Endocrine Histology

Front 1

Describe the nerve terminals in the pars nervosa, and compare the structure and fxn of herring bodies with pituicytes

Back 1

Pars Nervosa: the distal terminals of the axons of the hypothalamohypophyseal tract end in the pars nervosa. these axons are produced by pituicytes. they contain vasopressin and oxytocin.
Herring bodies: accumulations of neurosecretory granules along the length of the axon and at the terminal. In response to accumulation, the neurosecretory granules are released into the perivascular space.
Pituicytes: ensheath axons of the pars nervosa

Front 2

Describe the blood supply of the Pituitary gland:

Back 2

the hypothalamus and pit are linked by the hypothalamic-hypophyseal portal blood vessels. the arteries of the anterior pit arise from the internal carotids as inferior and superior hypophyseal arteries. the superior supply the hypothalamus.

Front 3

Contrast the pars tuberalis and inundibular stalk in terms of cellular composition and embryonic origin

Back 3

Pars tuberalis: part of anterior pituitary. originates from rathke's pouch. from Oral Ectoderm. Cuboidal to low columnar epithelium. Basophilic cells
Indfundibular stalk: Posterior pituitary. comes from infundibulum, from neural ectoderm, composed of axons and pituicytes

Front 4

Describe the Zona glomerulosa in terms of its origin, characteristics, horomones secreted, control, and fxn

Back 4

Comes from mesoderm
is the outermost layer. has small columnar cells arranged in cords/clusters. lipid droplets found in cytoplasm. produces Aldosterone and deoxycorticosterone. alters fxns of renal tubules. targets DCT, gastric mucosa, sweat glands, salivary glands. Controlled by A2 and ACTH

Front 5

Describe the Zona Fasciculate in terms of its origin, characteristics, horomones secreted, control, and fxn

Back 5

Comes from mesoderm
Intermediate layer
Polyhedral shaped cells arranged in radial columns. Spongiocytes have round mitochondria. Secrete cortisol/corticosterone. Controls fat/carbohydrate metabolism. anabolic/catabolic effects. ACTH controlled. targets Bone,fat, muscle

Front 6

Describe the Zona Reticularis in terms of its origin, characteristics, horomones secreted, control, and fxn

Back 6

Comes from Mesoderm
Similar to spongiocytes but with fewer lipid droplets. Innermost layer. dark staining. Secretes androgens androsteindione, epiandrosterone. Weak Masculinizing hormones. ACTH controlled. intermediates in conversion of progestins to androgens and estrogens in muscle and adipose.

Front 7

Describe the adrenal medulla in terms of Embryologic origin, cell types, interaction between cell types, and regulation of its secretions

Back 7

Comes from Neuroectodermal Crest cells
Cell types: chromaffin cells, preganglionic sympathetic axons.
Interactions: axons synapse on chromaffin cells and release ACH, activating nicotinic receptors to release E/NE into circulation. Regulated by sympathetic NS.

Front 8

Describe what makes the thyroid gland unique among human endocrine glands and compare relative size of thyroid follicles with fxn

Back 8

Its unique b/c it stores large amounts of hormone in an inactive form within extracellular compartments in the center of follicles. Actively secreting thyroid tissue is characterized by smaller follicles lined with tall cuboidal/columnar cells. less active cells are flattened.

Front 9

How do you distinguish between the exocrine and endocrine pancreas?

Back 9

Exocrine is majority of gland. consists of acini which drain into a highly branched duct system. acinar cells are triangular shaped, with apices projecting towards a central lumen of a duct.
Endocrine tissue forms islets of langerhans. Pale staining

Front 10

Describe the main cell types of the parathyroid gland in terms of histology, FXN, and hormones secreted

Back 10

Chief cells: most numerous, small, round, light, synthesize PTH.
Oxyphilic cells: Acidophilic, nucleus is small, intense basophilic. Fxn unknown
Also transitional cells