ZOO 3713C Lecture Notes - Lecture 11: Supernumerary Nipple, Lactiferous Duct, Inverted Nipple
Document Summary
Holocrine secretion cells fill up and explode. Sebaceous gland: buds from the sides of developing hair follicles, not all hair some hairs lacks sebaceous glands, branches to form several alveoli and ducts, sebum oily lubricant, stem cells renew secretory cells. Eccrine secretion directly across plasma membrane. Bud coils at tip to form secretory portion. Secretory cells differentiate from cells lining duct. Milk lines two bands of ectodermal thickenings. Cranial to caudal ventrolateral body wall. Week 5- primary bud = thickening of epidermal cells from ridge. Two mesodermal components: fibroblastic cells controls branching pattern, fatty cells controls shape of duct system. Week 10-12 branching to form many secondary buds: secondary buds lengthen and branch. Birth 15-25 lactiferous ducts that open into mammary pit (external opening) Mesodermal proliferation -> areola and protruding nipple (lack of proliferation inverted nipple) Teeth 2 sets from primary dentition (deciduous or milk teeth) and secondary dentition (permanent teeth).
