Adrenal and Pancreas Histology

Question 1

What is the gross structure of the adrenal glands?

Answer 1

Paired retroperitoneal structures. Two distinct parts (structurally and functionally). Thick connective tissue capsule.

Question 2

What are the two distinct parts of the adrenal gland?

Answer 2

Cortex (mesodermally derived), Medulla (neural crest derived

Question 3

What is the innervation of the adrenal glands?

Answer 3

Sympathetic. Most fibers end in medulla as preganglionic sympathetics on medulla chromatin cells.

Question 4

What are the three layers of the adrenal cortex?

Answer 4

Zona glomerulosa (narrow), Zona fasiculata (broadest), Zona reticularis (narrow)

Question 5

What is the adrenal cortex derived from? What does it produce?

Answer 5

Mesoderm. Produces steroid hormones.

Question 6

What is the Zona glomerulosa?

Answer 6

Narrow outer zone inside the capsule. Cells in ovoid groups or cords. Rich capillary network. Secretes mineralocorticoids.

Question 7

What mineralocorticoids does the zona glomerulosa release?

Answer 7

Aldosterone, Deoxycorticosterone

Question 8

What cells are present in the zona glomerulosa?

Answer 8

Round, basophilic nuclei, eosinophilic cytoplasm. Abundant smooth ER, sparse lipid content.

Question 9

What is the Zona fasiculata?

Answer 9

Broadest and middle zone of cortex. Cells in parallel cords radiating towards medulla. (Cords of cells surrounding by longitudinal meshwork of sinusoidal capillaries)

Question 10

What cells are present in the Zona Fasiculata?

Answer 10

Cells (spongiocytes - due to many lipid droplets). Cuboidal or polyhedral. Abundant lipid droplets. Lightly stained cytosol. Abundant smooth ER.

Question 11

What does the Zona Fasiculata secrete?

Answer 11

Glucocorticoid

Question 12

What types of glucocorticoid doe the zona fasiculata secrete?

Answer 12

Cortisol or hydrocortisone. Some androgens and very little estrogens also produced.

Question 13

What is the Zona Reticularis?

Answer 13

Innermost zone of cortex. (Irregular cords of cells form an anastomosing network)

Question 14

What are the cells like in the Zona Reticularis?

Answer 14

Few lipid droplets. Abundant smooth ER. Light and dark cells (dark cells probably degenerative).

Question 15

What do cells of the Zona Reticularis produce?

Answer 15

Sex steroid. Primarily androgens, very little estrogens, some glucocorticoids also.

Question 16

What is the adrenal medulla made up of?

Answer 16

Chromaffin cells surrounded by capillaries and venules.

Question 17

What are characteristics of the adrenal medulla cells?

Answer 17

Columnar, ovoid, or polyhedral. Non-regenerative. Prominent Golgi and rough ER. Small secretory granules (EPI and NE (catecholamines), Chromogranins, ATP, soluble proteins)

Question 18

What are Chromaffin cells?

Answer 18

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)

Question 19

What are Pheochromocytomase?

Answer 19

Tumors of adrenal medulla.

Question 20

What is the blood supply to the adrenal gland?

Answer 20

3 arteries supply each adrenal (suprarenal arteries). Subcapsular plexus.

Question 21

How does the venous system of the adrenal medulla work?

Answer 21

Medullary venules unite to form larger collecting veins, join the medullary central vein and the suprarenal vein.

Question 22

What is the subcapsular plexus?

Answer 22

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.

Question 23

What is the Pancreatic Islet Structure?

Answer 23

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.

Question 24

What do Chromaffin cells secrete?

Answer 24

Either NE or EPI, not both! Each cell secretes just one

Question 25

What are the five pancreatic islet cell types?

Answer 25

Alpha (A) cells, Beta (B) cells, Delta (D) cells, Gamma (F or PP) cells, Epsilon (G) cells

Question 26

What are Alpha cells?

Answer 26

20 percent of islet cells. More numerous at periphery of islet. Secretory vesicles have a dense core.

Question 27

What do Alpha cells secrete?

Answer 27

Glucagon (polypeptide, raises blood sugar levels)

Question 28

What are Beta cells?

Answer 28

70 percent of islet cells. More numerous towards center of islet. Secretory vesicles have crystalline appearance.

Question 29

What do Beta cells secrete?

Answer 29

Insulin (protein, lowers blood sugar levels, destruction of beta cells: Diabetes mellitus)

Question 30

What are Delta cells?

Answer 30

Less than 10 percent of islet cells.

Question 31

What do Delta cells produce?

Answer 31

Somatostatin. (polypeptide, both paracrine and endocrine effects)

Question 32

What are the paracrine and endocrine effects of somatostatin?

Answer 32

Suppresses secretion of insulin and glucagon (via paracrine mech). Reduces contractions of alimentary tract and gall bladder smooth muscles (via endocrine mech).

Question 33

What are Gamma (F or PP) cells?

Answer 33

Small in number (about 1 percent) of PP cells/islet.

Question 34

What do Gamma cells produce?

Answer 34

Pancreatic polypeptide. (Inhibits enzymatic secretion from exocrine pancreas. Relaxes gall bladder resulting in decreased bile secretion)

Question 35

What is the innervation of the pancreatic islets?

Answer 35

Sympathetic and parasympathetic supply.

Question 36

What is the blood supply of the pancreatic islets?

Answer 36

Rich fenestrated capillary network.

Question 37

What is Corticotropin functioning as in the Adrenal Cortex?

Answer 37

More of a basal factor that is required for secretion of hormones from these areas.