012915 endocrine devo Flashcards
compare development of endocrine vs exocrine glands
exocrine: from the epithelium, an epithelial bud grows and extends into the underlying mesenchyme. the center of the epithelial bud becomes hollow to form the duct.
endocrine: from epithelium, an epithelial bud grows and extends into mesenchyme. the continuity in the epithelial bud is lost. portion goes on to become secretory cells of endocrine gland with blood vessels
what are the precursors of the pituitary gland
hypophysial diverticulum/Rathke’s pouch (grows up from roof of oral cavity)
neurohypophysial diverticulum/infundibulum of diencephalon (grows down from floor of forebrain)
both are ectoderm
what is the infundibulum
median eminence and pituitary stalk and neural lobe
how does thyroid gland form?
as midline diverticulum from floor of pharynx–it moves down and eventually the thyroglossal duct (which extends from the foramen cecum) disappears
what comes from pharyngeal pouches 3 and 4 in the pharynx?
from 3: dorsal-becomes inferior parathyroid glands. ventral-becomes thymus
from 4: dorsal-becomes superior parathyroid glands. ventral-becomes neural crest/ultimopharyngeal bodies that become C cells
from what are thyroid follicular cells derived?
thyroid diverticulum (endoderm) from floor of pharynx
from what are parafollicular cells derived?
neural crest from ultimopharyngeal bodies
from what are parathyroid gland principal cells derived?
dorsal wing of pharyngeal pouches 3 and 4 (endoderm)
where does thyroid begin development?
foramen cecum of tongue
when does development of thyroid gland begin?
wk 4 (stops by wk 7)
cortical cells of adrenal gland are derived from what?
from primary and secondary waves of cells that originate from COELOMIC EPITHELIUM adjacent to forming gonad (so cortex comes from mesoderm)
primary wave is the fetal adrenal cortex
secondary wave is the definitive adrenal cortex
how does adrenal gland develop?
coelomic epithelium proliferates and produces cells that go to underlying mesenchyme (2 waves of cells). also, migrating neural crest cells are chromaffin cell precursors
which endocrine glands have neural crest cells
adrenal
thyroid
how does pineal gland develop?
it’s associated with the diencephalon and comes off the roof of diencephalon
what do each of the following come from (ectoderm, mesoderm or endoderm)–pituitary, thyroid, parathyroid, adrenal
pituitary-primarily ectoderm
thyroid-primary endoderm with neural crest C cells
parathyroid-purely endoderm
adrenal gland-primarily mesoderm except medulla is neural crest
