Endocrine Glands Flashcards
Hormones
signaling molecules that are released into the bloodstream and regulate a variety of physiologic functions and metabolic processes
- act long-distance
- distributed by circulation
- released into bloodstream or interstitial fluid
Properties of endocrine glands (4)
- most consist of epithelial tissue (some are derived from neural crest or neurons)
- no ducts are present
- highly vascular
- hormones may be stored in intracellular secretory granules
Hormones are divided in to these two categories (and name examples)
Membrane impermeable (hydrophilic): peptides and proteins, glycoproteins, modified aa’s (receptors are on cell surface - act through secondary messengers)
Membrane permeable: steroid and thyroid hormones (receptors are intracellular DNA binding proteins that affect transcription)
Characteristics of cells producing protein hormones (4)
- abundant rough ER
- prominent golgi
- hormones often stored in secretory granules
Characteristics of cells producing steroid hormones (4)
- centrally located nucleus
- lipid droplets in cytoplasm
- abundant smooth ER (for cholesterol synth)
- spherical mitochondria with characteristic tubular or vesicular cristae
Hypophysis embryonic origin and fun facts about the anterior and posterior pituitary
AP (adenohypophysis) is derived from oral ectoderm and consists of epithelial tissue
PP (neurohypophysis) is derived from neural ectoderm.
AP has three regions: pars tubercles, pars distills, and pars intermedia.
PP contains no secretory cells - it stores hormones produced in hypothalamus
Cells of the anterior pituitary can be divided into two groups based on their staining in routine histological preparations
Chromophils and chromophobes
Chromophils
Cells containing secretory granules that interact with the dyes: basophils and acidophils
Chromophobes
Cells that do not contain brightly stained granules – includes stem/progenitor cells and cells that have released their granules or lost their granules during fixation
__________ is a type of chromophil that produces two types of protein hormones: __________ and __________
Acidophils; Growth hormone and Prolactin (GPA)
________ is a type of chromophil that produces glycoprotein hormones and small polypeptide hormones: name them
Basophils; FSH, LH, TSH; and polypeptide = ACTH and beta-LPH
B-FLAT
Somatotropic cell (stain affinity, % of cells, hormone produced and it’s physiologic activity)
Acidophilic; 50%; somatotropin (aka GH); growth of long bones and other growth-related processes
Lactotropic or mammotropic cell (stain affinity, % of cells, hormone produced and it’s physiologic activity)
Acidophilic; 15-20%; Prolactin; Stimulation of milk secretion
Gonadotropic cell (stain affinity, % of cells, hormone produced and it’s physiologic activity)
Basophilic; 10%; FSH, LH (often produced by the same cell); FSH: stimulation of gametogenesis; LH: regulation of estrogen and androgen secretion; promotes ovulation in females
Thyrotropic cell (stain affinity, % of cells, hormone produced and it’s physiologic activity)
Basophilic; 5%; Thyrotropin (TSH); stimulation of thyroid hormone secretion
Corticotropic cell (stain affinity, % of cells, hormone produced and it’s physiologic activity)
Basophilic; 15-20%; ACTH and B-lipotropin; ACTH: stimulation of adrenal cortical hormone secretion; B-lipoprotein: promotes utilization of fat
Each cell type in the AP secretes only one hormone type – name the two exceptions
Gonadotropic cells produce FSH and LH; Corticotropic cells produce ACTH and B-LPH
Pars Intermedia
Largely inactive in adults and contains colloid-filled follicles and cysts (Rathke’s cysts) of unknown function
Posterior pituitary contains two cell types: ______ and ______. Cell bodies of the neurons are located in the __________. The two hormones secreted are ____ and _____ and are stored in dilated eosinophilic axons called ______.
Neurons (their axons) and glial cells called pituicytes; hypothalamus; vasopressin (ADH) and oxytocin; Herring bodies
Functions of the posterior pituitary hormones
Vasopressin/ADH: regulation of blood osmolarity, increases water reabsorption in kidney collecting ducts
Oxytocin: stimulation of uterine contraction during childbirth and contraction of myoepithelial cells of mammary glands during nursing
Hypothalamus regulates the functions of the ________ via releasing and inhibiting hormones into the ____________.
Adenohypophysis; hypothalamo-hypophyseal portal system
Adrenal cortex is of _______ origin, has 3 concentric zones (name them), and has typical features of steroid producing cells (name 4)
Epithelial; zona glomerulosa, zona fasciculate, zona reticularis
- centrally located nucleus
- acidophilic cytoplasm with lipid droplets
- abundant smooth ER (for cholesterol synth)
- spherical mitochondria with tubular cristae (contain enzymes involved in synthesis of steroid hormones from cholesterol)
Adrenal medulla is of ____ origin, has electron-dense granules that react with ____ and _____ (and the cells are therefore called _____ or _____). It produces ________.
Neuronal; chromium and silver salts (chromaffin or argentaffin); catecholamines (epi and NE)
Zona glomerulosa (morphology, cell appearance/staining type, hormone produced, physiologic activity, regulated by)
Rounded cords of cells; steroid producing cells (appear foamy – most in fasciculata); mineralcorticoids (aldosterone); regulation of salt balance; angiotensin II