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Flashcards

Endocrine Glands

Brianne Schmiegelow Histology - DDS DDS English 46 cards

Cards in this deck (46)

  1. 1What are the general characteristics of endocrine glands?Composed of secretory cells of epithelial origin with prominent nuclei and numerous organelles
    Lack ducts
    Secrete hormones into surrounding interstitial space
    Possess rich blood supply with fenestrated capillary networks
    Communicate via chemical messengers (hormones)
  2. 2What coordinates endocrine functions?Hypothalamus
    Acts as intermediary between autonomic nervous system and endocrine system
  3. 3Where do you find endocrine and exocrine tissue intermixed?Pancreas
    Most other endocrine tissue form discreet organs
  4. 4What is another name for the pituitary gland?Hypophysis
  5. 5What is sella turcica?Part of sphenoid bone where the pituitary gland lies
    Beneath the third ventricle
  6. 6What is the hypophyseal portal system?Network of vessels which allows communication with the hypothalamus
  7. 7What are the types of pituitary hormones?Direct acting hormones
    - Have non-endocrine target organ
    - E.g. GH, ADH, MSH, oxytocin, prolactin
    Trophic hormones
    - Target organ is another endocrine gland
    - E.g. TSH, ACTH, FSH, LH
  8. 8What are the pituitary-dependent endocrine glands?Thyroid gland, adrenal cortex, and gonads
  9. 9What is found in the two portions of the pituitary?Anterior: glandular epithelial tissue
    Posterior: neural secretory tissue
  10. 10What is Rathke's pouch?Evagination of ectoderm from the oral cavity in the region of the pharynx
    What the anterior pituitary arises from
  11. 11What are the three other names for the anterior pituitary?Adenohypophysis
    Pars anterior
    Pars distalis
  12. 12What are the three regions of the anterior pituitary?Pars distalis: bulk of AP; secretes most pituitary hormones
    Pars intermedia: thin layer between anterior and posterior pituitary; secretes MSH and ACTH; frequently contains cystic remnants of Rathke's pouch
    Pars tuberalis: extension of AP; forms collar/pituitary stalk (AKA infundibulum)
  13. 13What hormones are secreted by the pars distalis of the anterior pituitary?Direct-acting: GH & prolactin
    Trophic: TSH, ACTH, FSH, LH
  14. 14How does the hypothalamus control secretions of the anterior pituitary?Via hypothalamic regulating factors (hormones)
    Releasing factors: stimulate secretion
    Inhibitory factors: inhibit secretion
  15. 15What are chromophils?Secretory cells of anterior pituitary that stain
    Acidophils stain with acidic dye (turn pink)
    - Somatotrophs: secrete GH
    - Mammotrophs (lactotrophs): secrete prolactin
    Basophils stain with basic dye (turn purple)
    - Thyrotrophs: secrete TSH
    - Gonadotrophs: secrete FSH & LH
    - Corticotrophs: secrete ACTH, MSH, endorphins
  16. 16What are chromophobes?Secretory cells of the anterior pituitary that don't stain
    Represent inactive cells
  17. 17What are the other names for the posterior pituitary?Neurohypophysis
    Pars nervosa
  18. 18What are the characteristics of the posterior pituitary?Has infundibulum with axons of neurosecretory origin
    Consists of downgrowth of nervous tissue from the floor of diencephalon (3rd vent)
    Composed of pituicytes (support cells) and neurosecretory nerve axons which store and release products from nerve cell bodies in the hypothalamus
    Secretion of PP hormones by axons known as neurosecretion and is regulated by hypothalamic hypophyseal feedback loop
  19. 19What hormones are secreted by the hypothalamus via the posterior pituitary? What do they do?ADH (aka vasopressin): controls blood pressure by altering the permeability of renal collecting tubules; synthesized by neuron cell bodies in the supraoptic nucleus of hypothalamus
    Oxytocin: promotes smooth muscle contraction in uterus and breast; synthesized by neuron cell bodies in paraventricular nucelus of hypothalamus
  20. 20What are Herring bodies?Dilations of axons of the posterior pituitary where ADH and oxytocin are stored in neurosecretory granules
  21. 21What are the characteristics of the hyroid gland?Bilateral, lobulated endocrine gland on anterior neck
    Has left and right sides connected by a narrow isthmus
    Surrounded by loose CT capsule with fine CT septa
    Embryologically derived from epithelial downgrowth of fetal tongue
    Stores large amounts of inactive thyroglobulin hormone in extracellular follicles lined by simple cuboidal epithelium
  22. 22How does the thyroid make thyroglobulin?Follicular epithelial cells concentrate iodine to 30-40X blood levels and then secrete it as thyroglobulin via apical microvilli
  23. 23What are the two active hormones produced by the thyroid? What happens to them after? What do they do?T3 (triiodothyronine) and T4 (tetraiodothyronine or THYROXINE)
    In the liver, T4 is deiodinated to make T3 which is the more potent, active form
    Regulates basal metabolic rate as well as growth/development of nervous system
  24. 24What happens with a thyroid hormone deficiency during fetal development?Impairs neural development and myelination
    Results in physical stunting and mental retardation (cretinism)
  25. 25What are parafollicular cells?AKA C cells AKA clear cells
    Secondary secretory cells in the thyroid gland that are located at the periphery of follicles or scattered within the CT
    In lower vertebrates, make up a separate organ
    Secrete calcitonin which works with PTH to regulate blood Ca levels
  26. 26What controls the synthesis, storage, and release of thyroid hormones?TSH from the anterior pituitary
  27. 27What is goiter?Enlargement of the thyroid gland
    Can be indicative of:
    Hyperthyroidism: increase in # and size of follicle cells
    Hypothyroidism: autoimmune reaction that results in decrease
