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Flashcards in Histology - Pituitary Deck (20):

Steroid hormones are derived from? Examples?


(e.g. estradiol, testosterone, cortisol, aldosterone)


Peptide and protein hormones are synthesized from? Examples?

amino acids

(e.g. prolactin, growth hormone, insulin, vasopressin)


Glycoproteins are peptides modified by addition of? Examples?

carbohydrate groups

(e.g. luteinizing hormone, follicle stimulating hormone, thyroid stimulating hormone)


Amine hormones are modified derivatives of? Examples?

the amino acid tyrosine

(e.g. thyroid hormone, norepinephrine, epinephrine) or tryptophan (e.g. melatonin)


Pituitary Gland (Hypohysis)

What are the two parts?

  • adenohypohysis (anterior lobe) 
  • neurohypohysis (posterior lobe)


The adenohypophysis is connected to the hypothalamus by

blood vessels – hypophysial portal circulation


The neurohypophysis is anatomically connected to hypothalamus by

  • the infundibulum 
  • the infundibular stem


Pituitary Gland

Pars distalis - cell types?

1. Chromophil Cells

A. Acidophils – most numerous cell type, red-staining cytoplasmic granules

B. Basophils – less numerous, blue-staining cytoplasmic granules


2) Chromophobe cells 

These cells exhibit only faint/weak staining, and probably represent committed stem cells and immature forms of acidophils and basophils, as well as degranulated acidophils/basophils


Somatotrophic cells (Pituitary)–

synthesize/secrete growth hormone (hGH), the most important hormone for normal growth; also has important effects on protein, carbohydrate, and fat metabolism


Mammotrophic cells (Pituitary)–

synthesize/secrete prolactin (PRL), the major hormone responsible for milk production; also important in normal development of breast glandular tissue.


Thyrotrophic cells (Pituitary)–

synthesize/secrete thyroid stimulating hormone (TSH), which stimulates growth and activity of thyroid hormone- secreting cells of the thyroid gland


Corticotrophic cells (Pituitary) –

synthesize/secrete adrenocorticotrophic hormone (ACTH), which stimulates growth and activity of steroid hormone-secreting cells of the adrenal cortex


Gonadotrophic cells (Pituitary) –

synthesize/secrete luteinizing hormone (LH) and follicle stimulating hormone (FSH), which regulate growth and activity of ovaries and testes, including secretion of the sex steroids, estrogen and testosterone


What are the two postierior pituitary hormones? Describe synthesis.

  • vasopressin (ADH) 
  • oxytocin


  1. synthesized in the cell bodies,
  2. packaged in secretory vesicles,
  3. transported down the axons and accumulated in the axon terminals 
  4. distended terminals are represented by Herring bodies in light microscopy


Pituitary adenomas –

typically very small, cytologically benign tumors of hormone secreting cells


Growth hormone-secreting adenomas cause

gigantism if present before closure of the growth plates or acromegaly when they develop after long bone growth has ceased.


ACTH-secreting adenomas result in

continuous stimulation of the adrenal cortex causing Cushing’s Disease


Prolactin-secreting adenomas (the most common pituitary adenoma) result in

galactorrhea (milk oozing from nipples) and hypogonadism/infertility in both males and females


Isolated hGH deficiency in children results in

decreased rate of linear growth, short stature, mild obesity, and (in many cases) delayed puberty.


Central (neurogenic) diabetes insipidus –

in the absence (or severe deficiency) of ADH, the collecting ducts cannot reabsorb water, so excess water is excreted in urine (as much as 10-12 liters per day).