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Flashcards in endocrine embryology Deck (25):

common component of all endocrine organs

mesodermal component which gives rise to vasculature


what gives rise to brain and spinal cord

neural ectoderm


what gives rise to the mouth

ectoderm- comprises the tissues as far back as the pharynx (the pharynx is endodermal origin) in th upper mouth. In lower mouth, ectoderm gives rise to tissues half way along the length of the tongue.


define stomodeum

mouth opening


origin of posterior pituitary

neural ectoderm evaginates at 4 weeks forming the posterior pituitary and central portion of infundibular stalk, plus the median eminence


origin of anterior pituitary

At 4 weeks, oral ectoderm from upper part of mouth evaginates forming rathkes pouch, and comes in contact with neural ectoderm. This pouch pinches off from oral epithelium and develops into anterior pituitary. The


Origin of the sella turcica

connective tissue which develops around the pituitary


origin of pituitary vasculature

local mesoderm infiltrates the pituitary giving rise to hypophyseal portal system and small vessels in posterior pituitary


Be able to describe the origins ofthe pars distalis, pars intermedia, pars tuberalis, pars nervosa and infundibular stalk.

pars tuberalis, intermedia and distalis are from oral ectoderm. Pars nervosa and infundibular stalk are from neural ectoderm


origin of thyroid follicle epithelial cells



origin of calcitonin secreting cells in thyroid

neural crest- originally ectodermal


origing of thyroid vasculature



origin of parathyroid glandular cells

endoderm- inferior parathyroids from cleft btw 3rd and 4th pharyngeal pouches. Superior parathyroids from cleft after 4th pharyngeal pouch


describe thyroid gland formation

Medial evagination of endoderm btw first and second pharyngeal pouches forms (thyroid diverticulum) > the diverticulum enlarges and descends in the pharynx connected via the thyroglossal duct > the thyroid descends until in front of trachea > thyroglossal duct degenerates


what is the ultimobranchial body

group of cells that form just below the 4th pharyngeal pouch which gets populated by neural crest derived cells and cells that give rise to calcitonin secreting cells of thyroid.


How does the parathyroid and calcitonin cells become integrated into the thyroid

During the thyroids descent, it comes in contact with primordia of parathryoids and the ultimobranchial body, which both become embedded in the thyoid resulting in parathyroids and calcitonin releasing cells respectively


How does the cellular composition of the thyroid change

initially it is a solid mass of endodermal cells, but these get interspersed by infiltrating mesoderm into cords of cells (which will become follicular cells) then to small clumps which then form the epithelia of follicles


origin of adrenal cortex and medulla

Cortex arises from mesoderm (mesothelium between the dorsal mesentery and urogenital ridge) and medulla arises from ectoderm


Another name for urogenital ridge

wolffian body


describe development of the adrenal cortex

At 4 weeks, mesonephric or wolffian duct induces cells in the cleft btw dorsal mesentery and urogenital ridge to migrate into the mesenchyme dorsal to it > They form a cup structure > at 2-3 months another wave of clls from coelomic epithelium (mesothelium) enter the mesenchyme and surround the outer part of the cup


origin of the layers of the cortex

Reticularis: first round of cells that arrive from the coelomic epithelium. Fasciculata and glomerulosa: second group of cells that arrive from coelomic epithelium.


How does the adrenal cortex change after birth

a portion of the inner region of the early reticularis regresses. The layers of the fasciculata and glomerulosa become more distinct


development of adrenal medulla

Neural crest cells migrate to become sympathetic ganglia (sympathogonia) and some of them then migrate into the center of the cup.


Chromaffin cells

The early progenitors of the epi and NE producing cells of the medulla which migrate from the neural crest. They stain yellow brown with chrome salts


how does the adrenal medulla change after birth

It increases in volume.