Endocrine Glands II Adrenal glands
Prof Menna Abdel-Dayem
Adrenal Glands Suprarenal (Adrenal) Glands
● Two endocrine glands in contact with upper border of both kidneys. ● Derived from 2 embryonic sources: the mesoderm gives rise to adrenal cortex & neuroectoderm gives rise to adrenal medulla. Suprarenal (Adrenal) Glands Suprarenal (Adrenal) Glands
Stroma: Capsule, trabeculae and reticular framework Parenchyma: Cortex Medulla Suprarenal (Adrenal) Glands
Stroma:
Capsule: thick, covered with adipose C.T.
Trabeculae: thin, descend from the capsule to divide the cortex into compartments.
Reticular framework
Adrenal Cortex Zona Glomerulosa Zona fasciculata Zona Reticularis Suprarenal (Adrenal) Cortex
1-Zona Glomerulosa 2-Zona Fasciculata 3-Zona Reticularis
The narrowest zone. -The widest zone. -The deepest zone. just under the capsule -Polyhedral cells arranged in narrow & -Polyhedral cells arranged in branching & -Columnar cells straight cords anastomosing cords arranged in arched groups (glomeruli) (fascicles)separated by separated by blood sinusoids. surrounded by fenestrated capillaries fenestrated capillaries L.M. L.M. L.M. -Columnar cells with Polyhedral cells with central rounded pale Polyhedral cells with central rounded nuclei basal rounded nuclei vesicular nuclei . & acidophilic cytoplasm & pale cytoplasm Some cells are binucleated with acidophilic vacuolated cytoplasm ,so called Spongiocytes.
Suprarenal (Adrenal) Cortex
1-Zona Glomerulosa 2-Zona Fasciculata 3-Zona Reticularis
E.M. E.M. E.M. Rich in mitochondria, Rich in mitochondria, Rich in mitochondria, G.A., sER & G.A., sER & few fat droplets G.A., s-ER, many fat droplets, few fat droplets. Lipofuscin cholesterol & vitamin C pigment (androgens) is commonly seen Function: Function: Function: Secrete mineralocorticoids Secrete glucocorticoids (cortisol) that Secrete androgen & small amount of
mainly Aldosterone which regulate H2O & regulate lipid, protein& CHO glucocorticoids Electrolyte balance metabolism. Have an anti- (under control of inflammatory & immuno- suppressive angiotensin II) action. (under control of ACTH) (under control of ACTH)
Adrenal Medulla
Adrenal Medulla
1. Chromaffin cells: – Modified sympathetic neurons that have lost their processes and became secretory cells. – Polyhedral cells arranged in branching cords separated by blood sinusoids. – Have basophilic cytoplasm rich in fine granules that stain brown with chromium salts & central rounded pale nuclei. Adrenal Medulla enkephalins. = peptides opiate-like contain also granules The secretory granules dense more with cells: secreting Noradrenalin the membrane. beneath halo clear peripheral and & dense less with cells: secreting Adrenalin b) level: at 2 types ofultrastructural are cells There the granules. i.e. fill the contents granules, homogeneous a) Golgi developed well mitochondria, shows Cytoplasm • granules. secretory rER & membrane-bound apparatus, • EM: 1 Chromaffin cells: . Adrenal Medulla
2. Sympathetic nerve cells: - Stellate nerve cells scattered between chromaffin cells to stimulate their secretory activity. Innervated by preganglionic sympathetic nerve fibers. Functions of the Adrenal Medulla
• Secrete adrenalin (epinephrine) & noradrenalin (norepinephrine) in response to stress (fight, flight & fright).
• During normal activity, the medulla continuously secretes small amounts of the 2 hormones. Migrated sympathetic ganglion: 1- Innervation ………. 2- Embryologic origin ………… 3- contain ………… Paraganglia
Masses of chromaffin cells scattered in close association with the sympathetic ganglia. They develop from neuroectoderm (like sympathetic ganglia). Give +ve chromaffin reaction. Function: secrete adrenalin & noradrenalin and enkephalins Blood Supply
Three suprarenal arteries (superior, middle & inferior) pierce the capsule →
3 groups of arterioles (capsular, cortical & medullary). The cortical capillaries drain into veins of medulla which join to form suprarenal vein that leave the gland
Cortex and Medulla
Cortex Medulla
Mesodermal in origin Ectodermal
Formed of 3 zones (glomerulosa, fasciculate & Two types of cells (chromaffin& nerve cells) reticularis) Essential to life (corticosteroids) Less essential
Secretes mineralocorticoids, glucocorticoids & Secretes adrenalin, noradrenalin & enkephalins sex hormones Give –ve chromaffin reaction +ve reaction
Supplied with arterial blood Supplied with arterial & venous blood