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50 Cards in this Set
- Front
- Back
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What is the function of the pineal gland? |
1. Directly sensitive to light 2. Coordinates daily and seasonal cycles with the environment light-dark cycle |
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How does the pineal gland develop? |
1. Outgrowth of diencephalon |
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What forms the capsule of the pineal gland? |
1. Pia mater |
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What are the corpora arenacea? |
1. Aggregates of calcium phosphate within the pineal gland |
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What are the types of cells found in the pineal gland? |
1. Pinealocytes 2. Glial cells |
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What is the structure of pinealocytes? |
1. Modified neurons 2. Large, euchromatic nuclei |
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What is the function of pinealocytes? |
1. Secrete melatonin |
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What does the secretion of the pinealocytes at its peak? |
1. Middle of the night |
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What controls the secretion/synthesis of melatonin? |
1. Norepinephrine |
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What is the structure of glial cells? |
1. Smaller, heterochromatic nuclei |
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What are the divisions of the parenchyma of the adrenal gland? |
1. Cortex 2. Medulla |
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What is the embryological origin of the adrenal cortex? |
1. Mesoderm |
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What is the embryological origin of the adrenal medulla? |
1. Neural crest--- ectoderm |
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What are the trabeculae of the adrenal gland? |
1. Thin offshoots of the capsule diving into the parenchyma of the gland |
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What happens to the steroid hormones in the adrenal gland post-production? |
1. They are released immediately |
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What are the divisions of the adrenal cortex? |
1. Zona glomerulosa 2. Zona fasciculata 3. Zona reticularis |
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What types of capillaries are found in the zona glomoerulosa? |
1. Fenestrated sinusoid |
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What do cells of the zona glomerulosa secrete? |
1. Mineralocorticoids |
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What is the principal mineral corticoid secreted by the zona glomerulosa? |
1. Aldosterone |
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What are spongiocytes? |
1. Large secretory cells in the zona fasciculata |
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What do spongiocytes secrete? |
1. Glucocorticoids--- cortisol 2. Androgens |
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What is the function of glucocorticoids? |
1. Increasing metabolism of glucose and fatty acids 2. Depress the immune and inflammatory responses |
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What interleukins are suppressed by glucocorticoids? |
1. IL-1 2. IL-2 |
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What stimulates secretion of glucocorticoids by spongiocytes? |
1. ACTH production by corticotropes of the adenohypophysis |
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What is the structure of the cells in the zona reticularis? |
1. Contain lipufuscin granules 2. Few lipid droplets 3. Stain intensely with eosin |
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What do the zones of the zona reticularis secrete? |
1. Androgens--- more pronounced than the zona fasciculata 2. Glucocorticoids--- regulated by ACTH |
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What is the principal secreting cells of the adrenal medulla? |
1. Chromaffin cells |
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How do chromaffin cells secrete hormones? |
1. Accumulate and store hormones in secretory granules |
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What are the principal hormones secreted by chromatin cells? |
1. Epinephrine 2. Norepinephrine |
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What causes chromaffin cells to secrete hormones? |
1. Innervated by sympathetic nerve fibers 2. Release of Ach causes degranulation of chromaffin cells |
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What is the function of ganglion cells in the adrenal medulla? |
1. Modulate the activity of chromaffin cells 2. Innervate blood vessels within the medulla |
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What is the function of capsular arteries? |
1. Irrigate the capsule |
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What is the function of cortical arteries? |
1. Branch within the cortex 2. Form a dense network of fnestrated cortical sinusoidal capillaries 3. Drain into medullary collecting veins |
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What is the function of the medullary arteries? |
1. Pass through the cortex 2. Form a dense network of fenestrated medullary sinusoidal capillaries |
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What is the blood supply to the medulla? |
1. Medullary arteries-- O2 2. Cortical capillaries-- glucocorticoid-rich blood |
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What is the function of adrenomedullary collecting veins? |
1. Receive blood from smaller blood vessels with the medulla 2. Drain into central adrenomedullary vein |
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What is the role of the central adrenomedullary vein? |
1. Drain into IVC on right side 2. Left renal vein on left side |
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What type of epithelium makes up the thyroid follicle? |
1. Simple cuboidal follicular epithelium |
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What is the substance at the center of a thyroid follicle? |
1. Colloid |
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What are the principal cells of the thyroid gland? |
1. Follicular cells |
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What is the structure of follicular cells? |
1. Squamous to low columnar 2. More active=taller epithelium |
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What hormones are synthesized by follicular cells? |
1. Thryoxine (T4) 2. Triiodothyronine (T3) |
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What is the function of thyroid hormones? |
1. Regulate metabolism 2. Regulate heat production 3. Influence body growth and development |
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What causes T3 and T4 to be released? |
1. TSH release by the pituitary |
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How are thyroid hormones produced? |
1. Thryoglobulin synthesized in RER and Golgi 2. Follicular cells transport iodide from blood into cytoplasm, iodide oxidized to iodine 3. Iodination of thyroglobulin results in either T3 or T4 |
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What is the reaction of follicular cells to TSH? |
1. Resorb colloid 2. Thyroglobulin is broken down by lysosomes 3. T3 and T4 are released |
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What is the function of parafollicular cells? |
1. Synthesis of calcitonin |
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What is the most numerous cell in the parathyroid gland? |
1. Parathyroid chief cell |
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What is the function of parathyroid chief cells? |
1. Production of PTH |
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What is the function of oxyphil cells in the parathyroid gland? |
1. Unknown 2. Have a large number of mitochondria in the cytoplasm |
