Endocrine System Flashcards
What do somatotrophs secrete?
Growth Hormone GH
What is percentage of somatotrophs in anterior pituitary?
50%
Describe somatotroph LM structure
Many granules, acidophilic
What does growth hormone target?
All tissues
What do lactotrophs/mammotrophs secrete?
Prolactin
What does lactotrophs target?
Mammary glands for milk production
What is percentage of lactotrophs in anterior pituitary?
20%
Describe lactotroph LM structure?
Few granules, acidophilic, secretory vesicles are large and ovoid
What does Corticotrophs secrete?
ACTH and lipoprotein
What does corticotrophs target?
Adrenal cortex
What is percentage of corticotrophs in anterior pituitary?
10%
Describe corticotrophs LM structure
ACTH granules are large and polygonal and arranged in clusters, basophilic
What do Gonadotrophs secrete?
FSH and LH
What is percentage of gonadotrophs in anterior pituitary?
20%
What do gonadotrophs target?
Gonads
Describe gonadotrophs LM structure
Abundant small secretion granules and distended rER, basophilic
What do thyrotrophs secrete?
TSH
What is percentage of thyrotrophs in anterior pituitary?
5%
What does thyrotrophs target?
Thyroid gland
Describe thyrotroph LM structure
Characteristic tapering of ends of cell, small round secretory granules, basophilic
What does supraoptic nucleus synthesize?
Vasopressin/ADH
What does vasopressin do?
Increases permeability of distal portions of nephron and causes rapid water reabsorption in collecting ducts
What does paraventricular nucleus synthesize?
Oxytocin
What does oxytocin do?
Induces contractions of myometrium of uterus, induces contractions of myoepithelial cells of mammary gland for milk ejection
Where are supraoptic and paraventricular nucleus located?
Hypothalamus, deliver hormones to posterior pituitary
What are 4 releasing hormones of anterior pituitary?
Thyroid releasing hormone TRH, gonadotropin releasing hormone GnRH, growth hormone releasing hormone GHRH, corticotropin releasing hormone CRH
What are two inhibitory hormones of anterior pituitary?
Somatostatin and dopamine
What does thyroid releasing hormone do?
Stimulates release of TSH
What does thyroid releasing hormone do?
Stimulates release of thyrotropin
What does gonadotropin releasing hormone do?
Stimulates release of FSH and LH
What does growth hormone releasing hormone do?
Stimulates release of GH
What does corticotropin releasing hormone do?
Stimulates synthesis of POMC, and release of B-lipotropic hormone B-LPH and corticotropin ACTH
What does somatostatin inhibit?
Release of somatostatin GH, and TSH
What does dopamine inhibit?
Release of prolactin
What are the two acidophilic chromophils of anterior pituitary?
Somatotrophs, Lactotrophs/Mammotrophs
What are the three basophilic chromophils of anterior pituitary?
Corticotrophs, Thyrotrophs, Gonadotrophs
What are chromophobes?
Cells that do not pick up stain, no secretory granules, stem cells and degranulated cells
Where does anterior pituitary develop from?
Ectoderm roof of mouth, called Rathkes pouch
Where does posterior pituitary develop from?
Hypothalamus part of the dicephalon
What does anterior pituitary (pars distalis) consist of structure wise?
Clumps and cords of endocrine cells, fenestrated capillaries, supporting reticular fibers
What is main controlling center of the autonomic nervous system?
Hypothalamus
What are the 5 major endocrine glands?
Pituitary, Pineal, parathyroid, thyroid, adrenal glands
What are the 3 chemical classifications of hormones?
Polypeptides/Peptides/Proteins
Steroids
Amino Acids and Catecholamines
What organs produce polypeptides and hormones?
Hypothalamus, pituitary, thyroid, parathyroid, pancreas
What organs produce cholesterol derived steroids?
Ovaries, testes, adrenal cortex
What organs produce amino acids?
Thyroid gland,
Catecholamines are produced by adrenal medulla
What is autocrine signaling?
Signals binds to same cell producing signal
What is juxtacrine signaling?
Signaling to neighboring cells through GAP junctions
What is paracrine signaling?
Signaling through diffusion into extracellular fluid to nearby cells
What is endocrine signaling?
Signaling through the blood circulatory system
What tissue is pituitary composed of?
Glandular epithelial tissue and neural tissue
What is Pars distalis?
Anterior lobe of pituitary, 75%
What is Pars intermedia?
Narrow band of tissue that lies between pars distalis and posterior pituitary
What is pars tuberalis?
Band of tissue around infundibulum stem
What does pars intermedia produce?
Endorphins, MSH Melanocyte Stimulating Hormone
Chromophobes
Small colloid filled cysts
Where are small colloid filled cysts in pars intermedia derived from?
Lumen of embryonic Rathkes pouch
What do corticotropes produce here and cleave differently to produce MSH and endorphins?
POMC
What are most cells in pars tuberalis?
Gonadotrophs
What rhythm is Pineal gland on?
Circadian rhythm
What kind of capsule covers pineal gland?
Vascularized connective tissue capsule of pia matter
What does the vascularized connective tissue covering do to lobes as it extends into gland?
Divides gland into variously sized lobules
What does LM show of pineal gland?
Two types of cells, and BRAIN SAND
What is Brain Sand?
Concentrations of calcium and magnesium salts