VIDEHISTO #58 | Sistema reproductor femenino - Glándula mamaria en reposo y activa

Introduction to the Mammary Gland

Overview of the Class Objectives

• The speaker introduces themselves and outlines the importance of reviewing official bibliography alongside video content.

• Emphasis is placed on understanding key points about the mammary gland, which will be discussed throughout the class.

Anatomy and Structure of the Mammary Gland

General Characteristics

• The mammary gland is a glandular organ located in the thorax, anterior to pectoral muscles, organized radially around ducts leading to the nipple.

• Milk is excreted through these ducts, which culminate in terminal ducts associated with alveoli for milk storage during lactation.

Tissue Composition

• The mammary gland consists of exocrine glands that secrete their contents externally; they are dynamic organs influenced by hormonal changes.

• In non-pregnant individuals, duct systems are active but differ significantly during lactation when lobules develop for milk synthesis.

Functional Units and Stroma Composition

Structural Components

• The functional unit of the breast is identified as the terminal duct unit, consisting of branching ducts ending in terminal ducts surrounded by stroma.

• Stroma includes dense connective tissue and abundant adipose tissue, crucial for understanding pathological studies related to breast health.

Microscopic Observations

• High magnification reveals distinct boundaries between lobules and interlobular stroma filled with loose connective tissue and adipose tissue.

• Epithelial cells within ducts exhibit specific characteristics such as apical cubic shapes and basal positioning, essential for milk secretion processes.

Cellular Dynamics During Lactation

Changes in Cellular Structure

• Comparison between inactive and active mammary glands shows proliferation of lobules with larger alveoli during lactation while stroma decreases in volume.

• Plasma cells present in connective tissues synthesize antibodies critical for newborn immunity via breast milk transmission.

Visual Evidence from Lactating Glands

Mammary Gland Function and Milk Composition

Hormonal Influence on Mammary Gland Structure

• The mammary gland is a dynamic organ, with its morphology and function changing based on hormonal stimuli. Estrogens from ovarian follicles stimulate the ducts, while progesterone from the corpus luteum stimulates lobules.

Lactation and Hormonal Regulation

• During lactation, two key pituitary hormones become significant: oxytocin, which stimulates epithelial cells for milk ejection, and prolactin, which promotes milk component synthesis in alveolar cuboidal cells.

Components of Milk Production

• Various components are synthesized during milk production; lactose is produced by epithelial cells through merocrine secretion. Lipid droplets are also secreted by cuboidal cells.

Role of Antibodies in Milk

• Plasma cells at the end of the mammary gland synthesize antibodies that enter epithelial cells via endocytosis and exit into the alveoli through exocytosis. This process is crucial for providing passive immunity to newborns.

Importance of Breast Self-Examination

• Mothers should perform breast self-examinations five days post-lactation to check for irregularities. This includes visual inspection in front of a mirror followed by manual examination to identify lumps or painful spots.

Annual Check-Ups for Breast Health