Flashcards in 12.7 B Deck (22):
What are the criteria for hypertension?
diastolic above 90, systolic above 140
What is primary hypertension?
hypertension in which the underlying cause is unknown
What is secondary hypertension?
hypertension in which the underlying cause is known
What are three theories behind the cause of primary hypertension?
- abnormal functioning of the Na/K ATPase causing elevated cytosolic calcium levels
- decreased levels of NO
- increased levels of endothelin-1
How does age affect the reason for hypertension?
- younger people more affected by increased CO
- older people more affected by increased TPR
Older people often suffer from hypertension because of what increase compared to younger people?
an increase in TPR
Why as people age does TPR become increasingly responsible for essential hypertension?
- arterioles hypertrophy in response to high BP, reduce diameter and increasing contractile force
- decreased ventricular compliance due to ventricular hypertrophy impairs diastolic filling
Secondary hypertension is most often the result of what three underlying conditions?
- renal parenchymal disease
- renovascular disease
How does renal parenchymal disease lead to hypertension?
- nephron damage
- impaired renal excretion of sodium and water
- increased blood volume, preload, SV, and CO
How does renovascular hypertension lead to systemic hypertension?
- plaques in renal arteries impair blood flow
- renin secretion is increased
- angiotensin II formation increases
- ANG2 causes arteriolar and venous constriction as well as increased aldosterone secretion (which increases blood volume)
Renovascular hypertension is due to increases in (CO/TPR).
both, arteriolar constriction increases TPR while venous constriction and aldosterone increase CO
How does pheochromocytoma lead to hypertension?
- tumor in adrenal medulla secretes epi and NE
- triggers arteriolar constriction, venous constriction, increased inotropic state, and increased HR
How does primary hyperaldosteronism lead to hypertension?
- adrenal gland tumor causes increased plasma aldosterone
In addition to hypertension, hyperaldosteronism causes what?
potassium secretion and therefore skeletal muscle weakness
What is baroreceptor desensitivity?
the idea that the baroreflex gets desensitized to chronic increases in hypertension and doesn't respond as strongly to increased MAP
How can we tell the difference, clinically, between systolic dysfunction and diastolic dysfunction that both present as heart failure?
systolic dysfunction will present with a reduced ejection fraction while diastolic does not
How does hypertension increase the risk of MI?
by leading to ventricular hypertrophy and increasing the oxygen needs of the heart
How does hypertension cause arterial damage?
- hypertension leads to endothelial dysfunction, which then leads to thrombus formation and possibly stroke
- it may also physically rupture a vessel
What are the four best lifestyle changes to make that will reduce the risk of hypertension?
- decrease body weight
- reduce salt intake
- reduce alcohol consumption and tobacco use
Beta blockers do what to cardiac function?
decrease heart rate and inotropic state
How do ACE inhibitors and angiotensin reduce CO?
through venodilation which will reduce venous return and CO