ADRENAL GLAND

Izatty LimBatch 4 (0308188)

5th September 2014

HISTOLOGICAL STRUCTURE

CORRELATION WITH FUNCTION

OVERALL ADRENAL GLANDADRENAL GLAND

Covered with thick CT capsule from which trabeculae extend into parenchyma, carrying blood vessels & nerves

OUTER YELLOWISH CORTEX- Steroid- secreting- 90% of the gland by weight- Mesodermal mesenchyme- Controlled in part by anterior pituitary gland- Regulate metabolism & maintain normal electrolyte balance

ZONA GLOMERULOSA

mineralocorticoids

ZONA FASICULATA

glucocorticoids

ZONA RETICULARIS

androgens

DARK INNER MEDULLA

- Catecholamine-secreting- Form center of the gland- Neuroectoderm- Richly innervated by preganglionic sympathetic fibers

CHROMAFFIN CELLS

catecholamines

SYMPATHETIC GANGLION CELLS

Cortex

Zona glomerulosa mineralocorticoids (aldosterone)

Zona fasiculata glucocorticoids (cortisol)

Zona reticularis Androgens (dehydroepiandosterone(DHEA))

Medulla catecholamines (epinephrine & norepinephrine)

ADRENAL CORTEX HISTOLOGY

• Cells arranged into three concentric zones– differentiated based on the pattern produced by cords of cells– boundaries between zones are indistinct

ZONA GLOMERULOSA: narrow outer zone that constitutes up to 15% of the cortical volume

ZONA FASICULATA: thick middle zone that constitutes nearly 80% of the cortical volume

ZONA RETICULARIS: inner zone that constitutes only 5% to 7% of the cortical volume but is thicker than the glomerulosa because of its more central location

ZONA GLOMERULOSA

• small columnar cells• arranged in closely packed ovoid clusters & curved columns• spherical nuclei appear closely packed and stain densely

• rich network of fenestrated sinusoidal capillaries surrounds each cell cluster

• lipid droplets are sparse

• SECRETES MINERALOCORTICOIDS (ALDOSTERONE, DEOXYCORTICOSTERONE)– Maintain fluid & electrolyte balance

ZONA FASICULATA

• large polyhedral cells• arranged in long straight cords, one or two cells thick, separated

by sinusoidal capillaries• lightly staining spherical nucleus• Binucleate cells are common • numerous lipid droplets

– contain neutral fats, fatty acids, cholesterol, & phospholipids (precursors for the steroid hormones)

• SECRETES GLUCOCORTICOIDS (CORTISOL, CORTICOSTERONE)– Regulate metabolism of carbohydrate, protein & lipid (gluconeogenesis, proteolysis, lipolysis)– Suppress inflammation & immune response– Impair healing process

ZONA RETICULARIS

• dark acidophilic cells– abundant lipofuscin pigment granules

• Smaller cells compared to cells in zona fasciculata, nuclei are more deeply stained– less cytoplasm; thus the nuclei appear more closely packed.

• arranged in anastomosing cords, separated by fenestrated capillaries• cells have relatively few lipid droplets

• SECRETES ANDROGENS (DEHYDROEPIANDOSTERONE, ANDROSTENEDIONE)– Weak masculinizing effect– Libido, body hair (female)

ADRENAL MEDULLA HISTOLOGY• Consist of:

– Chromaffin cell (most abundant cell) – CT– Sinusoidal blood capilaries– Nerves

• Myelinated– Sympathetic ganglion cells

• round or polygonal with prominent nuclei• May be in cluster

CHROMAFFIN CELL

• Pheochromocytes

• Large, pale-staining epithelioid cells

• Organized in ovoid clusters & short interconnecting cords

• Intimate relation with blood capillaries

• Granular cytoplasm due to hormone-containing granules can be observed– Stain intensely with Chromaffin salts

• SECRETES CATECHOLAMINES (ADRENALINE, NORADRENALINE)– Augment sympathetic system activity– Major role in acute response to stress

Chromaffin cells arranged in clusters, usually around medullary veins

Ganglion cells (round or polygonal with

prominent nuclei)

CLINICAL IMPORTANCE

• Excessive cortical secretion– Cushing’s syndrome hypercortisolism– Masculinization (virilism) excessive adrogens in women– Feminization excessive estrogens in men– Adrenogenital syndrome excessive sex hormone in children

• Insufficient cortical secretion– Addison’s disease

CLINICAL IMPORTANCE• Abnormal medullary secretion

– Hyposecretion• Not much problem if sympathetic function is normal• Some attenuation of acute response to stress

– Hypersecretion• Pheochromocytoma benign tumours of adrenal medulla

The tumor cells in pheochromocytoma may be arranged in alveolar (nesting), trabecular, solid/diffuse, or mixed patterns. Alveolar pattern is shown here

THANK YOU

REFERENCES• Histology of adrenal gland

– http://arbl.cvmbs.colostate.edu/hbooks/pathphys/endocrine/adrenal/histo_overview.html• Histology: A Text and Atlas

by Ross M.H. and Pawlina W.– https://

www.inkling.com/read/histology-michael-ross-and-wojciech-pawlina-6th/chapter-21/adrenal-glands#4652fc36484946c9a323b2baa04cd87b

• DiFiore's Atlas of Histology with Functional CorrelationsBy Victor P. Eroschenko, Mariano S. H. di Fiore– http://books.google.com.my/books?

id=sH87M12QswcC&pg=PA463&lpg=PA463&dq=histological+structure+adrenal+gland%27s+correlation+with+function&source=bl&ots=zP80SNqbej&sig=Cxhx-znWfbs0TdVCSrUFGTdCxBk&hl=en&sa=X&ei=LJwAVOapO5CcugSGuoLQDg&redir_esc=y#v=onepage&q=histological%20structure%20adrenal%20gland's%20correlation%20with%20function&f=false

• Adrenal Medulla Development Movie– http://

embryology.med.unsw.edu.au/embryology/index.php?title=Adrenal_Medulla_Development_Movie