mammary physiology Flashcards
Mammary Physiology quiz 2-1
what are the 4 defining characteristics of mammals?
Mammary glands
Sebaceous glands
Sweat glands
Hair
What type of secretion consists of disintegrated cells of the gland itself?
Holocrine
During what type of secretion are components synthesized and secreted as part of the cell but the cell remains functional?
Apocrine
What type of secretion is important for evaporative cooling, and involves components being synthesized and secreted as part of the cell but the cell remains functional? These follicles are activated during puberty.
Merocrine
Which type of milk secretion occurs when fat droplets are formed in cytoplasm, migrate to apical end of cell, and are pinched off?
Apocrine
Which type of milk secretion occurs when protein and lactose are packaged into secretory vesicles in Golgi apparatus and are released during exocytosis?
Merocrine
Describe the suspected evolution of the mammary gland in monotremes (prototherians):
- mammals that lay eggs
- most simple compared to marsupials and eutherians
- instead of nipples they have mammary patches which evolved from sweat glands
Describe the suspected evolution of the mammary gland in marsupials (metatherians):
- characterized by giving birth to relatively undeveloped young that then develop in mother’s pouch
- more complex than monotremes but less complex than eutherians
-varying number of teats within pouches depending on species
Describe the suspected evolution of the mammary gland in eutharians (placentals)
- undergo extensive development in the womb
- most complex mammary glands
- milk is richest in nutrients
The purpose of mammary glands is to _________ and its evolutionary precursor was likely ____________. The current hypothesis is that __________.
- supply nutrients and protective factors to support offspring and to pass on genes
- an early secretory skin gland
- the first secreted substance kept eggs moist and contained factors that aided development
What are the nutritive secretions of the mammary gland?
- milk
- colostrum
Malignancy depends on several phenomena. What are the major ones? Why do they matter?
- viruses and bacteria
- radiation
- genetics: mutations and DNA damage can disrupt normal functioning genes and can activate oncogenes or inactivate tumor suppressor genes
- diet
- hormones
What are the non-nutritive secretions of the mammary gland?
- Antibodies (immunoglobulins)
- lactoferrin: iron-binding protein
- lysozyme: enzyme that hydrolyzes bacterial walls
- lactoperoxidase: oxidizes bacterial components
- regulatory proteins like IGF-1 and leptin that aid in neonate development
What is angiogenesis? What is its role in cancer
- process by which new blood vessels are formed from pre-existing blood vessels
- essential for tumor growth, invasion and metastasis due to increased blood supply
Describe the role of estrogen in normal and malignant breast physiology.
- normal: produced by follicles of the ovary; stimulates lactogenesis (development and maintenance of mammary gland) by encouraging growth and branching of ductal system and proliferation of epithelial cells
- cancerous: stimulates proliferation of ER+ breast cancer cells
- Describe the role of progesterone in normal and malignant breast physiology.
- normal: regulates growth and differentiation of breast tissue and alveolar epithelial cells as well as production of milk proteins
- cancerous: enhances proliferative effects of estrogen
What are BRCA-1 and BRCA-2? Why should we care?
- human genes that produce tumor suppressor proteins; mutations of these genes result in breast cancer
What are some environmental factors that alter the risk of breast cancer?
- exposure to hormones
- alcohol consumption
- obesity
- exposure to environmental chemicals/radiation
- night shift work
- tobacco
What is epigenetics?
- genetic changes that result from interactions between a person’s DNA and the environment
- changes are heritable
What are the stages of breast cancer and what are they based on?
- based on tumor size, nodal involvement and metastatic spread
- stage 0: abnormal cells are present but have not spread to nearby tissue (carcinoma in situ)
- stage 1: cancer has spread to other tissue in a small area
- stage 2: tumor is between 20-50 mm and some lymph nodes are involved, or a tumor larger than 50 mm
- stage 3: tumor is larger than 50 mm with more lymph nodes involved
- stage 3: cancer as spread beyond the breast
What is the sentinel node?
- first node to visible after injecting a radiolabel into the breast; first lymph node that cancer cells are most likely to spread to from the primary tumor
- node is dissected and if positive, more axilla dissections will be needed
Treatments for cancer and how they differ from those 50 years ago
Modern treatments:
- lumpectomy + radiation
- mastectomy
- chemotherapy
- targeted therapy (ER or PR+, or HER-2/neu +)
- Nolvadex - competes for binding to estrogen receptor
50 years ago:
- targeted therapies and immunotherapies were not available
- expanded hormone/radiation therapies and surgical techniques
What is HER-2/neu?
- growth-promoting protein on the outside of all breast cells; part of EGF receptor family
- in 20-30% of breast cancers, cancer cells have extra copies of this gene
- these cancers are very aggressive because the gene promotes growth and differentiation
Describe how intensified feeding (feeding more milk to a heifer calf than what was done 40 years ago) can alter milk production in first lactation.
-increased growth and development
- earlier age at first calving
- greater mammary gland development and increased milk production abilities
