Endocrine Development Flashcards
All endocrine organs will have a ______ component that gives rise to vasculature. But not all will arise from ______.
Mesoderm
Endoderm
Early in development, the neural tube and primitive brain arise from ______. And will become our ______/
neural ectoderm (ectoderm infolding that pinches off)
will become brain and spinal cord
_____, a tubular arrangement of cells, gives rise to the majority of the digestive system.
Endoderm
What gives rise to the upper part of the mouth back to the pharynx?
Ectoderm (which comprises the stomodeum - mouth opening)
- *note: pharynx is endodermal in origin and fuses with the ectoderm of the stomodeum
- ectoderm also gives rise to tissues halfway along length of tongue
At what week does the primitive diencephalon form the beginning of the posterior pituitary and central portion of the infundibular stalk? How?
at 4 weeks
An EVAGination of the lower part of the neural ectoderm of the primitive diencephalon forms the beginnings of the posterior pituitary and central portion of the infundibular stalk.
Rathke’s pouch
Oral ectoderm from the upper part of the mouth that evaginates (upward) and comes into contact with the neural ectoderm.
The anterior pituitary develops from the original oral ectoderm after it buds off and connects to neural ectoderm.
(remember we said the neural ectoderm forms the beginnings of the posterior pituitary and infundibular stalk)
- The pars distalis, intermedia, and tuberalis are all derived from rathke’s pouch
Which time period does the pituitary take on a more typical shape of the gland?
3rd month
Local mesoderm infiltrates the glandular/nervous tissue of the pituitary, giving rise to the ______
vasculature of the hypophyseal portal system and small vessels in the posterior pituitary.
Embryologic cellular components of the thyroid
- Endoderm
- thyroid follicle epithelial cell - Neural crest
- originally ectodermal
- calcitonin secreting cells - Mesodermal
- vasculature
All become embedded in the thyroid, but originate from different locations along the developing pharynx
Thyroid development begins as?
Begins as medial EVAGination of the endoderm called the thyroid diverticulum
- begins to extend ~ between 1st and 2nd pharyngeal pouches
Parathyroid development
Develop from cells INSIDE cleft between 3rd and 4th pouches, called the inferior parathyroid
and
From cells INSIDE cleft after the 4th pouch, called superior parathyroids
Ultimobranchial body
- derived from
- gives rise to
derived from group of cells found in cleft after 4th pharyngeal pouch
(diff from superior parathyroids)
Gives rise to calcitonin-secreting or parafollicular cells of the thyroid.
As the thyroid diverticulum enlarges and descends along the pharynx, it is attached via the _______. This structure typically degenerates, but _______ can develop if portions of it remains.
Thyroglossal duct
Thyroglossal cysts
can develop, or
thyroid may fail to descend properly.
During the descent of the thryoid, it comes in contact with the primordia of the parathyroids that arise from the clefts between the ____ and ____ pharyngeal pouches, as well as the ______ body. These become embedded in the thyroid normally.
3rd and 4th
Ultimobranchial body
Initially, the thyroid is a solid mass of _____ cells, but they get interspersed by infiltrating _____, that give rise to the vasculature that encircles each follicle.
Endodermal cells
Infiltrating mesoderm
Origin of cortex vs medulla
Cortex: mesoderm
Medulla: ectoderm
The initial primordium of the cortex originates from what? Describe the development of the cortex of the adrenal glands.
a group of cells of the coelomic epithelium (mesothelium) in a cleft btwn the region of the gut and the urogenital ridge.
4 weeks: cells of the coelomic epithelium proliferate and migrate into the mesenchyme just dorsal to it –> multiply and organize into cortex of the adrenal gland.
- reticularis of cortex
2-3 months: cells again proliferate from the coelomic epithelium at the same location and enter the mesenchyme (again) and surround the outer part of the cup
- fasciculata and glomerulosa
(cortex entirely mesodermal in origin)
Describe the development of the medulla of the adrenal glands.
Neural crest cells (ectoderm) migrate to a region that become the sympathogonia (ultimately the sympathetic ganglia)
Some sympathogonia migrate to the center and becomes the medulary region of the adrenal gland.
Stains yellow-brown with chrome salts (chromaffin cells)
Chromaffin cells
stains yellow brown with chrome salts
are the progenitors of epi and norepi cells of the medulla.
