- Heart, lungs, kidney, GI tract, placenta

Organs with endocrine function

- formed from cranial outpocketing of diencephalon

- integrates light-dark cycles (circadian rhythm)

- melatonin = active hormone

- "jet lag" response

- 8 wks body --> 4 months gland

Pineal Gland

- 2 tissue origin (diencephalon/stomodeum)

- also called hypophysis

- secretes "releasing" hormones, oxytocin, ADH

Pituitary Gland

- neurohypophysis = infundibulum

- ADH/oxytocin

- diencephalic origin

Posterior Pituitary

- stomodeum origin from Rathke's pouch (4th week)

- remnants can transform into tumor (craniopharyngioma)

- Adenohypophysis

Anterior Pituitary

- 2 tissues combine (proper + parafollicular)

- fetal function around 3 months (thyroxin) --> important for fetal growth and development (brain)

- deficiency leads to cretinism

Thyroid

- mesodermal epithelium

- endodermal proliferation between tubercum impar and copula

- thyroglossal duct (midline descent)

- remnant surface structure = foramen cecum

Thyroid proper

- migrate from pharyngeal pouch 4/5 (ultimobranchial body)

- release calcitonin (decrease blood calcium)

- works against PTH

Parafollicular cells (C cells)

- origin of thymus and inferior parathyroid migration

3rd pharyngeal pouch

- origin of superior parathyroid migration

4th pharyngeal pouch

- originates at 4/5th pouch

- c-cells migrate into thyroid and reside around follicles

Ultimobranchial body

- derived from mesoderm associated with septum transversum (not kidney)

- islands of cortical cells coalesce

- neural crest cells migrate in small clusters into center of gland thru cortex

- neuroblastoma can occur from neural crest clusters

Adrenal Gland

- dorsal and ventral (left and right) buds form exocrine portion

- endocrine form from central glands (Ngn3) --> islet cells

- Wirsung and Santorini ducts fuse

- ventral bud rotates 270 degrees

Pancreas

- hormones produced from stromal and epithelial derivatives

- Male - Leydig --> testosterone

- Female - thecal --> androstenedione, granulosa --(converts to)--> estrogens/progesterone

- Prostate converts T --> DHT

Gonads

- yellow, large clear cells

- stain for Oil Red- O (Lipid)

Steroid hormone producing cells