Mammary Glands Overview

Mammary Glands

• Support System: Fine connective membranes separate front and rear quarters. A median suspensory ligament and connective tissue attach the udder to the abdominal wall. A lateral suspensory ligament supports the udder.

• Median Suspensory Ligament (MSL): Crucial for udder support. Divides the udder into right and left halves. Composed of elastic tissue, enabling expansion for milk fill.

• Pendulous Udder: Occurs when supporting ligaments weaken and the cord-like attachment stretches. This results in a sagging udder.

• Disadvantages: Cleaning and milking difficulties, injury risk, and mastitis risk.

Mammary Gland Structure

• Skin: Fine connective tissue layer beneath the skin.
• Connective Tissue: Connects mammary front quarters to the abdominal wall.
• Lateral Suspensory Ligaments (LSL): Support structures
• Median Suspensory Ligament (MSL): Main support structure
• Subpelvic Tendon: Part of the supportive structure.

Duct System

• Teat Meatus: Small canal (.5-1 cm long) at the teat tip, only sphincter in the gland
• Furstenburg's Rosette: Seven to eight loose membrane folds above the teat meatus
• Teat Cistern: Cavity within the teat (30-90 ml capacity)

Mammary Duct System

• Lobes: Contain lobules with small ducts, blood capillaries, and secretory cells.
• Lobules: Groups of alveoli.
• Alveoli: Tiny sacs with epithelial cell walls that produce milk.
• Gland Cistern: (400ml)
• Teat Cistern: (30-40ml)

Primary Defense Mechanisms

• Teat Sphincter: Important barrier against udder bacteria.
• Mastitis: Damage to the teat end frequently leads to udder inflammation.

Secretory Tissue

• Lobe: Group of lobules.
• Lobule: Group of alveoli - each lobule contains alveoli (many)
• Alveoli: Cluster of sacs, single layer of epithelial cells, central lumen.

Alveoli (Microscopic)

• Myoepithelium: Surrounds alveoli, contraction pushes milk into ducts.
• Lumen: Central space within alveoli.
• Epithelial Cells: Produce milk (secretory cells)
• Capillary: Blood vessel - delivers milk nourishment to alveolar cells
• Passage of Milk: Milk moved to gland cistern through ducts.

Suckling

• Neural Pathway: Suckling stimulates Hypothalamus, which sends signal via neural pathway to the brainstem.
• Neuroendocrine Cells: Produce oxytocin.
• Posterior Pituitary: Stores Oxytocin, released into the bloodstream.
• Oxytocin: Stimulates myoepithelial cells that cause milk letdown.
• Milk Production: Aveoli produce milk. oxytocin for Milk letdown by myoepithelial cells contraction.

Postnatal Development

• Stages: Tubular, Enlargement, Quarter, Half, various time intervals.
• Stages of Development: From birth to puberty: shows the stages of development from birth to puberty of mammary glands, with the stages described via timeline (e.g., birth-1 month, 3-4 months, 4-9 months, etc).
• Histological Stages (Microscopic Views): Virgin, Pregnancy, Lactation, and Involution, which shows the development stages in the mammary glands with microscope view.
• Embryonic Development: The early periods in the development of the udder tissues are illustrated using diagrams of developing tissues.

Explore the essential components and structures of mammary glands. Learn about the supporting ligaments, the median suspensory ligament's role, and the implications of a pendulous udder. This quiz delves into the anatomy and functionality important for understanding udder health.