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30 Cards in this Set
- Front
- Back
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What type of gland are the mammary glands?
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Highly modified apocrine sweat glands
Compound tubuloacinar glands |
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What kind of secretory epithelium is found?
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Simple cuboidal
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How are the epithelia arranged?
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Into clusters of alveoli which secrete milk into alveolar lumen
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What lies between the epithelial cells and the basement membrane?
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Contractile myoepithelial cells
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What is the purpose of the rich capillary network on the surface of the basement membrane?
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To supply oxygen and nutrients required for milk synthesis
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How are the alveoli arranged?
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Into lobules
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What separates the lobules?
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Connective tissue
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What do the alveoli empty into?
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Intralobular ducts into interlobular ducts into larger ducts
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How do the epithelia change through these ducts?
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Start off being cuboidal but become more columnar and stratified as the ducts increase in size
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Where do the ducts end up?
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Lactiferous duct which turn into lactiferous sinus
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What are the 2 parts of the lactiferous sinus?
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Gland sinus
Teat sinus |
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What is the purpose of the subcutaneous venous plexus?
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Erectile tissue - regulates milk let down and swells, allowing young to stay on teat
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What is the teat canal/papillary duct closed by?
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Smooth muscle sphincter and elastic tissue
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What type of epithelium is present in the teat canal?
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Stratified squamous
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How is the fatty plug formed?
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Desquamation of epithelia and fatty secretions
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What is the function of the fatty plug?
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Provides a physical block against bacterial entry as well as bactericidal properties
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What are 3 functions of the teat?
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Provides prehensile structure for offspring to grab with conducting channel
Prevents leakage between nursing periods Provides sensory input for milk ejection reflex by suckling stimulus |
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Which arteries supply the udder?
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External pudendal artery - from external iliac artery
Ventral perineal artery - Internal iliac artery |
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Why does the external pudendal artery form a flexure as it enters the udder?
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To protect against stretching
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Which arteries form the cranial and caudal mammary arteries?
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Cranial mammary arteries - external pudendal
Caudal mammary arteries - ventral perineal |
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Which veins drain the udders?
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External and internal pudendal veins -> caudal vena cava
Cranial and caudal epigastric veins -> anastamose into subcutaneous abdominal milk vein -> cranial vena cava |
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Describe the innervation of the udder
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Genitofemoral nerve - gland substance and deeper parts of teat wall, sympathetic supply to smooth muscle and blood vessels
Cranial skin - 1st and 2nd lumbar nerves Middle skin - genitofemoral n. Caudal skin - mammary branches of pudendal n. NO PARASYMPATHETIC SUPPLY |
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Describe the lateral suspensory lamina
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Fibrous CT
Originates from external inguinal ring (cranially) Symphyseal tendon (caudally) |
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Describe the medial suspensory lamina
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Elastic CT
Originates from tunica flava - fascia of external abdominal oblique m. (cranially) Symphyseal tendon (caudally) |
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What does the lateral lamina protect?
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Mammary vessels and superficial inguinal lymph nodes
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What do the lamina give off?
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Numerous oblique lamellae
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Describe the first stage of mammogenesis - before birth
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Ectodermal proliferation -> mammary buds
Invagination into mesodermal fat pad -> teats Primary sprouts -> teat and gland sinuses (galactophores) Secondary sprouts -> lactiferous ducts |
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Describe stage 2 of mammogenesis - from brith to pregnancy
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Isometric growth up to 3 months
Allometric growth after 3 months At puberty (8-17m) hormones affect growth Oestrogen -> duct lengthening and branching Progesterone -> duct development and enlargement Returns to isometric growth at 30-36 months |
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Describe stage 3 of mammogenesis - pregnancy
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Exponential (allometric) growth due to oestrogen, progesterone and prolactin
Fatty pad replaced by ducts, alveoli, CT and bvs. Latter stage, majority of growth due to secretions accumulating in alveoli |
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Describe stage 4 of mammogenesis - lactation
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Growth continues until around 30 days (peak milk production) then a gradual loss of secretory cell occurs
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