lOMoARcPSD|18207238
CHAPTER 17
The Breast
BASIC SCIENCE QUESTIONS
1. How many lactiferous ducts drain into the nipple of the mature female breast?
A. 5-10
B. 15-20
C. 25-30
D. 35-40
Answer: B
The breast is composed of 15 to 20 lobes, which are each composed of several lobules.
Each lobe of the breast terminates in a major (lactiferous) duct (2 to 4 mm in diameter), whic
opens through a constricted orifice (0.4 to 0.7 mm in diameter) into the ampulla of the nipple. (Se
Schwartz 9th ed., p 426.)
2. During pregnancy, alveolar epithelium develops in the breast which is responsible after deliver
for the production of milk. Which portion of the alveolar epithelial cell is responsible fo
production of the fat present in human milk?
A. Endoplasmic reticulum
B. Mitochondria
C. Cell membrane
D. Cytoplasm
Answer: D
With pregnancy, the breast undergoes proliferative and developmental maturation. As the brea
enlarges in response to hormonal stimulation, lymphocytes, plasma cells, and eosinophi
accumulate within the connective tissues. The minor ducts branch and alveoli develo
Development of the alveoli is asymmetric, and variations in the degree of development may occu
within a single lobule. With parturition, enlargement of the breasts occurs via hypertrophy o
alveolar epithelium and accumulation of secretory products in the lumina of the minor ducts.
Two distinct substances are produced by the alveolar epithelium: (a) the protein component o
milk, which is synthesized in the endoplasmic reticulum (merocrine secretion); and (b) the lipi
component of milk (apocrine secretion), which forms as free lipid droplets in the cytoplasm. (See
, lOMoARcPSD|18207238
Schwartz 9th ed., p 427.)
3. The medial mammary artery is a tributary of the
A. 2nd, 3rd, and 4th intercostal arteries
B. Internal mammary artery
C. Thoracoacromial artery
D. Posterior intercostal arteries
Answer: A
The breast receives its principal blood supply from (a) perforating branches of the intern
mammary artery; (b) lateral branches of the posterior intercostal arteries; and (c) branches from th
axillary artery, including the highest thoracic, lateral thoracic, and pectoral branches of th
thoracoacromial artery. The second, third, and fourth anterior intercostal perforators and branche
of the internal mammary artery arborize in the breast as the medial mammary arteries. The later
thoracic artery gives off branches to the serratus anterior, pectoralis major and pectoralis minor, an
subscapularis muscles. It also gives rise to lateral mammary branches. (See Schwartz 9 th ed., p 428
4. Which of the following hormones is primarily responsible for differentiation of the breast duct
epithelium?
A. Estrogen
B. Testosterone
C. Progesterone
D. Prolactin
Answer: C
Estrogen initiates ductal development, whereas progesterone is responsible for differentiation o
epithelium and for lobular development. Prolactin is the primary hormonal stimulus for lactogenes
in late pregnancy and the postpartum period. It upregulates hormone receptors and stimulate
epithelial development. (See Schwartz 9th ed., p 429.)
CLINICAL QUESTIONS
1. Absence of the breast (amastia) is associated with
A. Turner’s syndrome
B. Kleinfelter’s syndrome
C. Poland syndrome
D. Fleischer’s syndrome
CHAPTER 17
The Breast
BASIC SCIENCE QUESTIONS
1. How many lactiferous ducts drain into the nipple of the mature female breast?
A. 5-10
B. 15-20
C. 25-30
D. 35-40
Answer: B
The breast is composed of 15 to 20 lobes, which are each composed of several lobules.
Each lobe of the breast terminates in a major (lactiferous) duct (2 to 4 mm in diameter), whic
opens through a constricted orifice (0.4 to 0.7 mm in diameter) into the ampulla of the nipple. (Se
Schwartz 9th ed., p 426.)
2. During pregnancy, alveolar epithelium develops in the breast which is responsible after deliver
for the production of milk. Which portion of the alveolar epithelial cell is responsible fo
production of the fat present in human milk?
A. Endoplasmic reticulum
B. Mitochondria
C. Cell membrane
D. Cytoplasm
Answer: D
With pregnancy, the breast undergoes proliferative and developmental maturation. As the brea
enlarges in response to hormonal stimulation, lymphocytes, plasma cells, and eosinophi
accumulate within the connective tissues. The minor ducts branch and alveoli develo
Development of the alveoli is asymmetric, and variations in the degree of development may occu
within a single lobule. With parturition, enlargement of the breasts occurs via hypertrophy o
alveolar epithelium and accumulation of secretory products in the lumina of the minor ducts.
Two distinct substances are produced by the alveolar epithelium: (a) the protein component o
milk, which is synthesized in the endoplasmic reticulum (merocrine secretion); and (b) the lipi
component of milk (apocrine secretion), which forms as free lipid droplets in the cytoplasm. (See
, lOMoARcPSD|18207238
Schwartz 9th ed., p 427.)
3. The medial mammary artery is a tributary of the
A. 2nd, 3rd, and 4th intercostal arteries
B. Internal mammary artery
C. Thoracoacromial artery
D. Posterior intercostal arteries
Answer: A
The breast receives its principal blood supply from (a) perforating branches of the intern
mammary artery; (b) lateral branches of the posterior intercostal arteries; and (c) branches from th
axillary artery, including the highest thoracic, lateral thoracic, and pectoral branches of th
thoracoacromial artery. The second, third, and fourth anterior intercostal perforators and branche
of the internal mammary artery arborize in the breast as the medial mammary arteries. The later
thoracic artery gives off branches to the serratus anterior, pectoralis major and pectoralis minor, an
subscapularis muscles. It also gives rise to lateral mammary branches. (See Schwartz 9 th ed., p 428
4. Which of the following hormones is primarily responsible for differentiation of the breast duct
epithelium?
A. Estrogen
B. Testosterone
C. Progesterone
D. Prolactin
Answer: C
Estrogen initiates ductal development, whereas progesterone is responsible for differentiation o
epithelium and for lobular development. Prolactin is the primary hormonal stimulus for lactogenes
in late pregnancy and the postpartum period. It upregulates hormone receptors and stimulate
epithelial development. (See Schwartz 9th ed., p 429.)
CLINICAL QUESTIONS
1. Absence of the breast (amastia) is associated with
A. Turner’s syndrome
B. Kleinfelter’s syndrome
C. Poland syndrome
D. Fleischer’s syndrome
