Adrenal Gland Histology Flashcards
What does the cortex of the adrenal gland originate from?
Mesodermal
Develops from celomic epithelium of the posterior abdominal wall
What does the medulla of the adrenal gland originate from?
Ectodermal
Develops from neural crest cells
By the eight week of fetal development, the cortical elements have differentiated into what?
Thin outer definitive cortex and a thicker inner fetal cortexx
What does the fetal cortex actively produce?
fetal steroids during gestation but involutes rapidly after birth
What are adrenocortical rests?
Occur in up to 50% of newborn infants
Tend to atrophy and disappear early postpartum period
Can be found along path of embryonic migration of adrenal cortex
Describe accessory adrenocortical nodules
minor developmental anomalies arising from partly or completely detached rests of the coelomic epithelial primordia from which the adrenal cortex is derived
Most frequently located in contact with the capsule at one pole of adrenal but can occur completely separated in the retroperitoneal fat
Describe the development of adrenal zones
occurs slowly after birth, in parallel with regression of fetal cortex
Distinct zonae glomerulosa and fasiculata present at birth
Zona reticularis develops during the first year of life
medullary elements, derived from __________, migrate forward to ________ and paravertebral regions and along the adrenal vein toward the medial aspect of the developing ___________.
Neural crests
para-aortic
adrenal fetal cortex
During the early stage of gestation, the adrenal cortex synthesizes ____________, a precursor of the synthesis of estrogen by the _________.
dehydroepiandrosterone (DHEA)
Placenta
A lack of ________________ activity prevents the synthesis of progesterone, glucocorticoids and androstenedione
3 beta-hydroxysteroid dehydrogenase (3B-HSD)
The interactions between the fetal adrenal cortex and the placenta is known as the __________.
fetoplacental unit
3B-HSD Congenital adrenal hyperplasia is an __________ form of CAH. It results from a mutation in the gene for ___________.
uncommon
3 beta- HSD type II
What are the clinical presentations of 3 beta- HSD CAH?
Incomplete loss of 3 beta - HSD Type II
Virilization of genetically female infants and undervirilization of genetically male infants
3B - HSD CAH is a form of ______ hypoadrenalism, and is the the only form of CAH that can cause___________ in both genetic sexes.
primary
Ambiguous genitalia
During pregnancy, what are the sources of glucocorticoids for the fetus?
either of maternal origin or synthesized from placental progesterone by the fetus
What are the three main developmental events that require glucocorticoids?
- production of surfactant by type II alveolar cells after eight month of fetal life
- development of functional hypothalamopituitary axis
- induction of thymic involution
Each gland consists of a _____ outer cortex (__%) and a _____ inner medulla (__%)
Yellowish
80-90%
Reddish
10-20%
The adrenal cortex is of _______ origin and produces ______.
mesodermal
steroid hormones
The adrenal medulla is of ________ origin and produces __________.
Neuroectodermic
Catecholamines
The adrenal cortex consists of three concentric zones:
- outermost layer of the cortex: zona glomerulosa
- middle layer: zona fasiculata
- innermost: zona reticularis
What does the zona glomerulosa produce and to what stimulus ?
mineralocorticoids, mainly aldosterone
in response to Angiotensin II also ACTH
Describe the histology of zona glomerulosa
lies under capsule and is 10-15% of cortex
cells aggregate into glomerulus-like arrangement and have a moderate amount of lipid droplets in the cytoplasm
Zona glomerulosa lacks the enzyme ___________, cant produce sex steroids or _______.
17alpha-hydroxylase (CYP17)
cortisol
Aldosterone stimulates the retention of ____, ______ in kidneys, and renal secretion of ____ and _____.
Na, H2O
K and H
What does the zona fasiculata secrete?
glucocorticoids and androgens