Endocrine Flashcards
what type of cells make up endocrine glands?
epithelial cells
what are the three classes of hormones and how are these classified?
classified based on their chemical structure into peptides, steroids and amino acids
name examples of the three hormone classifications
amino acids e.g. thyroid hormones
steroids e.g. gonadal and adrenocortical steroids,
peptides e,g, insulin, ACTH, GH.
what is the consequence of lacking ducts in endo glands?
the secretions by parenchymal cells move into interstitial space where they reach their target cells via extracellular CT/ vascular system/
what types of hormones do cell surface and intracellular receptors interact with?
cell surface: peptide and catecholamine
intracellular: steroids and thyroid hormones
what are the two systems by which hypothalamus coordinates endocrine functions, and what does each involve?
hypothalamo-hypophyseal tract which involves paraventricular and supraoptic nuclei linked to posterior lobe of pituitary.
hypothalamo-hypophyseal portal system which carries neuroendocrine secretions of hypothalamus directly to the anterior lobe.
different names of anterior pituitary and posterior pituitary?
anterior: adenohypophysis, pars distalis
posterior: neurohypophysis and pars nervosa.
what is the origin of superior hypophyseal arteries and what do they supply?
they arise from internal carotid and PCA of Willis,
they supply infundibulum, pars tuberalis, median eminance.
origin of inferior hypophyseal arteries and their supply?
arise only from ICA, supply pars nervosa.
T/F: most of the anterior lobe doesn’t have a direct arterial supply.
true
where do primary and secondary capillary plexuses come from and
primary:arteries that supply infundibulum, median eminance and pars tuberalis
Secondary: hypophyseal portal veins
what is the path of hypothalamo-hypophyseal portal system?
secretions go from infun, M.eminance, and P.Tuberalis via primary capillary plexus which drains into hypophyseal portal veins which themselves give rise to secondary C.P which releases those secretions into pars distalis.
what are the divisions of adenohypo?
pars distalis (anterior lobe), pars intermedia and pars tuberalis.
what cells give rise to pars intermedia?
vestigial left over cells from Rathkespouch
what cells does pars distalis consist of?
cords of glandular epi cells within a rich network of large fenestrated cap.
what are three classes of cells in adeno?
basophils, acidophils and chromophobes.
what is the function of folliculostellate cells?
start shaped, connect p.Tuberalis to p.distalis via gap junctions to coordinate hormone release
what are the different cell types in acidophils and basiphils?
acido: somatotrophs and mammotrophs
baso: cortico, gonado and thyro
what does neurohypophysis produce?
oxytocin and antidiuretic hormone/ADH
what nuclei produce oxytocin and ADH?
supraoptic and paraventricular
what is the pathway of hormone secreted to go to neurphypophysis
oxy and ADH are secrete from paraventricular and supraoptic respectively which move down the nonmyelinated axons of hypo-hypo tract and get stored in accumulation if neurosecretory granules called herring bodies.
function of pars intermedia?
release melanocyte-stimulating hormone and endorphins
what cells constitute pars intermedia?
chromophobes and basophils which surround small spaces filled with eosinophilic colloid.
what do parafollicular cells secrete and the secretions’ role?
calcitonin, in concert with parathyroid hormone regulates blood calcium levels.
what is stored as colloid in thyroid gland?
inactive form of thyroid hormone called thyroglobulin-eosinophilic staining