Endocrine Histology Flashcards
What allows blood vessels near endocrine glands to better take up hormones?
Fenestrated endothelium.
6 common features of endocrine tissues?
Ductless Vascular Organized into blocks, plates, cords (?) Epithelial (usually) Polyhedral Numerous organelles
4 “patterns” i.e. tissue types of endocrine cells?
Epithelial
Mesenchymal
Neural
Individual cells
From what germ layers are most epithelial endocrine cells derived? What’s one exception?
From ectoderm or endoderm.
Adrenal cortex is exception, being from mesoderm.
Which endocrine cells are mesenchymal?
Gonadal endocrine cells that come from mesenchyme - Leydig, granulosa, and luteal cells.
Where do neural endocrine cells come from? Two examples?
They come from neural crest cells.
Posterior pituitary cells.
Adrenal medulla cells.
Examples of endocrine “individual cells”?
Enteroendocrine cells - those that make, e.g. somatostatin, gastrin.
Juxtaglomerular cells - renin.
Where do the two parts of the pituitary come from?
Anterior: From roof of oropharynx, “buccal mucosa,” “Rathke’s pouch”.
Posterior: From neuroectoderm of floor of the 3rd ventricle.
6 hormones made by the ant. pit.?
GH, prolactin, FSH, LH, TSH, and ACTH.
2 hormones made by the post. pit.?
ADH / vasopressin.
Oxytocin.
3 parts of ant. pit.?
Pars distalis - bulk of gland.
Pars intermedia - forms separation form post. pit.
Pars tuberalis - wraps around infundibulum of post. pit.
2 parts of the post. pit.?
Pars nervosa - has neurosecretory axons and their endings.
Infundibulum - bridge of neurosecretory axons from hypothalamus to the pars nervosa.
Ways to tell ant. and post. pit apart on histolgy?
Ant. pit. is way more vascular.
Post. pit. is composed of axons and glia.
3 cell types in the pars distalis of the ant. pit.? What is the function of each?
Acidophiles - Somatotropes (GH) and Lactotropes (PRL)
Basophiles - Corticotropes (ACTH), Gonadotropes (FSH and LH), and Thyrotropes (TSH)
Chromaphobes - function unknown.
Which “-trope” cell is most prevalent in the pars distalis?
Somatotropes producing GH.
Are the axons of the post. pit. myelinated?
Nope.
Fine detail: Which nuclei make oxytocin and ADH?
Oxytocin - made in paraventricular nucleus.
ADH - made in supraoptic nucleus.
What are Herring bodies?
Hormones stored in granules in the terminals of axons of in the post. pit.
What are glia in the post. pit. called?
Pituicytes
Where does thyroid come from embryologically?
Endoderm lining of pharyngeal floor.
What’s in the follicles of the thyroid?
Thyroglobulin / aka. colloid - a precursor of thyroid hormone synthesis.
What are the 2 types of endocrine cells in the thyroid?
Follicular cells - make T3 and T4
Parafollicular cells (i.e. C cells) - make calcitonin
(each has an associated carcinoma)
Where to the parathyroid glands come from?
The 3rd and 4th pharyngial arches.
3 main cell types in the parathyroid?
Chief cells - make PTH
Oxyphil cells - function unknown
Adipocytes
3 layers of the adrenal cortex? What does each make?
GFR - salt, sugar, and sex
Zona Glomerulosa - mineralocorticoids (mostly aldosterone)
Zona Fasciculata - glucocorticoids
Zona Reticularis - androgens
(note that there is functional overlap between ZF and ZR)
Which of the 3 layers of the adrenal cortex is largest?
Zona Fasiculata - making glucocorticoids.
What do adrenal adenomas look like?
Giant yellow, steroid-filled, well-circumscribed things.
What cells are in the adrenal medulla?
Chromaffin cells, which are axon-less neurons- 2 types: some make NE, other make Epi
Reason why the adrenal medulla might be conveniently located?
Cortisol from ZF might inhibit growth of Chromaffin axons, and induce enzymes that convert NE to Epi.
What’s a pheochromocytoma?
Tumor of adrenal medulla producing catecholamines. Often presents with hypertension (more on this in the pathology lecture).
In what part of the pancreas are islets most numerous?
In the tail.
3 major cell types in the islets of Langerhans? (there are others… but..) Where are they generally located within the islet?
alpha cells - make glucagon - on periphery of islet.
beta cells - make insulin - the center of the islet.
delta cells - make somatostatin - scattered throughout islet.
About what percent of the pancreas volume to the islets compose?
Only 1-2%
