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What are the mechanisms involved in kidney's role in BP?
(p.20)
- Renin-angiotensin mechanism
- Sodium homeostasis
- Renal vasodepressor substances (dilators)
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What is kidney's role in regulating BP?
HUMORAL FACTORS
- Constrictors - increase BP
- = angiotensin II - most powerful vasoconstrictor
- = catecholamines
- = thromboxanes
- = leukotrienes
- = endothelin
- Dilators - decreased vascular resistance, decreased BP, relaxing factors
- = prostaglandins
- = kinins
- = nitric oxide / EDRF
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What is kidney's role in regulating BP?
VOLUME FACTORS
- sodium --> drink water --> retain volume
- mineralcorticoids - encourage sodium retention --> volume retention
- atrial natriuretic peptides - encourage volume retention
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What are determinants of arterial BP?
(p.19)
BP = CO x PR
- CO = cardiac output
- PR = peripheral resistance
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Blood Pressure is influenced by ...
- Blood volume
- Humoral factors
- Cardiac factors
- Neural factors
- Local factors
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What effect do humoral factors have on renal vasculature (e.g., PGE2)?
(p.20)
- PGE2 - prostaglandin E2 - Relaxing Factors
- = cause vasodilation
- = improves glomerular blood flow
- = decrease ischemia
- = counterbalance effects of vasoactive agents - renin, endothelin, angiotensin
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Essential Hypertension
(p.19)
- 90%
- Idiopathic
- Cause unknown
-
Secondary Hypertension
- 10%
- Causes:
- = renal disease
- = narrowing of renal artery from atheromatous plaque
- = adrenal disorders
- - aldosteronism
- - Cushing's
- - pheochromocytoma
-
What physiologic factors contribue to essential hypertension?
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Risk factors for hypertension
(p.21-22)
- genetics
- race - African-American
- age - 35-45 yrs
- sex - female > male; females better prognosis
- environmental - stress
- diet - obesity and salt
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Treatment and management of hypertension
- weight loss
- diet - decrease sodium (Na+), increase potassium (K+)
- exercise
- decrease alcohol
- stop smoking
- medication if needed
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What effect does cytosolic Ca2+ and Mg2+ have on arterial smooth muscle cells?
(p.23)
- Calcium = constriction
- Magnesium = dilation
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