Adrenal and Pancreas Histology Flashcards
What is the gross structure of the adrenal glands?
Paired retroperitoneal structures. Two distinct parts (structurally and functionally). Thick connective tissue capsule.
What are the two distinct parts of the adrenal gland?
Cortex (mesodermally derived), Medulla (neural crest derived
What is the innervation of the adrenal glands?
Sympathetic. Most fibers end in medulla as preganglionic sympathetics on medulla chromatin cells.
What are the three layers of the adrenal cortex?
Zona glomerulosa (narrow), Zona fasiculata (broadest), Zona reticularis (narrow)
What is the adrenal cortex derived from? What does it produce?
Mesoderm. Produces steroid hormones.
What is the Zona glomerulosa?
Narrow outer zone inside the capsule. Cells in ovoid groups or cords. Rich capillary network. Secretes mineralocorticoids.
What mineralocorticoids does the zona glomerulosa release?
Aldosterone, Deoxycorticosterone
What cells are present in the zona glomerulosa?
Round, basophilic nuclei, eosinophilic cytoplasm. Abundant smooth ER, sparse lipid content.
What is the Zona fasiculata?
Broadest and middle zone of cortex. Cells in parallel cords radiating towards medulla. (Cords of cells surrounding by longitudinal meshwork of sinusoidal capillaries)
What cells are present in the Zona Fasiculata?
Cells (spongiocytes - due to many lipid droplets). Cuboidal or polyhedral. Abundant lipid droplets. Lightly stained cytosol. Abundant smooth ER.
What does the Zona Fasiculata secrete?
Glucocorticoid
What types of glucocorticoid doe the zona fasiculata secrete?
Cortisol or hydrocortisone. Some androgens and very little estrogens also produced.
What is the Zona Reticularis?
Innermost zone of cortex. (Irregular cords of cells form an anastomosing network)
What are the cells like in the Zona Reticularis?
Few lipid droplets. Abundant smooth ER. Light and dark cells (dark cells probably degenerative).
What do cells of the Zona Reticularis produce?
Sex steroid. Primarily androgens, very little estrogens, some glucocorticoids also.
What is the adrenal medulla made up of?
Chromaffin cells surrounded by capillaries and venules.
What are characteristics of the adrenal medulla cells?
Columnar, ovoid, or polyhedral. Non-regenerative. Prominent Golgi and rough ER. Small secretory granules (EPI and NE (catecholamines), Chromogranins, ATP, soluble proteins)
What are Chromaffin cells?
Regarded as modified post-ganglionic sympathetic neurons. Lack axons or dendrites. Neural crest origin. Innervated by pre-ganglionic sympathetics. Secrete directly into capillaries (instead of nerve terminals)
What are Pheochromocytomase?
Tumors of adrenal medulla.
What is the blood supply to the adrenal gland?
3 arteries supply each adrenal (suprarenal arteries). Subcapsular plexus.
How does the venous system of the adrenal medulla work?
Medullary venules unite to form larger collecting veins, join the medullary central vein and the suprarenal vein.
What is the subcapsular plexus?
3 sets of capillaries. Capsular plexus, empty into capsular veins. Cortical sinusoidal (fenestrated) vessels, drain into venules of medulla. Medullary capillaries (fenestrated), drain into venules of medulla.
What is the Pancreatic Islet Structure?
Spheroidal masses. 1 x 10to6 islets/gland. 3,000 cells/islet. Cells arranged in irregular cords. Surrounded by acini of exocrine pancreas or found in interlobular connective tissue. More in tail of pancreas than in head.
What do Chromaffin cells secrete?
Either NE or EPI, not both! Each cell secretes just one
