Breast Anatomy

Question 1

Where are the breast positioned

Answer 1

Bilateral compounds secretory glands
Known as mammary glands
Positioned between 2 and 6th rib of thorax extending laterally from sternum to the axilla and laying anterior to the pectoralis major muscle

Question 2

Summary of anatomy

Answer 2

Has fat and glandular tissue
Separated by connective tissue
Into lobes
Each lobe is subdivided into lobules
Lobules consist of alveoli and ducts

Question 3

What are the lobes

Answer 3

4 - 8 lobes in each breast composed of glandular tissue
Divided by connective tissue and adipose layer

Question 4

What are the lobules

Answer 4

Subdivision of each lobe consisting of alveoli and latiferous ducts
Collections of 10-100 alveoli for one lobule

Question 5

What is alveoli

Answer 5

Basi glandular unit of the breast
Contain acini cells which are responsible for secreting milk and are surrounded by myo epithelial cells composed of smoot muscle
Lymphoctyes or monocytes are found wedged between the secretory - acini - cells of the alveoli and have migrated there
They play a role in loca production of antibodies in the form of immunoglobins A (IgA) fo secretion of beast milk

Question 6

What is the ductal system

Answer 6

Complex system of lactiferous ducts
Lactiferous ducts arise from alveoli and unite to form larger ducts
Transport milk to nippple
Resting diameter 1 - 1.4mm but during milk ejection can dilate by up to 58%
Ducts near to pile are more spermicidal and easily compressed

Question 7

Mammogenesis

Answer 7

Fetal - branching morphogenetic- development of the ductal system in utero, mammary - specific cells present from 4-6 weeks gestation this is irrespective of sex
Neonatal - from birth some glandular tissue is presents and milk may be produced - because has been with women hormones

Question 8

Breast development in puberty

Answer 8

Sexually dimorphism breast development - influence of hormones like oestrogen and progesterone
Usually first secondary sex characteristic
Typical age of onset of breast development is 8.5 to 13.5
Ductal development and branching annd lobular development occurs
Nipple size increase and primary areole becomes pigmented
Cyclical changes occur

Question 9

Breast development in pregnancy

Answer 9

Glandular development occurs under the influence of progesterone
Ductal development occurs under the influence of oestrogen
Colusrim is synthesised but lactation is suppresses under the influence of placental hormones