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58 Cards in this Set
- Front
- Back
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General features of endocrine organs:
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-Ductless
-Predominantly parenchyma; little stroma -Abundant blood supply; fenestrated capillaries -Each cell is adjacent to capillary or lymph vessel |
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protein and polypeptide hormones
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-Synthesized on rER
-Stored in granules -Released by exocytosis -Hydrophilic: No requirement for blood transporters -Bind to receptors on cell membrane -Activate second messenger systems |
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steroid and fatty acid derivative hormones
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-Synthesized on sER
-Diffuse through cell membrane -Hydrophobic: require blood carriers (e.g. albumin) -Bind to cytoplasmic or nuclear receptors -Act as transcription factors |
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Which class of hormones require blood transporters?
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steroid and FA derivs= hydrophobic
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Which class of hormones activate second messenger systems?
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protein and polypeptides
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Which class of hormones bind to cytoplasmic or nuclear receptors?
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steroid and FA derivs: easily pass through cell membranes because they are hydrophobic
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Which class of hormones act as transcription factors?
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steroid and FA derivs
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What 2 sub-classes of hormones are amino-acid derivatives?
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thyroid hormones (T3, T4) & catecholamines; both derivatives of tyrosine
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Which amino acid derivative hormones act like steroid hormones? Which act like protein hormones?
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-thyroid hormones: steroids
-catecholamines: proteins |
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The _____ is connected to the hypothalamus by the infundibulum.
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pituitary gland
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Where does the adenohypophysis come from?
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it is the anterior lobe and is an upward evagination of ectoderm from the roof of the mouth (Rathke's pouch)
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Where does the neurohypophysis come from?
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it is the posterior lobe and is a downgrowth of neurectoderm from the diencephalon
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Which lobe of the pituitary gland stains darker?
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anterior
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Hypophyseal portal system
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hypothalamus secretes hormones into incoming arterial blood which goes to primary capillary bed to portal vein to secondary capillary bed in anterior pituitary to stimulate release/inhibition of hormones which get dumped into outgoing veins from pituitary to the bloodstream.
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anterior pituitary: What hormones to basophils and acidohils release?
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-Acidophils: (pink) GH, Prolactin
--"GPa" Basophils: (purple) FSH, LH, ACTH, TSH --"b-FLAT" |
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Acidophils stain with _____ and secrete _____ hormones.
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eosin, peptide
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growth hormone is a _____ and is inhibited by somatostatin.
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somatotrope; Up-regulates metabolism and promotes long bone growth and muscle growth
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_____ is a mamotroph and is inhibited by dopamine.
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Prolactin; prevents ovulation and stimulates growth of mammaries... nice. Dopamine comes from the hypothalamus; basal level keeps prolactin in check.
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What are the 2 gonadotropes? What do they do?
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-FSH: stimulate development of ovarian follicles and production of ABP in Sertoli cells
-LH: stimulate steroidogenesis in ovarian follicles & corpus luteum and controls rate o testosterone synth by Leydig cells |
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What is the corticotropin? what's it do?
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ACTH: stimulate glucocorticoid synth in zona fasiculata & reticularis of adrenal glands
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thyrotropes
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TSH: stimulate production of thyroid hormones by the epithelial follicular cells
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GPa & b-FLAT
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anterior pituitary:
-acidophils: GH, Prolactin -basophils: FSH, LH, ACTH, TSH |
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Hypothalamic releasing hormones:
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-GHRH
-Somatostatin (GHIH) -Dopamine -GnRH -CRH -TRH |
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how does the hypothalamus tell the neurohypophysis what to do?
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-supraoptic and paraventricular nuclei in the hypothalamus send axons into the post pituitary through the hypophyseal tract... hormones get secreted into venous circulation
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T/F: pars nervosa has no secretory cells.
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true; just axons and glia
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Are posterior pituitary axons myelinated?
