Term
| What are the 2 cell types present in the pancreas, their relative abundance, and defining histological features |
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Definition
1. Exocrine and endocrine (islet of langerhans)
2. Exocrine cells are much more abundant then IOL cells
3. Exocrine cells stain dark pink (due to presence of hydrolytic enzymes) whereas IOL cells stain very light pink (almost white) |
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Term
| The vast majority of cells in an IOL produce what hormone? |
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Definition
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Term
| How does secretion vary in exocrine vs. IOL cells in the pancreas? |
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Definition
Exocrine cells secrete into the duodenum
IOL cells secrete into the bloodstream |
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Term
| What are the 4 cell types in an IOL and what does each secrete? |
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Definition
Alpha - glucagon
Beta - insulin
Delta - Somatostatin - negative feedback, inhibits further release
PP - Pancreatic polypeptide - coordinates hormone and digestive process |
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Term
| What factors regulate IOL hormone release? |
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Definition
1. Circulating nutrients
2. ANS innervation (stress response increases glucagon)
3. Gut hormones to regulate digestion
4. IOL hormones self regulate |
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Term
| Describe the biosynthesis of insulin |
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Definition
1. Preproinsulin is synthesized in response to high blood glucose levels (synthesized in the ER by recognition of a signal peptide)
2. Signal peptide is cleaved off
3. Disulfide bonds form between A and B chains and folding occurs
4. Peptide moves to trans Golgi
5. proteases cleave off the C peptide, making biologically active insulin
Note: To detect the recovery of patients with respect to insulin production, you want to measure C peptide levels in blood |
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Term
| What two embryologic layers give rise to the adrenal glands? |
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Definition
1. Endoderm gives rise to the cortex
2. Neural ectoderm gives rise to the medulla |
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Term
| What compounds are produced in the medulla of the adrenal gland? |
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Definition
| Catecholamines (this is the neural part of the adrenal gland) |
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Term
| What is produced in the cortex of the adrenal gland |
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Definition
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Term
| What are the 3 layers of the cortex? |
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Definition
1. Zona glomerulosa
2. Zona fasciculata
3. Zona reticularis |
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Term
| What aspect of cortex cells makes them stain light? |
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Definition
| Presence of lipid droplets (most prominent in ZF cells) that contain cholesterol for hormone precursors |
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Term
| What hormones are produced in the zona glomerulus? |
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Definition
| Mineralcorticoids (aldosterone) |
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Term
| What hormones are produced in the ZF? |
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Definition
| Glucocorticoids and gonadocorticoids |
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Term
| What hormones are produced in the ZR |
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Definition
| Mostly gonadocorticoids, but some glucocorticoids as well |
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Term
| Describe the differences in hormone release in the cortex vs. the medulla of the adrenal glands. |
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Definition
Cortex - release is stimulated by ACTH
Medulla - release is stimulated by neural signals |
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