devt of mammary glands Flashcards
Present in both sexes initially (axillary to inguinal line)
milk ridges
milk ridges
In humans, only the _________ remains.
In ruminants, only the ________ remains.
axillary portion
inguinal area
in this tissue,
Epidermis forms ducts due to specific dermal influence.
Extensive branching occurs during puberty.
normal female tissue
this causes regression of ductal ingrowth and branching during a specific developmental window (male phenotype).
absence leads to the female phenotype.
testosterone
hormonal inflences (6)
Puberty: Mesoderm under fat pads induces further branching.
Pregnancy: Extensive branching for milk production.
Prolactin: Promotes milk secretion in alveoli.
Baby suckling: Increases milk production.
Oxytocin: Triggers milk release by contracting myoepithelial cells.
Negative feedback loop: High milk production suppresses ovulation.
Epithelial-Mesenchymal Interaction
Epithelium and dermis interact to influence each other’s development.
Experiments:
Normal ectoderm + TFM mesoderm with testosterone: Female phenotype.
TFM ectoderm + normal mesoderm: Male phenotype.
dermis origin
- dermatome
- somitomeres
- neural crest
- lateral plate mesoderm
contribution to body wall.
Segments of the somite.
Contributes to pigment cells, bone, etc.
contributes to muscle, connective tissue, etc
neural crest cell fate depends on the __________ except for _________________
environment
cardian neural cells
migration patterns of neural crest cell (2)
Dorsal migration (trunk)
Ventromedial migration (trunk)
derivatives of neural crest cell (4)
Cranial: Facial bones, cartilage, ganglia
Trunk: Skin pigment cells, Schwann cells, etc.
Vagal and sacral: Parasympathetic nervous system
Cardiac: Contribute to heart development
regulatory molecules (2)
Stimulatory: Fibronectin, laminin (promote migration)
Inhibitory: Ephrin (e.g., restricts posterior sclerotome migration)
