Term
| What are the 3 congenital adrenal hyperplasias? What is the main difference between them? |
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Definition
11β-hydroxylase deficiency
17α-hydroxylase deficiency
21-hydroxylase deficiency
21 is the only one with hypotension (others are hyper)
17 is the only one with low androgens |
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Term
11β-hydroxylase deficiency:
- mineralocorticoid level
- cortisol level
- sex hormone level |
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Definition
high mineralocorticoid (but no aldosterone, uses 11-deoxycorticosterone instead)
low cortisol
high sex hormones |
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Term
17α-hydroxylase deficiency:
- mineralocorticoid level
- cortisol level
- sex hormone level |
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Definition
high mineralocorticoids (hypertension)
low cortisol
low sex hormones |
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Term
21-hydroxylase deficiency:
- mineralocorticoid level
- cortisol level
- sex hormone level |
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Definition
low mineralocorticoids
low cortisol
high sex hormones |
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Term
| What is the main difference between 11β-hydroxylase deficiency and 21-hydroxylase deficiency? |
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Definition
21-hydroxylase is one step before 11β-hydroxylase, and deficiency blocks 11-deoxycorticosterone formation (get hypotension)
11 is used one step after 21, so after 11-deoxycorticosterone is formed (get hypertension) |
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Term
| What affect does cortisol have on blood pressure and how? |
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Definition
| Increases blood pressure by upregulating α1 receptors on arterioles |
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Term
| Where is parathyroid hormone made? |
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Definition
| Chief cells of the parathyroid |
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Term
| Give the 4 general functions of PTH |
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Definition
Increases bone resorption of calcium and phosphate
Increases kidney resorption of calcium
Decreases kidney resorption of phosphate
Activates vitamin D through the kidney
(increases serum calcium and decreases serum phosphate) |
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Term
| Where in the kidney is calcium reabsorbed in response to PTH? |
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Definition
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Term
| How does PTH increase calcitrol? |
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Definition
calcitrol= active vitamin D= 1,25-(OH)2 vitamin D
It stimulates kidney 1α-hydroxylase which converts inactive vit. D (25-OH) to active (1,25-(OH)2) |
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Term
| What 2 things can increase PTH secretion? |
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Definition
Low free serum Ca2+
Low free serum Mg2+ (unless it's really low, since it's a cofactor for PTH) |
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Term
| How does PTH cause bone resorption? |
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Definition
| Increased production of M-CSF (macrophage colony stimulating factor) and RANK-L (receptor activator of nuclear factor-κ B ligand) in osteoblasts stimulates osteoclasts |
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Term
| What is the process of Vitamin D production? (3 steps) |
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Definition
D3 from sun exposure
Converted to 25-OH D in liver
Converted to 1,25-(OH)2 D in kidney |
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Term
| What is the biggest function of active vitamin D? |
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Definition
Increases instestinal absorption of calcium and phosphate
(also increases bone resorption of calcium and phosphate) |
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Term
| What 3 things stimulate active vit. D production? |
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Definition
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Term
| What vitamin D deficiency causes in kids vs adults. |
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Definition
kids= rickets
adults= osteomalacia |
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Term
| What is Calcitonin and where does it come from? |
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Definition
Decreases bone resoption of calcium in response to increased serum calcium.
From Parafollicular cells (C cells) of the thyroid. |
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Term
| How does SHBG (sex hormone binding globulin) affect testosterone? |
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Definition
More SHBG, less free testosterone (gynecomastia in men)
Less SHBG, more free testosterone (hirsutism in women) |
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Term
| 5 functions of thyroid hormone |
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Definition
1. Bone growth
2. CNS maturation
3. Increase β1 receptors in heart
4. Increase basal metabolic rate via ↑Na+/K+ ATPase activity
5. Increase glycolysis, gluconeogenesis, lipolysis |
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Term
| What is the feedback mechanism for thyroid hormone? |
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Definition
| Free T3 negatively feeds back to the ant. pituitary by decreasing its sensitivity to TRH |
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Term
Give 2 effects thyroid hormone has on growth
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Definition
Bonde growth
CNS maturation |
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Term
| What affect does thyroid hormone have on cardiovascular functions? |
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Definition
| Increases β1 receptors in heart |
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Term
| Give 3 effects thyroid hormone has on metabolic pathways |
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Definition
| Increase glycolysis, gluconeogenesis, lipolysis |
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Term
| How does thyroid hormone increase the basal metabolic rate? |
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Definition
| It increases Na+/K+ ATPase activity |
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