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nope
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pituicytes
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-pars nervosa support cells; astrocyte-like glial cells
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Herring bodies
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-pars nervosa granule filled dilations in axons which release ADH oxytocin
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ADH
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pars nervosa releases; stimulates H20 reabsorption in the renal medullary collecting ducts
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oxytocin
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pars nervosa releases; milk ejection and uterine contractions
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thyroid: parafollicular and follicular cells
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-parafollicular (C) cells: calcitonin- tells osteoclasts to stop
-follicular (epithelial) cells: (principal cells) T4 & T3 |
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What are thyroid colloids?
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iodinated (inactive) TH storage; surrounding the big fat colloids are parafollicular cells
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which is more active, T3 or T4?
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T3... T4 gets converted to T3 in the body
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TH is made of 2 _____ molecules with either 3 or 4 _____ attached.
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tyrosine, iodine
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Grave's disease: hypo or hyper?
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hypertyroid; TSH perpetually activated by circulating immunoglobulin
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calcitonin effects:
-released in response to: -lowers activity of: -inc or dec urine calcium: -inc or dec GI absorption of Ca: -End result: |
-high blood calcium
-osteoclasts -inc urinary calcium -dec GI absorption of Ca -*decrease blood calcium levels* |
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lack of iodine causes _____, among other things.
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-goiter: thyroid hypertrophy
-lack of dietary iodine hinders TH synth. |
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Thyroid cancer occurs more in women or men?
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women
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Hashimoto's disease
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-HYPOthyroidism
-autoimmune destruction of thyroid; invasion by lymphocytes and plasma cells, attacking follicular cells. |
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How many glands make up the thyroid gland?
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4, on the posterior trachea
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parathyroid gland 2 cell types:
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-principal cells (chief cells): PTH- regulates calcium and phosphate levels; tell osteoclasts to dig in; polygonal shaped
-oxyphil cells: round... fnx unknown |
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PTH overall role?
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raise blood calcium
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hypoparathyroidism
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blood calcium is increased and blood phosphate is low. Bone cysts may develop
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hyperparathyroidism
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bones are often denser & more mineralized. Low calcium levels may result in muscular tetany (uncontrollable fasciculations and contraction of the muscle).
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Suprarenal cortex arises from _____ whereas medulla arises from _____.
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mesoderm, neural crest; arterial supply separate, venous supply combined.
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Sympathetic ganglionic nerve cells may be visible in the _____.
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medulla
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the adrenal (suprarenal) gland cortex secretes _____ hormones and is ______ derived
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steroid, mesoderm
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The adrenal (suprarenal) gland medulla secretes ______ and is _____ derived
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catecholamines, neural crest
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chromaffin cells
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adrenal medulla: modified sympathetic postganglionic neurons
-secrete catecholamines -fight, flight, fright or exercise response |
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Aldosterone
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-Secretion is triggered by low blood pressure
-Increased uptake of sodium and water by the kidneys, which causes an increase in blood volume and blood pressure |
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Cortisol
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-Secretion is triggered by stress
-Stimulates gluconeogenesis (formation of new glucose from amino acids) |
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GFR-salt, sugar, sex. What about the medulla?
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-GFR: cortex
-medulla: catecholamines |
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What regulates circadian rhythms?
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pineal gland; works in harmony with the hypothalamus gland which directs the body's thirst, hunger, sexual desire and the biological clock that determines our aging process
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corpora arenacea
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brain sand: pineal gland
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melatonin
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-pineal gland: tryptophan → serotonin → melatonin; released immediately upon being synthesized
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endocrine pancreas: islets of Langerhans
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-Alpha cells, 20%: glucagon
-Beta cells, 60%: insulin -Delta cells, 5%: somatostatin "A-B-D_GIS" |
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Somatostatin is released by the hypothalamus to inhibit GH release from the anterior pituitary... what does it do in the pancreas?
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inhibits release of glucagon and insulin from alpha and beta cells
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enteroendocrine cells
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-base of crypts of Leiberkuhn or in stomach pits of GI
-produce digestive hormones; each enteroendocrine cell secretes one type of hormone |
