changes occur in the mammary gland during ____ and ____
Pregnancy and lactation
40
After age 40, what begins to atrophy in the breast? 3
The secretory portions, some ducts, and connective tissue elements
41
Each lobe of the mammary gland is drained by ___
Its own lactiferous duct
42
Lactiferous ducts lead directly to the ___ where it opens onto its surface
Nipple
43
Before reaching the nipple, each lactiferous duct is dilated to form ____
Lactiferous sinus
44
The lactiferous sinus serves what function?
Milk storage
45
Near the opening at the nipple, the lactiferous ducts are lined by what type of epithelium?
Stratified squamous keratinized epithelium
46
The lactiferous sinus and the lactiferous duct leading to it are lined by what type of epithelium?
Stratified cuboidal epithelium
47
Smaller ducts leading to the lactiferous duct are lined by what type of epithelium?
Simple columnar epithelium
48
What type of cells wrap around developing alveoli and become functional during pregnancy?
Stellate myoepithelial cells
49
Stellate myoepithelial cells are located between the ____ and the ____
epithelium and basal lamina
50
Lactating glands are activated by elevated surges of ___ and ___ during pregnancy
estrogen and progesterone
51
What happens to the terminal portions of the ducts during pregnancy?
They branch and grow
52
What are the secretory units that develop from terminal portions of the lactiferous ducts during pregnancy?
Alveoli
53
What causes the breasts to enlarge as pregnancy progresses?
Hypertrophy of glandular parenchyma and engorgement with colostrum
54
A protein-rich fluid in preparation for the newborn is called
Colostrum
55
What hormone activates the secretion of milk after birth?
Prolactin
56
Prolactin is secreted by which cells?
Acidophils of the anterior pituitary gland
57
What replaces colostrum after birth?
Milk
58
Hypertrophy of glandular parenchyma and engorgement with colostrum causes breast to enlarge when?
Pregnancy
59
Development of mammary glands and increased deposition of fibrous stroma and fat causes enlargement of female breast when?
Puberty
60
The circular, heavily pigmented skin in the center of the breast is called the ___
Areola
61
Areola contains ____ and ___ glands at its margin as well as ______ that resemble both sweat and mammary glands
Sweat glands and sebaceous glands; Areolar glands (of Montgomery)
62
A protuberance covered by stratified squamous epithelium containing the terminal openings of the lactiferous ducts is the ____
Nipple
63
In the center of the areola is the ______
Nipple
64
The nipple is covered by what type of epithelium?
Stratified squamous epithelium
65
The core of the nipple is composed of what type of connective tissue?
Dense collagenous connective tissue
66
The core of the nipple also contains abundant ______ fibers connected to the surrounding skin or interlaced within the connective tissue
Elastic
67
A rich component of ______ cells is present in the core of the nipple
Smooth muscle
68
The smooth muscle fibers in the nipple are arranged in what two ways?
(i) circularly around the nipple and (ii) radiating longitudinally along its axis
69
What causes erection of the nipple?
Contraction of the smooth muscle fibers
70
Most of the sebaceous glands located around the lactiferous ducts open where?
Onto the surface or sides of the nipple
71
Some sebaceous glands open into the lactiferous ducts just before ____
Before the ducts open onto the surface
72
Prolactin is responsible for _____ in the mammary gland?
Milk production
73
Which hormone is responsible for the milk ejection reflex?
Oxytocin
74
Although the mammary gland is prepared to secrete milk before birth, ____ prohibits this secretion
Certain hormones
75
What event removes hormonal inhibition of milk secretion and allows prolactin stimulate milk production?
Detachment of the placenta
76
After placenta detachment, what hormone from the anterior pituitary stimulates milk production?
Prolactin
77
Before full milk production, ____ is secreted for the first 2 or 3 days?
Colostrum (protein-rich thick fluid)
78
Colostrum is rich in which vitamin and electrolytes?
Vitamin A, sodium, and chloride
79
What types of immune cells are found in colostrum?
Lymphocytes and monocytes
80
What immunoglobulin is predominant in colostrum and milk for passive immunity?
Immunoglobulin A (IgA)
81
Name three additional components of colostrum apart from immune cells and immunoglobulin
Minerals, lactalbumin, and antibodies
82
What day is milk usually produced by after parturition?
4th day
83
Milk contains which carbohydrate?
Lactose
84
Milk contains proteins including ______
Caseins
85
6 components of milk
minerals, electrolytes, carbohydrates (including lactose), immunoglobulins (mostly immunoglobulin A), proteins (including caseins), and lipids.
86
8 components of colostrum
vitamin A, sodium, and chloride, also contains lymphocytes and monocytes, minerals, lactalbumin, and antibodies (immunoglobulin A)
87
What triggers a surge in prolactin release necessary for milk production?
Stimuli such as sight, touch, handling of newborn, and anticipation of nursing
88
Once initiated, how is milk production maintained?
It is continuous and milk is stored within the duct system
89
Oxytocin initiates the milk ejection reflex by inducing contractions of ____ cells
Myoepithelial cells around the alveoli and the ducts
90
Myoepithelial cells contract around which structures?
Alveoli and ducts
91
What are the two major types of breast cancer?
Ductal carcinoma and lobular carcinoma
92
Ductal carcinoma arises from which cells?
Ductal cells
93
Lobular carcinoma arises from which structures?
Terminal ductules
94
Why is early detection critical in breast cancer?
Because metastasis to axillary lymph nodes and further to lungs, bone, and brain worsens prognosis
95
What are two methods recommended for early detection of breast cancer?
Self-examination and mammography
96
Development of rudimentary lactiferous ducts in male mammary tissue is termed ___
Gynecomastia
97
Gynecomastia is associated with what hormonal imbalance?
Decreased ratio of testosterone to estradiol
98
What syndrome is associated with gynecomastia in 80% of cases?
Klinefelter syndrome (XXY)
99
Athelia refers to what condition?
Absence of nipples
100
Amastia refers to what condition?
Absence of breasts
101
Athelia and amastia are rare congenital anomalies resulting from what developmental failure?
Failure of development or disappearance of mammary crests or mammary buds
102
Hypoplasia of the breast is more common and often associated with what syndromes?
Gonadal agenesis and Turner syndrome
103
Polymastia refers to what anomaly?
Extra breast
104
Polythelia refers to what anomaly?
Extra nipple
105
Polymastia and polythelia occur in what percentage of the female population?
Approximately 1%
106
Polymastia is inheritable T or F
True
107
Extra breast or nipple usually appears in what location?
Just inferior to the normal breast
108
Inverted nipples occur when nipples fail to do what?
Elevate above the skin surface after birth
109
Inverted nipples remain in what position?
Their prenatal location