    Dietary iodine deficiency: decreased TH production can lead to hypertrophy with non-functional thyroglobulin
  28. 28What are the characteristics of the parathyroid gland?Small, oval endocrine glands associated with thyroid
    Usually a superior and an inferior pair on posterior surface of thyroid gland
    Embryologically derived from third and fourth branchial (pharyngeal) pouches
  29. 29What is the function of the parathyroid gland?Secretes parathyroid hormone that regulates serum Ca and P (antagonistic to calcitonin)
    PTH slowly increases serum Ca, calcitonin rapidly decreases serum Ca
  30. 30How does PTH increase serum Ca?Increases osteoclast activity (inhibits osteoblasts)
    Increases renal tubular absorption of Ca in the kidneys and inhibits resorption of phosphate
    Increases Ca absorption from the gut via vitamin D
  31. 31What are Chief (principal) cells?Most abundant secretory cells in the parathyroid gland
    Secrete PTH
    Stain clear to light pink with dark nuclei and moderate amount of cytoplasm
  32. 32What are oxyphil cells?Larger, less numerous secretory cells in the parathyroid gland
    Stain dark pink with more cytoplasm
    Occur in clusters and contain large #s of mitochondria
    Function unknown
  33. 33What are the 3 functional classes of adrenal hormones? What do they do/Mineralocorticoids: e.g. aldosterone; control electrolyte and fluid balance (regulate Na and K levels via Na pumps and regulate blood pressure via JGA)
    Glucocorticoids: e.g. cortisol; stimulate gluconeogenesis and glycogenolysis (both increase blood glucose); increase metabolism of proteins/carbs/lipids
    Sex hormones: e.g. androgens; very small amount; supplement gonadal production
  34. 34What are the three layers of the adrenal cortex? What do they secrete?SUPERFICIAL TO DEEP
    Zona glomerulosa: ~15% of cortex; thin, dark-staining band; secretes mineralocorticoids
    Zona fasciculata: ~80% of cortex; broad, light-staining band; contains cells called spongiocytes; secrete glucocorticoids and small amounts of androgens
    Zona reticularis: ~5% of cortex; thin, dark-staining band; secretes small quantities of androgens and glucocorticoids
  35. 35What is hypoadrenocorticism?AKA Addison's disease
    Failure of adrenal cortex to produce hormones (usually due to atrophy of gland by autoimmune disease
    Decreased aldosterone leads to decreased ECF volume, hypoatremia, hyperkalemia, mild acidosis, shock, and death (aka Addisonian crisis)
    Decreased cortisol leads to decreased blood glucose
    Treated with mineral corticoids and glucocorticoids
  36. 36What is hyperadrenocorticism?AKA Cushing's disease
    Primary (adrenal): due to general adrenal hyperplasia or functional tumor of adrenal cortex that leads to excess cortisol secretion
    Secondary (pituitary): due to increased ACTH from the anterior pituitary or other cortisol-producing tumor leading to adrenal hyperplasia and excess cortisol secretion
  37. 37Where does the adrenal medulla originate from?Neuroectoderm
  38. 38What are chromaffin cells?Modified, post-ganglionic neuronal cells in the adrenal medulla that have secretory function
    Epithelioid in appearance
    Controlled directly by preganglionic, sympathetic nerve fibers
    Secrete catecholamines (adrenaline/noradrenaline) which are stored in dense core granules and have systemic effect on adrenergic receptors in the body to prepare body for "fight or flight" response
  39. 39What are enkephalins?Endogenous opiates responsible for pain relief
    Production promoted by adrenaline from the adrenal medulla
  40. 40What is a pheochromocytoma?Generally benign, functional tumor of chromaffin cells of the adrenal medulla
    Leads to increased epinephrine and norepinephrine secretion which causes hypertension, headache, cardiac arrhythmias, chest pain, anxiety, panic attacks, and nausea
    Treated with surgical removal of the tumor
  41. 41What are islets of Langerhans?Areas of endocrine tissue in the pancreas that aggregates around capillaries
    Have alpha, beta, and gamma cells
  42. 42What are the functions of the cell types in the islets of Langerhans in the pancreas?Alpha: 15-20% of cells; secrete glucagon; increases blood glucose, stimulates glucogenesis and glycogenolysis
    Beta: 70% of cells; secrete insulin; decreases blood glucose and stimulates intracellular glycogen synthesis
    Gamma: 5-10% of cells; secrete somatostatin; inhibits both insulin and glucagon produciton
    Other miscellaneous cell types secrete vasoactive intestinal peptide (VIP) and pancreatic polypeptide (PP)
  43. 43What is the pineal gland?6-8 mm long gland located anterodorsal to the cerebellum
    Develops from neuroectoderm as evagination of the posterior portion of the third ventricle, from roof of diencephalon
    Communicates with hypothalamus and acts as a photoreceptor in lower vertebrates
    Important in circadian rhythms and seasonal reproductive cycles
    Secretes melatonin (stimulates melano/chromato-phores) and serotonin (vasoconstrictor/neurotransmitter)
    In mammals has anti-gonadal effect (melatonin decreases GNRH from hypothalamus which decreases sex hormone secretion from gonads)
  44. 44What are the two main cell types in the pineal gland? What do they do?Pinealocytes (aka pineal chief cells): most common cell; highly modified neurons that secrete melatonin and serotonin
    Neuroglial cells (aka interstitial cells): support cells similar to astrocytes
  45. 45What is corpora arenacea?Calcified accretions of Ca and Mg phosphate that can be seen in the pineal glands of aging individuals
  46. 46—

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DDS Histology - DDS (Exam 3) Flashcards on Endocrine Glands, created by Brianne Schmiegelow on 30/11/2017.
Created by
Brianne Schmiegelow · Nov 2017
Updated
Feb 4, 2018
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