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27 Cards in this Set
- Front
- Back
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what is the difference btwn exocrine and endocrine glands?
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exocrine release their product into a system of ducts.
endocrine release their product into the blood stream that are destine for target organs. |
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why is the hypothalmus so important?
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it coordinates endocrine gland funtion and integrates endocrine and ANS functions
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what is the order of the hoemone release from the hypo to the ant. pit?
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axon terminals-primary capillary plexus (fenestrated cap's)-hypophyseal portal veins-secondary capillary plexus-parenchyma of ant pit.
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what are the releasing and inhibiting hormones of the hypothalmus?
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1. GHRH-which stimulates the secretion of somototropin (GH)
2. PRH-stim. secretion of prolactin 3. PIF 4. CRH-stim. secretion of ACTH 5. TSH-RH-stim secretion of TSH 6. GnRH- stim secretion of LH and FSH |
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what are the two cell types of chromophils?
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acidophils (most common), basophils
located in the pars distalis of the ant pit. |
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what are the acidphilic cells of the ant. pit?
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somatotropes (stim by GHRH and secrete GH)
lactotropes (stim by PRH, inhibited by PIF, secrete prolactin) |
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what are th basophilic cells of the ant. pit?
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corticotropes (stim by CRH, secrete ACTH and LPH)
thyrotropes (stim by TRH, secrete TSH, inhibited by T3/T4 in blood) gonadotropes (stim by GnRH, secrete FSH and LH) |
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what are the two cell types of the ant pit pars distalis?
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chromophils (acido and baso)
chromophobes (don't have an affinity for dye) |
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what is acromegaly?
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excessive GH in adults
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The ant pit is divided into three regions. What are they?
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Pars distalis, pars intermedia, pars tuberalis
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which is not an endocrine gland, ant pit or post pit?
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post pit
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what is the post pit?
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aka "pars nervosa"
serves as storage depot for neurosecretions produced by nerurons of the supraoptic and paraventricular nuclei, which are ADH and oxytocin |
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what are herring bodies?
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neurosecretory granules in the axon of the hypothalamohypophyseal tract
nervous stim causes these granules to release their contents (ADH or oxytocin) near capillaries |
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Where do pituitary adenomas occur? (Be specific)
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ant pit
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What hormones does the Thyroid gland synthesize?
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T3/T4- reguate cell and tissue metabolism and heat production
calcitonin- decreases blood calcium levels |
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Describe the histology of a thyroid follicle.
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lumen is surrounded by basal lamina, then reticular fibers, then fenestrated capillary plexus
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what are pituicytes?
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glia-like cells, cover and support axons and their terminals
found in the post pit |
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What is diabetes insipidus?
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may be caused by damage to the hypothalamus or the pars nervosa
results in reduction of ADH insufficient water resorption by kidney polyurea and dehydration |
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When thryoid follicles are functioning at normal levels of activity what type of epithelium do they display? squamous, cuboidal, columnar?
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simple cuboidal
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What is unique about the throid follicles when compared to most other endocrine glands?
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they store glandular secretory product in the follicular lumen (extracellularly) while other endocrine glands accumulate their product in the parenchyma (cellular part of the gland)`
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follicular cell vesicles of the thyroid gland contain what?
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thryroglobulin- important to synthesizing T3 and T4
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parafollicular cells are also known as what?
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clear cells, C cells
they also synthesize calcitonin (calcitonin is like an alarm, it becomes active only when there is a problem) |
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How are thyroid hormones synthesized (starting from the secretion of TRH to T3/T4)?
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TRH from hypothalmus-stim TSH secretion from ant pit-TSH binds to receptors on basal membrane of thyroid follicular cells-production of T3/T4
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Thyroglobulin is not a hormone, so what is it?
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storage form of the throid hormones
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What is needed in the actual production of T3/T4?
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Iodine iodinizes Thyroglobulin in the follicular lumen and is catalyzed by thyroid peroxidase, producing MIT and DIT.
several coupling rxn of MIT and DIT occur, giving you inactive forms of T3/T4 |
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How is T3 made?
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most of T3 is producd via conversion from T4 by the kidney, liver and heart.
T4 is produced only by he throid follicular cells. |
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Increase in thyroid hormone synthesis results in what?
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dec. in body weight, chol. syn., phospholipids and triglycerides
inc. heart rate, metabolsim, respiration, muscle function, appetite, etc |
