Endocrine

• Pituitary gland – two different sides, the less cellular side with lots of black dots is the pars nervosa or posterior pituitary. Remember that this side is neural ectoderm in origin and no hormones are produced here (that is not hard to figure out considering that these are just axons and nerve terminals). The pink circles are the Herring bodies which stores the hormones-oxytocin and vasopressin (ADH). The other half is the anterior pituitary or the pars distalis. Remember that this part is oral ectoderm in origin (Rathke’s pouch). There are three cell types here, the gray ones are the chromphobes which don’t do much so who cares, the pink ones are the eosinophils and they secrete prolactin and growth hormone. The blue-ish ones are the basophils. Remember, “B-FLAT” which is “B” for basophil, “F” for FSH, “L” for LH, “A” for ACTH, “T” for TSH. If you remember that, you will always get the hormones straight.

• Adrenal gland - make sure you know the three regions of the cortex and what is produced there. Remember “salty sweet sex” (no I didn’t make that up) Outside

• Zona Glomerulosa - ”salty”-mineralocorticoids (aldosterone), Zone Fasiculata-”sweet”-glucocorticoids/cortisol, Zona Reticularis-”sex” for androgens. The medulla has the chromaffin cells, neural crest in origin. They take the place of the post-ganglionic sympathetic neurons and therefore they secrete norepinepherine and epinephrine.

• Thyroid - unique looking organ, shouldn’t be confused with any other. Make sure you know the follicles with the colloid material that contains TGB (thyroglobulin). In between the follicles you will find cluster of cells the parafollicular or “C” cells. These are neural crest in origin and secrete calcitonin.

Category: Anatomy Notes