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Related Flashcards
Cards In This Set
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How many lobes are within the breast and what divides them
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The breast contains 20-25 lobes which are seperated by cooper's suspensory ligament which travels between the deep fascia, which connects the breast to the muscle, to the skin
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Describe the duct system of the breast.
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The lobes consists of lobules made up of alveoli which converge to from ductules. Ductules from each lobule converge to form the lactiferous duct which leaves each lobe.
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What is the lactiferous sinus.
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Each lactiferous duct opens onto the nipple, proximal to the opening there is a widening called the lactiferous sinus which is usuallt plugged with keratin in non-pregnant women.
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Outline the marigns of the breast base and what gives the nipple its grainy appearence
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Medially - sternal margin, laterally - midaxiliary line from the 2-6th intercostal space.
the sebecous glands.
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Describe the blood supply and lymph drainage and why is it important?
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It is supplied by the internal and lateral thoracic and the intercostals. It drains superiorly to the infraclavicular and cervical, laterally to the pectoral nodes, inferiorly to the diaphragmatic and medially to the parasternal. Lymph nodes are the common site of cancer metastasis.
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What hormones control the development of breast tissue during pregancy.
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1)human placental lactogen (hPL)
2) Prolactin
3) Oestrogen and progesterone
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Describe the development of breast tissue during pregnancy
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Atrophic ducts - Duct growth - tubuloalveolar growth - milk secretion
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What is the role of prolactin the lactation
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1. Stimulates mammary gland development
2. Stimulates the secretion of milk by the alveoli glands.
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How is the milk secreted?
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1) Merocrine - the protein component is help within intracellular vesicles which fuse with the membrane secreting with no loss of membrane
2) Apocrine - the lipid are free within the cytoplasm and they are released with a portion of the cytoplasm.
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Where is prolactin released from and how is it controlled.
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It is released from the anterior pituitary in accordance to the balance between PRH and PIH (dopamine) secreted from the hypothalamus.
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What effect does suckling have on prolactin secretion?
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Suckling inhibits PIH so it promotes the secretion of prolactin hence the secretion of milk.
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What inhibits milk production during pregnancy?
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The high oestrogen levels.
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What is role of oxytocin?
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It is released in episodic burst every 2-3 minutes and it causes the contraction of myoepthelial cells surrounding the alveoli resulting in expulsion of milk. Suckling promotes the release of oxytocin from the posterior pituitary.
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